| /* |
| * Copyright (C) 2011 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package android.support.v4.view; |
| |
| import android.content.Context; |
| import android.content.res.TypedArray; |
| import android.database.DataSetObserver; |
| import android.graphics.Canvas; |
| import android.graphics.Rect; |
| import android.graphics.drawable.Drawable; |
| import android.os.Parcel; |
| import android.os.Parcelable; |
| import android.os.SystemClock; |
| import android.support.v4.os.ParcelableCompat; |
| import android.support.v4.os.ParcelableCompatCreatorCallbacks; |
| import android.support.v4.widget.EdgeEffectCompat; |
| import android.util.AttributeSet; |
| import android.util.Log; |
| import android.view.FocusFinder; |
| import android.view.Gravity; |
| import android.view.KeyEvent; |
| import android.view.MotionEvent; |
| import android.view.SoundEffectConstants; |
| import android.view.VelocityTracker; |
| import android.view.View; |
| import android.view.ViewConfiguration; |
| import android.view.ViewGroup; |
| import android.view.ViewParent; |
| import android.view.accessibility.AccessibilityEvent; |
| import android.view.animation.Interpolator; |
| import android.widget.Scroller; |
| |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.Comparator; |
| |
| /** |
| * Layout manager that allows the user to flip left and right |
| * through pages of data. You supply an implementation of a |
| * {@link PagerAdapter} to generate the pages that the view shows. |
| * |
| * <p>Note this class is currently under early design and |
| * development. The API will likely change in later updates of |
| * the compatibility library, requiring changes to the source code |
| * of apps when they are compiled against the newer version.</p> |
| */ |
| public class ViewPager extends ViewGroup { |
| private static final String TAG = "ViewPager"; |
| private static final boolean DEBUG = false; |
| |
| private static final boolean USE_CACHE = false; |
| |
| private static final int DEFAULT_OFFSCREEN_PAGES = 1; |
| private static final int MAX_SETTLE_DURATION = 600; // ms |
| |
| private static final int[] LAYOUT_ATTRS = new int[] { |
| android.R.attr.layout_gravity |
| }; |
| |
| static class ItemInfo { |
| Object object; |
| int position; |
| boolean scrolling; |
| } |
| |
| private static final Comparator<ItemInfo> COMPARATOR = new Comparator<ItemInfo>(){ |
| @Override |
| public int compare(ItemInfo lhs, ItemInfo rhs) { |
| return lhs.position - rhs.position; |
| }}; |
| |
| private static final Interpolator sInterpolator = new Interpolator() { |
| public float getInterpolation(float t) { |
| // _o(t) = t * t * ((tension + 1) * t + tension) |
| // o(t) = _o(t - 1) + 1 |
| t -= 1.0f; |
| return t * t * t + 1.0f; |
| } |
| }; |
| |
| private final ArrayList<ItemInfo> mItems = new ArrayList<ItemInfo>(); |
| |
| private PagerAdapter mAdapter; |
| private int mCurItem; // Index of currently displayed page. |
| private int mRestoredCurItem = -1; |
| private Parcelable mRestoredAdapterState = null; |
| private ClassLoader mRestoredClassLoader = null; |
| private Scroller mScroller; |
| private PagerObserver mObserver; |
| |
| private int mPageMargin; |
| private Drawable mMarginDrawable; |
| private int mTopPageBounds; |
| private int mBottomPageBounds; |
| |
| private int mChildWidthMeasureSpec; |
| private int mChildHeightMeasureSpec; |
| private boolean mInLayout; |
| |
| private boolean mScrollingCacheEnabled; |
| |
| private boolean mPopulatePending; |
| private boolean mIsPopulating; |
| private boolean mScrolling; |
| private int mOffscreenPageLimit = DEFAULT_OFFSCREEN_PAGES; |
| |
| private boolean mIsBeingDragged; |
| private boolean mIsUnableToDrag; |
| private int mTouchSlop; |
| private float mInitialMotionX; |
| /** |
| * Position of the last motion event. |
| */ |
| private float mLastMotionX; |
| private float mLastMotionY; |
| /** |
| * ID of the active pointer. This is used to retain consistency during |
| * drags/flings if multiple pointers are used. |
| */ |
| private int mActivePointerId = INVALID_POINTER; |
| /** |
| * Sentinel value for no current active pointer. |
| * Used by {@link #mActivePointerId}. |
| */ |
| private static final int INVALID_POINTER = -1; |
| |
| /** |
| * Determines speed during touch scrolling |
| */ |
| private VelocityTracker mVelocityTracker; |
| private int mMinimumVelocity; |
| private int mMaximumVelocity; |
| private float mBaseLineFlingVelocity; |
| private float mFlingVelocityInfluence; |
| |
| private boolean mFakeDragging; |
| private long mFakeDragBeginTime; |
| |
| private EdgeEffectCompat mLeftEdge; |
| private EdgeEffectCompat mRightEdge; |
| |
| private boolean mFirstLayout = true; |
| private boolean mCalledSuper; |
| private int mDecorChildCount; |
| |
| private OnPageChangeListener mOnPageChangeListener; |
| private OnPageChangeListener mInternalPageChangeListener; |
| private OnAdapterChangeListener mAdapterChangeListener; |
| |
| /** |
| * Indicates that the pager is in an idle, settled state. The current page |
| * is fully in view and no animation is in progress. |
| */ |
| public static final int SCROLL_STATE_IDLE = 0; |
| |
| /** |
| * Indicates that the pager is currently being dragged by the user. |
| */ |
| public static final int SCROLL_STATE_DRAGGING = 1; |
| |
| /** |
| * Indicates that the pager is in the process of settling to a final position. |
| */ |
| public static final int SCROLL_STATE_SETTLING = 2; |
| |
| private int mScrollState = SCROLL_STATE_IDLE; |
| |
| /** |
| * Callback interface for responding to changing state of the selected page. |
| */ |
| public interface OnPageChangeListener { |
| |
| /** |
| * This method will be invoked when the current page is scrolled, either as part |
| * of a programmatically initiated smooth scroll or a user initiated touch scroll. |
| * |
| * @param position Position index of the first page currently being displayed. |
| * Page position+1 will be visible if positionOffset is nonzero. |
| * @param positionOffset Value from [0, 1) indicating the offset from the page at position. |
| * @param positionOffsetPixels Value in pixels indicating the offset from position. |
| */ |
| public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels); |
| |
| /** |
| * This method will be invoked when a new page becomes selected. Animation is not |
| * necessarily complete. |
| * |
| * @param position Position index of the new selected page. |
| */ |
| public void onPageSelected(int position); |
| |
| /** |
| * Called when the scroll state changes. Useful for discovering when the user |
| * begins dragging, when the pager is automatically settling to the current page, |
| * or when it is fully stopped/idle. |
| * |
| * @param state The new scroll state. |
| * @see ViewPager#SCROLL_STATE_IDLE |
| * @see ViewPager#SCROLL_STATE_DRAGGING |
| * @see ViewPager#SCROLL_STATE_SETTLING |
| */ |
| public void onPageScrollStateChanged(int state); |
| } |
| |
| /** |
| * Simple implementation of the {@link OnPageChangeListener} interface with stub |
| * implementations of each method. Extend this if you do not intend to override |
| * every method of {@link OnPageChangeListener}. |
| */ |
| public static class SimpleOnPageChangeListener implements OnPageChangeListener { |
| @Override |
| public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { |
| // This space for rent |
| } |
| |
| @Override |
| public void onPageSelected(int position) { |
| // This space for rent |
| } |
| |
| @Override |
| public void onPageScrollStateChanged(int state) { |
| // This space for rent |
| } |
| } |
| |
| /** |
| * Used internally to monitor when adapters are switched. |
| */ |
| interface OnAdapterChangeListener { |
| public void onAdapterChanged(PagerAdapter oldAdapter, PagerAdapter newAdapter); |
| } |
| |
| /** |
| * Used internally to tag special types of child views that should be added as |
| * pager decorations by default. |
| */ |
| interface Decor {} |
| |
| public ViewPager(Context context) { |
| super(context); |
| initViewPager(); |
| } |
| |
| public ViewPager(Context context, AttributeSet attrs) { |
| super(context, attrs); |
| initViewPager(); |
| } |
| |
| void initViewPager() { |
| setWillNotDraw(false); |
| setDescendantFocusability(FOCUS_AFTER_DESCENDANTS); |
| setFocusable(true); |
| final Context context = getContext(); |
| mScroller = new Scroller(context, sInterpolator); |
| final ViewConfiguration configuration = ViewConfiguration.get(context); |
| mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration); |
| mMinimumVelocity = configuration.getScaledMinimumFlingVelocity(); |
| mMaximumVelocity = configuration.getScaledMaximumFlingVelocity(); |
| mLeftEdge = new EdgeEffectCompat(context); |
| mRightEdge = new EdgeEffectCompat(context); |
| |
| float density = context.getResources().getDisplayMetrics().density; |
| mBaseLineFlingVelocity = 2500.0f * density; |
| mFlingVelocityInfluence = 0.4f; |
| } |
| |
| private void setScrollState(int newState) { |
| if (mScrollState == newState) { |
| return; |
| } |
| |
| mScrollState = newState; |
| if (mOnPageChangeListener != null) { |
| mOnPageChangeListener.onPageScrollStateChanged(newState); |
| } |
| } |
| |
| /** |
| * Set a PagerAdapter that will supply views for this pager as needed. |
| * |
| * @param adapter Adapter to use |
| */ |
| public void setAdapter(PagerAdapter adapter) { |
| if (mAdapter != null) { |
| mAdapter.unregisterDataSetObserver(mObserver); |
| mAdapter.startUpdate(this); |
| for (int i = 0; i < mItems.size(); i++) { |
| final ItemInfo ii = mItems.get(i); |
| mAdapter.destroyItem(this, ii.position, ii.object); |
| } |
| mAdapter.finishUpdate(this); |
| mItems.clear(); |
| removeNonDecorViews(); |
| mCurItem = 0; |
| scrollTo(0, 0); |
| } |
| |
| final PagerAdapter oldAdapter = mAdapter; |
| mAdapter = adapter; |
| |
| if (mAdapter != null) { |
| if (mObserver == null) { |
| mObserver = new PagerObserver(); |
| } |
| mAdapter.registerDataSetObserver(mObserver); |
| mPopulatePending = false; |
| if (mRestoredCurItem >= 0) { |
| mAdapter.restoreState(mRestoredAdapterState, mRestoredClassLoader); |
| setCurrentItemInternal(mRestoredCurItem, false, true); |
| mRestoredCurItem = -1; |
| mRestoredAdapterState = null; |
| mRestoredClassLoader = null; |
| } else { |
| populate(); |
| } |
| } |
| |
| if (mAdapterChangeListener != null && oldAdapter != adapter) { |
| mAdapterChangeListener.onAdapterChanged(oldAdapter, adapter); |
| } |
| } |
| |
| private void removeNonDecorViews() { |
| for (int i = 0; i < getChildCount(); i++) { |
| final View child = getChildAt(i); |
| final LayoutParams lp = (LayoutParams) child.getLayoutParams(); |
| if (!lp.isDecor) { |
| removeViewAt(i); |
| i--; |
| } |
| } |
| } |
| |
| /** |
| * Retrieve the current adapter supplying pages. |
| * |
| * @return The currently registered PagerAdapter |
| */ |
| public PagerAdapter getAdapter() { |
| return mAdapter; |
| } |
| |
| void setOnAdapterChangeListener(OnAdapterChangeListener listener) { |
| mAdapterChangeListener = listener; |
| } |
| |
| /** |
| * Set the currently selected page. If the ViewPager has already been through its first |
| * layout there will be a smooth animated transition between the current item and the |
| * specified item. |
| * |
| * @param item Item index to select |
| */ |
| public void setCurrentItem(int item) { |
| mPopulatePending = false; |
| setCurrentItemInternal(item, !mFirstLayout, false); |
| } |
| |
| /** |
| * Set the currently selected page. |
| * |
| * @param item Item index to select |
| * @param smoothScroll True to smoothly scroll to the new item, false to transition immediately |
| */ |
| public void setCurrentItem(int item, boolean smoothScroll) { |
| mPopulatePending = false; |
| setCurrentItemInternal(item, smoothScroll, false); |
| } |
| |
| public int getCurrentItem() { |
| return mCurItem; |
| } |
| |
| void setCurrentItemInternal(int item, boolean smoothScroll, boolean always) { |
| setCurrentItemInternal(item, smoothScroll, always, 0); |
| } |
| |
| void setCurrentItemInternal(int item, boolean smoothScroll, boolean always, int velocity) { |
| if (mAdapter == null || mAdapter.getCount() <= 0) { |
| setScrollingCacheEnabled(false); |
| return; |
| } |
| if (!always && mCurItem == item && mItems.size() != 0) { |
| setScrollingCacheEnabled(false); |
| return; |
| } |
| if (item < 0) { |
| item = 0; |
| } else if (item >= mAdapter.getCount()) { |
| item = mAdapter.getCount() - 1; |
| } |
| final int pageLimit = mOffscreenPageLimit; |
| if (item > (mCurItem + pageLimit) || item < (mCurItem - pageLimit)) { |
| // We are doing a jump by more than one page. To avoid |
| // glitches, we want to keep all current pages in the view |
| // until the scroll ends. |
| for (int i=0; i<mItems.size(); i++) { |
| mItems.get(i).scrolling = true; |
| } |
| } |
| final boolean dispatchSelected = mCurItem != item; |
| mCurItem = item; |
| populate(); |
| final int destX = (getWidth() + mPageMargin) * item; |
| if (smoothScroll) { |
| smoothScrollTo(destX, 0, velocity); |
| if (dispatchSelected && mOnPageChangeListener != null) { |
| mOnPageChangeListener.onPageSelected(item); |
| } |
| if (dispatchSelected && mInternalPageChangeListener != null) { |
| mInternalPageChangeListener.onPageSelected(item); |
| } |
| } else { |
| if (dispatchSelected && mOnPageChangeListener != null) { |
| mOnPageChangeListener.onPageSelected(item); |
| } |
| if (dispatchSelected && mInternalPageChangeListener != null) { |
| mInternalPageChangeListener.onPageSelected(item); |
| } |
| completeScroll(); |
| scrollTo(destX, 0); |
| } |
| } |
| |
| /** |
| * Set a listener that will be invoked whenever the page changes or is incrementally |
| * scrolled. See {@link OnPageChangeListener}. |
| * |
| * @param listener Listener to set |
| */ |
| public void setOnPageChangeListener(OnPageChangeListener listener) { |
| mOnPageChangeListener = listener; |
| } |
| |
| /** |
| * Set a separate OnPageChangeListener for internal use by the support library. |
| * |
| * @param listener Listener to set |
| * @return The old listener that was set, if any. |
| */ |
| OnPageChangeListener setInternalPageChangeListener(OnPageChangeListener listener) { |
| OnPageChangeListener oldListener = mInternalPageChangeListener; |
| mInternalPageChangeListener = listener; |
| return oldListener; |
| } |
| |
| /** |
| * Returns the number of pages that will be retained to either side of the |
| * current page in the view hierarchy in an idle state. Defaults to 1. |
| * |
| * @return How many pages will be kept offscreen on either side |
| * @see #setOffscreenPageLimit(int) |
| */ |
| public int getOffscreenPageLimit() { |
| return mOffscreenPageLimit; |
| } |
| |
| /** |
| * Set the number of pages that should be retained to either side of the |
| * current page in the view hierarchy in an idle state. Pages beyond this |
| * limit will be recreated from the adapter when needed. |
| * |
| * <p>This is offered as an optimization. If you know in advance the number |
| * of pages you will need to support or have lazy-loading mechanisms in place |
| * on your pages, tweaking this setting can have benefits in perceived smoothness |
| * of paging animations and interaction. If you have a small number of pages (3-4) |
| * that you can keep active all at once, less time will be spent in layout for |
| * newly created view subtrees as the user pages back and forth.</p> |
| * |
| * <p>You should keep this limit low, especially if your pages have complex layouts. |
| * This setting defaults to 1.</p> |
| * |
| * @param limit How many pages will be kept offscreen in an idle state. |
| */ |
| public void setOffscreenPageLimit(int limit) { |
| if (limit < DEFAULT_OFFSCREEN_PAGES) { |
| Log.w(TAG, "Requested offscreen page limit " + limit + " too small; defaulting to " + |
| DEFAULT_OFFSCREEN_PAGES); |
| limit = DEFAULT_OFFSCREEN_PAGES; |
| } |
| if (limit != mOffscreenPageLimit) { |
| mOffscreenPageLimit = limit; |
| populate(); |
| } |
| } |
| |
| /** |
| * Set the margin between pages. |
| * |
| * @param marginPixels Distance between adjacent pages in pixels |
| * @see #getPageMargin() |
| * @see #setPageMarginDrawable(Drawable) |
| * @see #setPageMarginDrawable(int) |
| */ |
| public void setPageMargin(int marginPixels) { |
| final int oldMargin = mPageMargin; |
| mPageMargin = marginPixels; |
| |
| final int width = getWidth(); |
| recomputeScrollPosition(width, width, marginPixels, oldMargin); |
| |
| requestLayout(); |
| } |
| |
| /** |
| * Return the margin between pages. |
| * |
| * @return The size of the margin in pixels |
| */ |
| public int getPageMargin() { |
| return mPageMargin; |
| } |
| |
| /** |
| * Set a drawable that will be used to fill the margin between pages. |
| * |
| * @param d Drawable to display between pages |
| */ |
| public void setPageMarginDrawable(Drawable d) { |
| mMarginDrawable = d; |
| if (d != null) refreshDrawableState(); |
| setWillNotDraw(d == null); |
| invalidate(); |
| } |
| |
| /** |
| * Set a drawable that will be used to fill the margin between pages. |
| * |
| * @param resId Resource ID of a drawable to display between pages |
| */ |
| public void setPageMarginDrawable(int resId) { |
| setPageMarginDrawable(getContext().getResources().getDrawable(resId)); |
| } |
| |
| @Override |
| protected boolean verifyDrawable(Drawable who) { |
| return super.verifyDrawable(who) || who == mMarginDrawable; |
| } |
| |
| @Override |
| protected void drawableStateChanged() { |
| super.drawableStateChanged(); |
| final Drawable d = mMarginDrawable; |
| if (d != null && d.isStateful()) { |
| d.setState(getDrawableState()); |
| } |
| } |
| |
| // We want the duration of the page snap animation to be influenced by the distance that |
| // the screen has to travel, however, we don't want this duration to be effected in a |
| // purely linear fashion. Instead, we use this method to moderate the effect that the distance |
| // of travel has on the overall snap duration. |
| float distanceInfluenceForSnapDuration(float f) { |
| f -= 0.5f; // center the values about 0. |
| f *= 0.3f * Math.PI / 2.0f; |
| return (float) Math.sin(f); |
| } |
| |
| /** |
| * Like {@link View#scrollBy}, but scroll smoothly instead of immediately. |
| * |
| * @param x the number of pixels to scroll by on the X axis |
| * @param y the number of pixels to scroll by on the Y axis |
| */ |
| void smoothScrollTo(int x, int y) { |
| smoothScrollTo(x, y, 0); |
| } |
| |
| /** |
| * Like {@link View#scrollBy}, but scroll smoothly instead of immediately. |
| * |
| * @param x the number of pixels to scroll by on the X axis |
| * @param y the number of pixels to scroll by on the Y axis |
| * @param velocity the velocity associated with a fling, if applicable. (0 otherwise) |
| */ |
| void smoothScrollTo(int x, int y, int velocity) { |
| if (getChildCount() == 0) { |
| // Nothing to do. |
| setScrollingCacheEnabled(false); |
| return; |
| } |
| int sx = getScrollX(); |
| int sy = getScrollY(); |
| int dx = x - sx; |
| int dy = y - sy; |
| if (dx == 0 && dy == 0) { |
| completeScroll(); |
| setScrollState(SCROLL_STATE_IDLE); |
| return; |
| } |
| |
| setScrollingCacheEnabled(true); |
| mScrolling = true; |
| setScrollState(SCROLL_STATE_SETTLING); |
| |
| final float pageDelta = (float) Math.abs(dx) / (getWidth() + mPageMargin); |
| int duration = (int) (pageDelta * 100); |
| |
| velocity = Math.abs(velocity); |
| if (velocity > 0) { |
| duration += (duration / (velocity / mBaseLineFlingVelocity)) * mFlingVelocityInfluence; |
| } else { |
| duration += 100; |
| } |
| duration = Math.min(duration, MAX_SETTLE_DURATION); |
| |
| mScroller.startScroll(sx, sy, dx, dy, duration); |
| invalidate(); |
| } |
| |
| void addNewItem(int position, int index) { |
| ItemInfo ii = new ItemInfo(); |
| ii.position = position; |
| ii.object = mAdapter.instantiateItem(this, position); |
| if (index < 0) { |
| mItems.add(ii); |
| } else { |
| mItems.add(index, ii); |
| } |
| } |
| |
| void dataSetChanged() { |
| // This method only gets called if our observer is attached, so mAdapter is non-null. |
| |
| boolean needPopulate = mItems.size() < 3 && mItems.size() < mAdapter.getCount(); |
| int newCurrItem = -1; |
| |
| boolean isUpdating = false; |
| for (int i = 0; i < mItems.size(); i++) { |
| final ItemInfo ii = mItems.get(i); |
| final int newPos = mAdapter.getItemPosition(ii.object); |
| |
| if (newPos == PagerAdapter.POSITION_UNCHANGED) { |
| continue; |
| } |
| |
| if (newPos == PagerAdapter.POSITION_NONE) { |
| mItems.remove(i); |
| i--; |
| |
| if (!isUpdating) { |
| mAdapter.startUpdate(this); |
| isUpdating = true; |
| } |
| |
| mAdapter.destroyItem(this, ii.position, ii.object); |
| needPopulate = true; |
| |
| if (mCurItem == ii.position) { |
| // Keep the current item in the valid range |
| newCurrItem = Math.max(0, Math.min(mCurItem, mAdapter.getCount() - 1)); |
| } |
| continue; |
| } |
| |
| if (ii.position != newPos) { |
| if (ii.position == mCurItem) { |
| // Our current item changed position. Follow it. |
| newCurrItem = newPos; |
| } |
| |
| ii.position = newPos; |
| needPopulate = true; |
| } |
| } |
| |
| if (isUpdating) { |
| mAdapter.finishUpdate(this); |
| } |
| |
| Collections.sort(mItems, COMPARATOR); |
| |
| if (newCurrItem >= 0) { |
| // TODO This currently causes a jump. |
| setCurrentItemInternal(newCurrItem, false, true); |
| needPopulate = true; |
| } |
| if (needPopulate) { |
| populate(); |
| requestLayout(); |
| } |
| } |
| |
| void populate() { |
| if (mAdapter == null) { |
| return; |
| } |
| |
| // Bail now if we are waiting to populate. This is to hold off |
| // on creating views from the time the user releases their finger to |
| // fling to a new position until we have finished the scroll to |
| // that position, avoiding glitches from happening at that point. |
| if (mPopulatePending) { |
| if (DEBUG) Log.i(TAG, "populate is pending, skipping for now..."); |
| return; |
| } |
| |
| // Also, don't populate until we are attached to a window. This is to |
| // avoid trying to populate before we have restored our view hierarchy |
| // state and conflicting with what is restored. |
| if (getWindowToken() == null) { |
| return; |
| } |
| |
| mIsPopulating = true; |
| mAdapter.startUpdate(this); |
| |
| final int pageLimit = mOffscreenPageLimit; |
| final int startPos = Math.max(0, mCurItem - pageLimit); |
| final int N = mAdapter.getCount(); |
| final int endPos = Math.min(N-1, mCurItem + pageLimit); |
| |
| if (DEBUG) Log.v(TAG, "populating: startPos=" + startPos + " endPos=" + endPos); |
| |
| // Add and remove pages in the existing list. |
| int lastPos = -1; |
| for (int i=0; i<mItems.size(); i++) { |
| ItemInfo ii = mItems.get(i); |
| if ((ii.position < startPos || ii.position > endPos) && !ii.scrolling) { |
| if (DEBUG) Log.i(TAG, "removing: " + ii.position + " @ " + i); |
| mItems.remove(i); |
| i--; |
| mAdapter.destroyItem(this, ii.position, ii.object); |
| } else if (lastPos < endPos && ii.position > startPos) { |
| // The next item is outside of our range, but we have a gap |
| // between it and the last item where we want to have a page |
| // shown. Fill in the gap. |
| lastPos++; |
| if (lastPos < startPos) { |
| lastPos = startPos; |
| } |
| while (lastPos <= endPos && lastPos < ii.position) { |
| if (DEBUG) Log.i(TAG, "inserting: " + lastPos + " @ " + i); |
| addNewItem(lastPos, i); |
| lastPos++; |
| i++; |
| } |
| } |
| lastPos = ii.position; |
| } |
| |
| // Add any new pages we need at the end. |
| lastPos = mItems.size() > 0 ? mItems.get(mItems.size()-1).position : -1; |
| if (lastPos < endPos) { |
| lastPos++; |
| lastPos = lastPos > startPos ? lastPos : startPos; |
| while (lastPos <= endPos) { |
| if (DEBUG) Log.i(TAG, "appending: " + lastPos); |
| addNewItem(lastPos, -1); |
| lastPos++; |
| } |
| } |
| |
| if (DEBUG) { |
| Log.i(TAG, "Current page list:"); |
| for (int i=0; i<mItems.size(); i++) { |
| Log.i(TAG, "#" + i + ": page " + mItems.get(i).position); |
| } |
| } |
| |
| ItemInfo curItem = null; |
| for (int i=0; i<mItems.size(); i++) { |
| if (mItems.get(i).position == mCurItem) { |
| curItem = mItems.get(i); |
| break; |
| } |
| } |
| mAdapter.setPrimaryItem(this, mCurItem, curItem != null ? curItem.object : null); |
| |
| mAdapter.finishUpdate(this); |
| mIsPopulating = false; |
| |
| if (hasFocus()) { |
| View currentFocused = findFocus(); |
| ItemInfo ii = currentFocused != null ? infoForAnyChild(currentFocused) : null; |
| if (ii == null || ii.position != mCurItem) { |
| for (int i=0; i<getChildCount(); i++) { |
| View child = getChildAt(i); |
| ii = infoForChild(child); |
| if (ii != null && ii.position == mCurItem) { |
| if (child.requestFocus(FOCUS_FORWARD)) { |
| break; |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| public static class SavedState extends BaseSavedState { |
| int position; |
| Parcelable adapterState; |
| ClassLoader loader; |
| |
| public SavedState(Parcelable superState) { |
| super(superState); |
| } |
| |
| @Override |
| public void writeToParcel(Parcel out, int flags) { |
| super.writeToParcel(out, flags); |
| out.writeInt(position); |
| out.writeParcelable(adapterState, flags); |
| } |
| |
| @Override |
| public String toString() { |
| return "FragmentPager.SavedState{" |
| + Integer.toHexString(System.identityHashCode(this)) |
| + " position=" + position + "}"; |
| } |
| |
| public static final Parcelable.Creator<SavedState> CREATOR |
| = ParcelableCompat.newCreator(new ParcelableCompatCreatorCallbacks<SavedState>() { |
| @Override |
| public SavedState createFromParcel(Parcel in, ClassLoader loader) { |
| return new SavedState(in, loader); |
| } |
| @Override |
| public SavedState[] newArray(int size) { |
| return new SavedState[size]; |
| } |
| }); |
| |
| SavedState(Parcel in, ClassLoader loader) { |
| super(in); |
| if (loader == null) { |
| loader = getClass().getClassLoader(); |
| } |
| position = in.readInt(); |
| adapterState = in.readParcelable(loader); |
| this.loader = loader; |
| } |
| } |
| |
| @Override |
| public Parcelable onSaveInstanceState() { |
| Parcelable superState = super.onSaveInstanceState(); |
| SavedState ss = new SavedState(superState); |
| ss.position = mCurItem; |
| if (mAdapter != null) { |
| ss.adapterState = mAdapter.saveState(); |
| } |
| return ss; |
| } |
| |
| @Override |
| public void onRestoreInstanceState(Parcelable state) { |
| if (!(state instanceof SavedState)) { |
| super.onRestoreInstanceState(state); |
| return; |
| } |
| |
| SavedState ss = (SavedState)state; |
| super.onRestoreInstanceState(ss.getSuperState()); |
| |
| if (mAdapter != null) { |
| mAdapter.restoreState(ss.adapterState, ss.loader); |
| setCurrentItemInternal(ss.position, false, true); |
| } else { |
| mRestoredCurItem = ss.position; |
| mRestoredAdapterState = ss.adapterState; |
| mRestoredClassLoader = ss.loader; |
| } |
| } |
| |
| @Override |
| public void addView(View child, int index, ViewGroup.LayoutParams params) { |
| if (!checkLayoutParams(params)) { |
| params = generateLayoutParams(params); |
| } |
| final LayoutParams lp = (LayoutParams) params; |
| lp.isDecor |= child instanceof Decor; |
| if (mInLayout) { |
| if (lp != null && lp.isDecor) { |
| throw new IllegalStateException("Cannot add pager decor view during layout"); |
| } |
| addViewInLayout(child, index, params); |
| child.measure(mChildWidthMeasureSpec, mChildHeightMeasureSpec); |
| } else { |
| super.addView(child, index, params); |
| } |
| |
| if (USE_CACHE) { |
| if (child.getVisibility() != GONE) { |
| child.setDrawingCacheEnabled(mScrollingCacheEnabled); |
| } else { |
| child.setDrawingCacheEnabled(false); |
| } |
| } |
| } |
| |
| ItemInfo infoForChild(View child) { |
| for (int i=0; i<mItems.size(); i++) { |
| ItemInfo ii = mItems.get(i); |
| if (mAdapter.isViewFromObject(child, ii.object)) { |
| return ii; |
| } |
| } |
| return null; |
| } |
| |
| ItemInfo infoForAnyChild(View child) { |
| ViewParent parent; |
| while ((parent=child.getParent()) != this) { |
| if (parent == null || !(parent instanceof View)) { |
| return null; |
| } |
| child = (View)parent; |
| } |
| return infoForChild(child); |
| } |
| |
| @Override |
| protected void onAttachedToWindow() { |
| super.onAttachedToWindow(); |
| mFirstLayout = true; |
| } |
| |
| @Override |
| protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { |
| // For simple implementation, or internal size is always 0. |
| // We depend on the container to specify the layout size of |
| // our view. We can't really know what it is since we will be |
| // adding and removing different arbitrary views and do not |
| // want the layout to change as this happens. |
| setMeasuredDimension(getDefaultSize(0, widthMeasureSpec), |
| getDefaultSize(0, heightMeasureSpec)); |
| |
| // Children are just made to fill our space. |
| int childWidthSize = getMeasuredWidth() - getPaddingLeft() - getPaddingRight(); |
| int childHeightSize = getMeasuredHeight() - getPaddingTop() - getPaddingBottom(); |
| |
| /* |
| * Make sure all children have been properly measured. Decor views first. |
| * Right now we cheat and make this less complicated by assuming decor |
| * views won't intersect. We will pin to edges based on gravity. |
| */ |
| int size = getChildCount(); |
| for (int i = 0; i < size; ++i) { |
| final View child = getChildAt(i); |
| if (child.getVisibility() != GONE) { |
| final LayoutParams lp = (LayoutParams) child.getLayoutParams(); |
| if (lp != null && lp.isDecor) { |
| final int hgrav = lp.gravity & Gravity.HORIZONTAL_GRAVITY_MASK; |
| final int vgrav = lp.gravity & Gravity.VERTICAL_GRAVITY_MASK; |
| Log.d(TAG, "gravity: " + lp.gravity + " hgrav: " + hgrav + " vgrav: " + vgrav); |
| int widthMode = MeasureSpec.AT_MOST; |
| int heightMode = MeasureSpec.AT_MOST; |
| boolean consumeVertical = vgrav == Gravity.TOP || vgrav == Gravity.BOTTOM; |
| boolean consumeHorizontal = hgrav == Gravity.LEFT || hgrav == Gravity.RIGHT; |
| |
| if (consumeVertical) { |
| widthMode = MeasureSpec.EXACTLY; |
| } else if (consumeHorizontal) { |
| heightMode = MeasureSpec.EXACTLY; |
| } |
| |
| final int widthSpec = MeasureSpec.makeMeasureSpec(childWidthSize, widthMode); |
| final int heightSpec = MeasureSpec.makeMeasureSpec(childHeightSize, heightMode); |
| child.measure(widthSpec, heightSpec); |
| |
| if (consumeVertical) { |
| childHeightSize -= child.getMeasuredHeight(); |
| } else if (consumeHorizontal) { |
| childWidthSize -= child.getMeasuredWidth(); |
| } |
| } |
| } |
| } |
| |
| mChildWidthMeasureSpec = MeasureSpec.makeMeasureSpec(childWidthSize, MeasureSpec.EXACTLY); |
| mChildHeightMeasureSpec = MeasureSpec.makeMeasureSpec(childHeightSize, MeasureSpec.EXACTLY); |
| |
| // Make sure we have created all fragments that we need to have shown. |
| mInLayout = true; |
| populate(); |
| mInLayout = false; |
| |
| // Page views next. |
| size = getChildCount(); |
| for (int i = 0; i < size; ++i) { |
| final View child = getChildAt(i); |
| if (child.getVisibility() != GONE) { |
| if (DEBUG) Log.v(TAG, "Measuring #" + i + " " + child |
| + ": " + mChildWidthMeasureSpec); |
| |
| final LayoutParams lp = (LayoutParams) child.getLayoutParams(); |
| if (lp == null || !lp.isDecor) { |
| child.measure(mChildWidthMeasureSpec, mChildHeightMeasureSpec); |
| } |
| } |
| } |
| } |
| |
| @Override |
| protected void onSizeChanged(int w, int h, int oldw, int oldh) { |
| super.onSizeChanged(w, h, oldw, oldh); |
| |
| // Make sure scroll position is set correctly. |
| if (w != oldw) { |
| recomputeScrollPosition(w, oldw, mPageMargin, mPageMargin); |
| } |
| } |
| |
| private void recomputeScrollPosition(int width, int oldWidth, int margin, int oldMargin) { |
| final int widthWithMargin = width + margin; |
| if (oldWidth > 0) { |
| final int oldScrollPos = getScrollX(); |
| final int oldwwm = oldWidth + oldMargin; |
| final int oldScrollItem = oldScrollPos / oldwwm; |
| final float scrollOffset = (float) (oldScrollPos % oldwwm) / oldwwm; |
| final int scrollPos = (int) ((oldScrollItem + scrollOffset) * widthWithMargin); |
| scrollTo(scrollPos, getScrollY()); |
| if (!mScroller.isFinished()) { |
| // We now return to your regularly scheduled scroll, already in progress. |
| final int newDuration = mScroller.getDuration() - mScroller.timePassed(); |
| mScroller.startScroll(scrollPos, 0, mCurItem * widthWithMargin, 0, newDuration); |
| } |
| } else { |
| int scrollPos = mCurItem * widthWithMargin; |
| if (scrollPos != getScrollX()) { |
| completeScroll(); |
| scrollTo(scrollPos, getScrollY()); |
| } |
| } |
| } |
| |
| @Override |
| protected void onLayout(boolean changed, int l, int t, int r, int b) { |
| mInLayout = true; |
| populate(); |
| mInLayout = false; |
| |
| final int count = getChildCount(); |
| int width = r - l; |
| int height = b - t; |
| int paddingLeft = getPaddingLeft(); |
| int paddingTop = getPaddingTop(); |
| int paddingRight = getPaddingRight(); |
| int paddingBottom = getPaddingBottom(); |
| final int scrollX = getScrollX(); |
| |
| int decorCount = 0; |
| |
| for (int i = 0; i < count; i++) { |
| final View child = getChildAt(i); |
| if (child.getVisibility() != GONE) { |
| final LayoutParams lp = (LayoutParams) child.getLayoutParams(); |
| ItemInfo ii; |
| int childLeft = 0; |
| int childTop = 0; |
| if (lp.isDecor) { |
| final int hgrav = lp.gravity & Gravity.HORIZONTAL_GRAVITY_MASK; |
| final int vgrav = lp.gravity & Gravity.VERTICAL_GRAVITY_MASK; |
| switch (hgrav) { |
| default: |
| childLeft = paddingLeft; |
| break; |
| case Gravity.LEFT: |
| childLeft = paddingLeft; |
| paddingLeft += child.getMeasuredWidth(); |
| break; |
| case Gravity.CENTER_HORIZONTAL: |
| childLeft = Math.max((width - child.getMeasuredWidth()) / 2, |
| paddingLeft); |
| break; |
| case Gravity.RIGHT: |
| childLeft = width - paddingRight - child.getMeasuredWidth(); |
| paddingRight += child.getMeasuredWidth(); |
| break; |
| } |
| switch (vgrav) { |
| default: |
| childTop = paddingTop; |
| break; |
| case Gravity.TOP: |
| childTop = paddingTop; |
| paddingTop += child.getMeasuredHeight(); |
| break; |
| case Gravity.CENTER_VERTICAL: |
| childTop = Math.max((height - child.getMeasuredHeight()) / 2, |
| paddingTop); |
| break; |
| case Gravity.BOTTOM: |
| childTop = height - paddingBottom - child.getMeasuredHeight(); |
| paddingBottom += child.getMeasuredHeight(); |
| break; |
| } |
| childLeft += scrollX; |
| decorCount++; |
| child.layout(childLeft, childTop, |
| childLeft + child.getMeasuredWidth(), |
| childTop + child.getMeasuredHeight()); |
| } else if ((ii = infoForChild(child)) != null) { |
| int loff = (width + mPageMargin) * ii.position; |
| childLeft = paddingLeft + loff; |
| childTop = paddingTop; |
| if (DEBUG) Log.v(TAG, "Positioning #" + i + " " + child + " f=" + ii.object |
| + ":" + childLeft + "," + childTop + " " + child.getMeasuredWidth() |
| + "x" + child.getMeasuredHeight()); |
| child.layout(childLeft, childTop, |
| childLeft + child.getMeasuredWidth(), |
| childTop + child.getMeasuredHeight()); |
| } |
| } |
| } |
| mTopPageBounds = paddingTop; |
| mBottomPageBounds = height - paddingBottom; |
| mDecorChildCount = decorCount; |
| mFirstLayout = false; |
| } |
| |
| @Override |
| public void computeScroll() { |
| if (DEBUG) Log.i(TAG, "computeScroll: finished=" + mScroller.isFinished()); |
| if (!mScroller.isFinished()) { |
| if (mScroller.computeScrollOffset()) { |
| if (DEBUG) Log.i(TAG, "computeScroll: still scrolling"); |
| int oldX = getScrollX(); |
| int oldY = getScrollY(); |
| int x = mScroller.getCurrX(); |
| int y = mScroller.getCurrY(); |
| |
| if (oldX != x || oldY != y) { |
| scrollTo(x, y); |
| pageScrolled(x); |
| } |
| |
| // Keep on drawing until the animation has finished. |
| invalidate(); |
| return; |
| } |
| } |
| |
| // Done with scroll, clean up state. |
| completeScroll(); |
| } |
| |
| private void pageScrolled(int xpos) { |
| final int widthWithMargin = getWidth() + mPageMargin; |
| final int position = xpos / widthWithMargin; |
| final int offsetPixels = xpos % widthWithMargin; |
| final float offset = (float) offsetPixels / widthWithMargin; |
| |
| mCalledSuper = false; |
| onPageScrolled(position, offset, offsetPixels); |
| if (!mCalledSuper) { |
| throw new IllegalStateException( |
| "onPageScrolled did not call superclass implementation"); |
| } |
| } |
| |
| /** |
| * This method will be invoked when the current page is scrolled, either as part |
| * of a programmatically initiated smooth scroll or a user initiated touch scroll. |
| * If you override this method you must call through to the superclass implementation |
| * (e.g. super.onPageScrolled(position, offset, offsetPixels)) before onPageScrolled |
| * returns. |
| * |
| * @param position Position index of the first page currently being displayed. |
| * Page position+1 will be visible if positionOffset is nonzero. |
| * @param offset Value from [0, 1) indicating the offset from the page at position. |
| * @param offsetPixels Value in pixels indicating the offset from position. |
| */ |
| protected void onPageScrolled(int position, float offset, int offsetPixels) { |
| // Offset any decor views if needed - keep them on-screen at all times. |
| if (mDecorChildCount > 0) { |
| final int scrollX = getScrollX(); |
| int paddingLeft = getPaddingLeft(); |
| int paddingRight = getPaddingRight(); |
| final int width = getWidth(); |
| final int childCount = getChildCount(); |
| for (int i = 0; i < childCount; i++) { |
| final View child = getChildAt(i); |
| final LayoutParams lp = (LayoutParams) child.getLayoutParams(); |
| if (!lp.isDecor) continue; |
| |
| final int hgrav = lp.gravity & Gravity.HORIZONTAL_GRAVITY_MASK; |
| int childLeft = 0; |
| switch (hgrav) { |
| default: |
| childLeft = paddingLeft; |
| break; |
| case Gravity.LEFT: |
| childLeft = paddingLeft; |
| paddingLeft += child.getWidth(); |
| break; |
| case Gravity.CENTER_HORIZONTAL: |
| childLeft = Math.max((width - child.getMeasuredWidth()) / 2, |
| paddingLeft); |
| break; |
| case Gravity.RIGHT: |
| childLeft = width - paddingRight - child.getMeasuredWidth(); |
| paddingRight += child.getMeasuredWidth(); |
| break; |
| } |
| childLeft += scrollX; |
| |
| final int childOffset = childLeft - child.getLeft(); |
| if (childOffset != 0) { |
| child.offsetLeftAndRight(childOffset); |
| } |
| } |
| } |
| |
| if (mOnPageChangeListener != null) { |
| mOnPageChangeListener.onPageScrolled(position, offset, offsetPixels); |
| } |
| if (mInternalPageChangeListener != null) { |
| mInternalPageChangeListener.onPageScrolled(position, offset, offsetPixels); |
| } |
| mCalledSuper = true; |
| } |
| |
| private void completeScroll() { |
| boolean needPopulate = mScrolling; |
| if (needPopulate) { |
| // Done with scroll, no longer want to cache view drawing. |
| setScrollingCacheEnabled(false); |
| mScroller.abortAnimation(); |
| int oldX = getScrollX(); |
| int oldY = getScrollY(); |
| int x = mScroller.getCurrX(); |
| int y = mScroller.getCurrY(); |
| if (oldX != x || oldY != y) { |
| scrollTo(x, y); |
| } |
| setScrollState(SCROLL_STATE_IDLE); |
| } |
| mPopulatePending = false; |
| mScrolling = false; |
| for (int i=0; i<mItems.size(); i++) { |
| ItemInfo ii = mItems.get(i); |
| if (ii.scrolling) { |
| needPopulate = true; |
| ii.scrolling = false; |
| } |
| } |
| if (needPopulate) { |
| populate(); |
| } |
| } |
| |
| @Override |
| public boolean onInterceptTouchEvent(MotionEvent ev) { |
| /* |
| * This method JUST determines whether we want to intercept the motion. |
| * If we return true, onMotionEvent will be called and we do the actual |
| * scrolling there. |
| */ |
| |
| final int action = ev.getAction() & MotionEventCompat.ACTION_MASK; |
| |
| // Always take care of the touch gesture being complete. |
| if (action == MotionEvent.ACTION_CANCEL || action == MotionEvent.ACTION_UP) { |
| // Release the drag. |
| if (DEBUG) Log.v(TAG, "Intercept done!"); |
| mIsBeingDragged = false; |
| mIsUnableToDrag = false; |
| mActivePointerId = INVALID_POINTER; |
| if (mVelocityTracker != null) { |
| mVelocityTracker.recycle(); |
| mVelocityTracker = null; |
| } |
| return false; |
| } |
| |
| // Nothing more to do here if we have decided whether or not we |
| // are dragging. |
| if (action != MotionEvent.ACTION_DOWN) { |
| if (mIsBeingDragged) { |
| if (DEBUG) Log.v(TAG, "Intercept returning true!"); |
| return true; |
| } |
| if (mIsUnableToDrag) { |
| if (DEBUG) Log.v(TAG, "Intercept returning false!"); |
| return false; |
| } |
| } |
| |
| switch (action) { |
| case MotionEvent.ACTION_MOVE: { |
| /* |
| * mIsBeingDragged == false, otherwise the shortcut would have caught it. Check |
| * whether the user has moved far enough from his original down touch. |
| */ |
| |
| /* |
| * Locally do absolute value. mLastMotionY is set to the y value |
| * of the down event. |
| */ |
| final int activePointerId = mActivePointerId; |
| if (activePointerId == INVALID_POINTER) { |
| // If we don't have a valid id, the touch down wasn't on content. |
| break; |
| } |
| |
| final int pointerIndex = MotionEventCompat.findPointerIndex(ev, activePointerId); |
| final float x = MotionEventCompat.getX(ev, pointerIndex); |
| final float dx = x - mLastMotionX; |
| final float xDiff = Math.abs(dx); |
| final float y = MotionEventCompat.getY(ev, pointerIndex); |
| final float yDiff = Math.abs(y - mLastMotionY); |
| final int scrollX = getScrollX(); |
| if (DEBUG) Log.v(TAG, "Moved x to " + x + "," + y + " diff=" + xDiff + "," + yDiff); |
| |
| if (canScroll(this, false, (int) dx, (int) x, (int) y)) { |
| // Nested view has scrollable area under this point. Let it be handled there. |
| mInitialMotionX = mLastMotionX = x; |
| mLastMotionY = y; |
| return false; |
| } |
| if (xDiff > mTouchSlop && xDiff > yDiff) { |
| if (DEBUG) Log.v(TAG, "Starting drag!"); |
| mIsBeingDragged = true; |
| setScrollState(SCROLL_STATE_DRAGGING); |
| mLastMotionX = x; |
| setScrollingCacheEnabled(true); |
| } else { |
| if (yDiff > mTouchSlop) { |
| // The finger has moved enough in the vertical |
| // direction to be counted as a drag... abort |
| // any attempt to drag horizontally, to work correctly |
| // with children that have scrolling containers. |
| if (DEBUG) Log.v(TAG, "Starting unable to drag!"); |
| mIsUnableToDrag = true; |
| } |
| } |
| break; |
| } |
| |
| case MotionEvent.ACTION_DOWN: { |
| /* |
| * Remember location of down touch. |
| * ACTION_DOWN always refers to pointer index 0. |
| */ |
| mLastMotionX = mInitialMotionX = ev.getX(); |
| mLastMotionY = ev.getY(); |
| mActivePointerId = MotionEventCompat.getPointerId(ev, 0); |
| |
| if (mScrollState == SCROLL_STATE_SETTLING) { |
| // Let the user 'catch' the pager as it animates. |
| mIsBeingDragged = true; |
| mIsUnableToDrag = false; |
| setScrollState(SCROLL_STATE_DRAGGING); |
| } else { |
| completeScroll(); |
| mIsBeingDragged = false; |
| mIsUnableToDrag = false; |
| } |
| |
| if (DEBUG) Log.v(TAG, "Down at " + mLastMotionX + "," + mLastMotionY |
| + " mIsBeingDragged=" + mIsBeingDragged |
| + "mIsUnableToDrag=" + mIsUnableToDrag); |
| break; |
| } |
| |
| case MotionEventCompat.ACTION_POINTER_UP: |
| onSecondaryPointerUp(ev); |
| break; |
| } |
| |
| if (!mIsBeingDragged) { |
| // Track the velocity as long as we aren't dragging. |
| // Once we start a real drag we will track in onTouchEvent. |
| if (mVelocityTracker == null) { |
| mVelocityTracker = VelocityTracker.obtain(); |
| } |
| mVelocityTracker.addMovement(ev); |
| } |
| |
| /* |
| * The only time we want to intercept motion events is if we are in the |
| * drag mode. |
| */ |
| return mIsBeingDragged; |
| } |
| |
| @Override |
| public boolean onTouchEvent(MotionEvent ev) { |
| if (mFakeDragging) { |
| // A fake drag is in progress already, ignore this real one |
| // but still eat the touch events. |
| // (It is likely that the user is multi-touching the screen.) |
| return true; |
| } |
| |
| if (ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0) { |
| // Don't handle edge touches immediately -- they may actually belong to one of our |
| // descendants. |
| return false; |
| } |
| |
| if (mAdapter == null || mAdapter.getCount() == 0) { |
| // Nothing to present or scroll; nothing to touch. |
| return false; |
| } |
| |
| if (mVelocityTracker == null) { |
| mVelocityTracker = VelocityTracker.obtain(); |
| } |
| mVelocityTracker.addMovement(ev); |
| |
| final int action = ev.getAction(); |
| boolean needsInvalidate = false; |
| |
| switch (action & MotionEventCompat.ACTION_MASK) { |
| case MotionEvent.ACTION_DOWN: { |
| /* |
| * If being flinged and user touches, stop the fling. isFinished |
| * will be false if being flinged. |
| */ |
| completeScroll(); |
| |
| // Remember where the motion event started |
| mLastMotionX = mInitialMotionX = ev.getX(); |
| mActivePointerId = MotionEventCompat.getPointerId(ev, 0); |
| break; |
| } |
| case MotionEvent.ACTION_MOVE: |
| if (!mIsBeingDragged) { |
| final int pointerIndex = MotionEventCompat.findPointerIndex(ev, mActivePointerId); |
| final float x = MotionEventCompat.getX(ev, pointerIndex); |
| final float xDiff = Math.abs(x - mLastMotionX); |
| final float y = MotionEventCompat.getY(ev, pointerIndex); |
| final float yDiff = Math.abs(y - mLastMotionY); |
| if (DEBUG) Log.v(TAG, "Moved x to " + x + "," + y + " diff=" + xDiff + "," + yDiff); |
| if (xDiff > mTouchSlop && xDiff > yDiff) { |
| if (DEBUG) Log.v(TAG, "Starting drag!"); |
| mIsBeingDragged = true; |
| mLastMotionX = x; |
| setScrollState(SCROLL_STATE_DRAGGING); |
| setScrollingCacheEnabled(true); |
| } |
| } |
| if (mIsBeingDragged) { |
| // Scroll to follow the motion event |
| final int activePointerIndex = MotionEventCompat.findPointerIndex( |
| ev, mActivePointerId); |
| final float x = MotionEventCompat.getX(ev, activePointerIndex); |
| final float deltaX = mLastMotionX - x; |
| mLastMotionX = x; |
| float oldScrollX = getScrollX(); |
| float scrollX = oldScrollX + deltaX; |
| final int width = getWidth(); |
| final int widthWithMargin = width + mPageMargin; |
| |
| final int lastItemIndex = mAdapter.getCount() - 1; |
| final float leftBound = Math.max(0, (mCurItem - 1) * widthWithMargin); |
| final float rightBound = |
| Math.min(mCurItem + 1, lastItemIndex) * widthWithMargin; |
| if (scrollX < leftBound) { |
| if (leftBound == 0) { |
| float over = -scrollX; |
| needsInvalidate = mLeftEdge.onPull(over / width); |
| } |
| scrollX = leftBound; |
| } else if (scrollX > rightBound) { |
| if (rightBound == lastItemIndex * widthWithMargin) { |
| float over = scrollX - rightBound; |
| needsInvalidate = mRightEdge.onPull(over / width); |
| } |
| scrollX = rightBound; |
| } |
| // Don't lose the rounded component |
| mLastMotionX += scrollX - (int) scrollX; |
| scrollTo((int) scrollX, getScrollY()); |
| pageScrolled((int) scrollX); |
| } |
| break; |
| case MotionEvent.ACTION_UP: |
| if (mIsBeingDragged) { |
| final VelocityTracker velocityTracker = mVelocityTracker; |
| velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); |
| int initialVelocity = (int) VelocityTrackerCompat.getXVelocity( |
| velocityTracker, mActivePointerId); |
| mPopulatePending = true; |
| final int widthWithMargin = getWidth() + mPageMargin; |
| final int scrollX = getScrollX(); |
| final int currentPage = scrollX / widthWithMargin; |
| int nextPage = initialVelocity > 0 ? currentPage : currentPage + 1; |
| setCurrentItemInternal(nextPage, true, true, initialVelocity); |
| |
| mActivePointerId = INVALID_POINTER; |
| endDrag(); |
| needsInvalidate = mLeftEdge.onRelease() | mRightEdge.onRelease(); |
| } |
| break; |
| case MotionEvent.ACTION_CANCEL: |
| if (mIsBeingDragged) { |
| setCurrentItemInternal(mCurItem, true, true); |
| mActivePointerId = INVALID_POINTER; |
| endDrag(); |
| needsInvalidate = mLeftEdge.onRelease() | mRightEdge.onRelease(); |
| } |
| break; |
| case MotionEventCompat.ACTION_POINTER_DOWN: { |
| final int index = MotionEventCompat.getActionIndex(ev); |
| final float x = MotionEventCompat.getX(ev, index); |
| mLastMotionX = x; |
| mActivePointerId = MotionEventCompat.getPointerId(ev, index); |
| break; |
| } |
| case MotionEventCompat.ACTION_POINTER_UP: |
| onSecondaryPointerUp(ev); |
| mLastMotionX = MotionEventCompat.getX(ev, |
| MotionEventCompat.findPointerIndex(ev, mActivePointerId)); |
| break; |
| } |
| if (needsInvalidate) { |
| invalidate(); |
| } |
| return true; |
| } |
| |
| @Override |
| public void draw(Canvas canvas) { |
| super.draw(canvas); |
| boolean needsInvalidate = false; |
| |
| final int overScrollMode = ViewCompat.getOverScrollMode(this); |
| if (overScrollMode == ViewCompat.OVER_SCROLL_ALWAYS || |
| (overScrollMode == ViewCompat.OVER_SCROLL_IF_CONTENT_SCROLLS && |
| mAdapter != null && mAdapter.getCount() > 1)) { |
| if (!mLeftEdge.isFinished()) { |
| final int restoreCount = canvas.save(); |
| final int height = getHeight() - getPaddingTop() - getPaddingBottom(); |
| |
| canvas.rotate(270); |
| canvas.translate(-height + getPaddingTop(), 0); |
| mLeftEdge.setSize(height, getWidth()); |
| needsInvalidate |= mLeftEdge.draw(canvas); |
| canvas.restoreToCount(restoreCount); |
| } |
| if (!mRightEdge.isFinished()) { |
| final int restoreCount = canvas.save(); |
| final int width = getWidth(); |
| final int height = getHeight() - getPaddingTop() - getPaddingBottom(); |
| final int itemCount = mAdapter != null ? mAdapter.getCount() : 1; |
| |
| canvas.rotate(90); |
| canvas.translate(-getPaddingTop(), |
| -itemCount * (width + mPageMargin) + mPageMargin); |
| mRightEdge.setSize(height, width); |
| needsInvalidate |= mRightEdge.draw(canvas); |
| canvas.restoreToCount(restoreCount); |
| } |
| } else { |
| mLeftEdge.finish(); |
| mRightEdge.finish(); |
| } |
| |
| if (needsInvalidate) { |
| // Keep animating |
| invalidate(); |
| } |
| } |
| |
| @Override |
| protected void onDraw(Canvas canvas) { |
| super.onDraw(canvas); |
| |
| // Draw the margin drawable if needed. |
| if (mPageMargin > 0 && mMarginDrawable != null) { |
| final int scrollX = getScrollX(); |
| final int width = getWidth(); |
| final int offset = scrollX % (width + mPageMargin); |
| if (offset != 0) { |
| // Pages fit completely when settled; we only need to draw when in between |
| final int left = scrollX - offset + width; |
| mMarginDrawable.setBounds(left, mTopPageBounds, left + mPageMargin, |
| mBottomPageBounds); |
| mMarginDrawable.draw(canvas); |
| } |
| } |
| } |
| |
| /** |
| * Start a fake drag of the pager. |
| * |
| * <p>A fake drag can be useful if you want to synchronize the motion of the ViewPager |
| * with the touch scrolling of another view, while still letting the ViewPager |
| * control the snapping motion and fling behavior. (e.g. parallax-scrolling tabs.) |
| * Call {@link #fakeDragBy(float)} to simulate the actual drag motion. Call |
| * {@link #endFakeDrag()} to complete the fake drag and fling as necessary. |
| * |
| * <p>During a fake drag the ViewPager will ignore all touch events. If a real drag |
| * is already in progress, this method will return false. |
| * |
| * @return true if the fake drag began successfully, false if it could not be started. |
| * |
| * @see #fakeDragBy(float) |
| * @see #endFakeDrag() |
| */ |
| public boolean beginFakeDrag() { |
| if (mIsBeingDragged) { |
| return false; |
| } |
| mFakeDragging = true; |
| setScrollState(SCROLL_STATE_DRAGGING); |
| mInitialMotionX = mLastMotionX = 0; |
| if (mVelocityTracker == null) { |
| mVelocityTracker = VelocityTracker.obtain(); |
| } else { |
| mVelocityTracker.clear(); |
| } |
| final long time = SystemClock.uptimeMillis(); |
| final MotionEvent ev = MotionEvent.obtain(time, time, MotionEvent.ACTION_DOWN, 0, 0, 0); |
| mVelocityTracker.addMovement(ev); |
| ev.recycle(); |
| mFakeDragBeginTime = time; |
| return true; |
| } |
| |
| /** |
| * End a fake drag of the pager. |
| * |
| * @see #beginFakeDrag() |
| * @see #fakeDragBy(float) |
| */ |
| public void endFakeDrag() { |
| if (!mFakeDragging) { |
| throw new IllegalStateException("No fake drag in progress. Call beginFakeDrag first."); |
| } |
| |
| final VelocityTracker velocityTracker = mVelocityTracker; |
| velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); |
| int initialVelocity = (int)VelocityTrackerCompat.getYVelocity( |
| velocityTracker, mActivePointerId); |
| mPopulatePending = true; |
| if ((Math.abs(initialVelocity) > mMinimumVelocity) |
| || Math.abs(mInitialMotionX-mLastMotionX) >= (getWidth()/3)) { |
| if (mLastMotionX > mInitialMotionX) { |
| setCurrentItemInternal(mCurItem-1, true, true); |
| } else { |
| setCurrentItemInternal(mCurItem+1, true, true); |
| } |
| } else { |
| setCurrentItemInternal(mCurItem, true, true); |
| } |
| endDrag(); |
| |
| mFakeDragging = false; |
| } |
| |
| /** |
| * Fake drag by an offset in pixels. You must have called {@link #beginFakeDrag()} first. |
| * |
| * @param xOffset Offset in pixels to drag by. |
| * @see #beginFakeDrag() |
| * @see #endFakeDrag() |
| */ |
| public void fakeDragBy(float xOffset) { |
| if (!mFakeDragging) { |
| throw new IllegalStateException("No fake drag in progress. Call beginFakeDrag first."); |
| } |
| |
| mLastMotionX += xOffset; |
| float scrollX = getScrollX() - xOffset; |
| final int width = getWidth(); |
| final int widthWithMargin = width + mPageMargin; |
| |
| final float leftBound = Math.max(0, (mCurItem - 1) * widthWithMargin); |
| final float rightBound = |
| Math.min(mCurItem + 1, mAdapter.getCount() - 1) * widthWithMargin; |
| if (scrollX < leftBound) { |
| scrollX = leftBound; |
| } else if (scrollX > rightBound) { |
| scrollX = rightBound; |
| } |
| // Don't lose the rounded component |
| mLastMotionX += scrollX - (int) scrollX; |
| scrollTo((int) scrollX, getScrollY()); |
| pageScrolled((int) scrollX); |
| |
| // Synthesize an event for the VelocityTracker. |
| final long time = SystemClock.uptimeMillis(); |
| final MotionEvent ev = MotionEvent.obtain(mFakeDragBeginTime, time, MotionEvent.ACTION_MOVE, |
| mLastMotionX, 0, 0); |
| mVelocityTracker.addMovement(ev); |
| ev.recycle(); |
| } |
| |
| /** |
| * Returns true if a fake drag is in progress. |
| * |
| * @return true if currently in a fake drag, false otherwise. |
| * |
| * @see #beginFakeDrag() |
| * @see #fakeDragBy(float) |
| * @see #endFakeDrag() |
| */ |
| public boolean isFakeDragging() { |
| return mFakeDragging; |
| } |
| |
| private void onSecondaryPointerUp(MotionEvent ev) { |
| final int pointerIndex = MotionEventCompat.getActionIndex(ev); |
| final int pointerId = MotionEventCompat.getPointerId(ev, pointerIndex); |
| if (pointerId == mActivePointerId) { |
| // This was our active pointer going up. Choose a new |
| // active pointer and adjust accordingly. |
| final int newPointerIndex = pointerIndex == 0 ? 1 : 0; |
| mLastMotionX = MotionEventCompat.getX(ev, newPointerIndex); |
| mActivePointerId = MotionEventCompat.getPointerId(ev, newPointerIndex); |
| if (mVelocityTracker != null) { |
| mVelocityTracker.clear(); |
| } |
| } |
| } |
| |
| private void endDrag() { |
| mIsBeingDragged = false; |
| mIsUnableToDrag = false; |
| |
| if (mVelocityTracker != null) { |
| mVelocityTracker.recycle(); |
| mVelocityTracker = null; |
| } |
| } |
| |
| private void setScrollingCacheEnabled(boolean enabled) { |
| if (mScrollingCacheEnabled != enabled) { |
| mScrollingCacheEnabled = enabled; |
| if (USE_CACHE) { |
| final int size = getChildCount(); |
| for (int i = 0; i < size; ++i) { |
| final View child = getChildAt(i); |
| if (child.getVisibility() != GONE) { |
| child.setDrawingCacheEnabled(enabled); |
| } |
| } |
| } |
| } |
| } |
| |
| /** |
| * Tests scrollability within child views of v given a delta of dx. |
| * |
| * @param v View to test for horizontal scrollability |
| * @param checkV Whether the view v passed should itself be checked for scrollability (true), |
| * or just its children (false). |
| * @param dx Delta scrolled in pixels |
| * @param x X coordinate of the active touch point |
| * @param y Y coordinate of the active touch point |
| * @return true if child views of v can be scrolled by delta of dx. |
| */ |
| protected boolean canScroll(View v, boolean checkV, int dx, int x, int y) { |
| if (v instanceof ViewGroup) { |
| final ViewGroup group = (ViewGroup) v; |
| final int scrollX = v.getScrollX(); |
| final int scrollY = v.getScrollY(); |
| final int count = group.getChildCount(); |
| // Count backwards - let topmost views consume scroll distance first. |
| for (int i = count - 1; i >= 0; i--) { |
| // TODO: Add versioned support here for transformed views. |
| // This will not work for transformed views in Honeycomb+ |
| final View child = group.getChildAt(i); |
| if (x + scrollX >= child.getLeft() && x + scrollX < child.getRight() && |
| y + scrollY >= child.getTop() && y + scrollY < child.getBottom() && |
| canScroll(child, true, dx, x + scrollX - child.getLeft(), |
| y + scrollY - child.getTop())) { |
| return true; |
| } |
| } |
| } |
| |
| return checkV && ViewCompat.canScrollHorizontally(v, -dx); |
| } |
| |
| @Override |
| public boolean dispatchKeyEvent(KeyEvent event) { |
| // Let the focused view and/or our descendants get the key first |
| return super.dispatchKeyEvent(event) || executeKeyEvent(event); |
| } |
| |
| /** |
| * You can call this function yourself to have the scroll view perform |
| * scrolling from a key event, just as if the event had been dispatched to |
| * it by the view hierarchy. |
| * |
| * @param event The key event to execute. |
| * @return Return true if the event was handled, else false. |
| */ |
| public boolean executeKeyEvent(KeyEvent event) { |
| boolean handled = false; |
| if (event.getAction() == KeyEvent.ACTION_DOWN) { |
| switch (event.getKeyCode()) { |
| case KeyEvent.KEYCODE_DPAD_LEFT: |
| handled = arrowScroll(FOCUS_LEFT); |
| break; |
| case KeyEvent.KEYCODE_DPAD_RIGHT: |
| handled = arrowScroll(FOCUS_RIGHT); |
| break; |
| case KeyEvent.KEYCODE_TAB: |
| if (KeyEventCompat.hasNoModifiers(event)) { |
| handled = arrowScroll(FOCUS_FORWARD); |
| } else if (KeyEventCompat.hasModifiers(event, KeyEvent.META_SHIFT_ON)) { |
| handled = arrowScroll(FOCUS_BACKWARD); |
| } |
| break; |
| } |
| } |
| return handled; |
| } |
| |
| public boolean arrowScroll(int direction) { |
| View currentFocused = findFocus(); |
| if (currentFocused == this) currentFocused = null; |
| |
| boolean handled = false; |
| |
| View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused, |
| direction); |
| if (nextFocused != null && nextFocused != currentFocused) { |
| if (direction == View.FOCUS_LEFT) { |
| // If there is nothing to the left, or this is causing us to |
| // jump to the right, then what we really want to do is page left. |
| if (currentFocused != null && nextFocused.getLeft() >= currentFocused.getLeft()) { |
| handled = pageLeft(); |
| } else { |
| handled = nextFocused.requestFocus(); |
| } |
| } else if (direction == View.FOCUS_RIGHT) { |
| // If there is nothing to the right, or this is causing us to |
| // jump to the left, then what we really want to do is page right. |
| if (currentFocused != null && nextFocused.getLeft() <= currentFocused.getLeft()) { |
| handled = pageRight(); |
| } else { |
| handled = nextFocused.requestFocus(); |
| } |
| } |
| } else if (direction == FOCUS_LEFT || direction == FOCUS_BACKWARD) { |
| // Trying to move left and nothing there; try to page. |
| handled = pageLeft(); |
| } else if (direction == FOCUS_RIGHT || direction == FOCUS_FORWARD) { |
| // Trying to move right and nothing there; try to page. |
| handled = pageRight(); |
| } |
| if (handled) { |
| playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); |
| } |
| return handled; |
| } |
| |
| boolean pageLeft() { |
| if (mCurItem > 0) { |
| setCurrentItem(mCurItem-1, true); |
| return true; |
| } |
| return false; |
| } |
| |
| boolean pageRight() { |
| if (mAdapter != null && mCurItem < (mAdapter.getCount()-1)) { |
| setCurrentItem(mCurItem+1, true); |
| return true; |
| } |
| return false; |
| } |
| |
| /** |
| * We only want the current page that is being shown to be focusable. |
| */ |
| @Override |
| public void addFocusables(ArrayList<View> views, int direction, int focusableMode) { |
| final int focusableCount = views.size(); |
| |
| final int descendantFocusability = getDescendantFocusability(); |
| |
| if (descendantFocusability != FOCUS_BLOCK_DESCENDANTS) { |
| for (int i = 0; i < getChildCount(); i++) { |
| final View child = getChildAt(i); |
| if (child.getVisibility() == VISIBLE) { |
| ItemInfo ii = infoForChild(child); |
| if (ii != null && ii.position == mCurItem) { |
| child.addFocusables(views, direction, focusableMode); |
| } |
| } |
| } |
| } |
| |
| // we add ourselves (if focusable) in all cases except for when we are |
| // FOCUS_AFTER_DESCENDANTS and there are some descendants focusable. this is |
| // to avoid the focus search finding layouts when a more precise search |
| // among the focusable children would be more interesting. |
| if ( |
| descendantFocusability != FOCUS_AFTER_DESCENDANTS || |
| // No focusable descendants |
| (focusableCount == views.size())) { |
| // Note that we can't call the superclass here, because it will |
| // add all views in. So we need to do the same thing View does. |
| if (!isFocusable()) { |
| return; |
| } |
| if ((focusableMode & FOCUSABLES_TOUCH_MODE) == FOCUSABLES_TOUCH_MODE && |
| isInTouchMode() && !isFocusableInTouchMode()) { |
| return; |
| } |
| if (views != null) { |
| views.add(this); |
| } |
| } |
| } |
| |
| /** |
| * We only want the current page that is being shown to be touchable. |
| */ |
| @Override |
| public void addTouchables(ArrayList<View> views) { |
| // Note that we don't call super.addTouchables(), which means that |
| // we don't call View.addTouchables(). This is okay because a ViewPager |
| // is itself not touchable. |
| for (int i = 0; i < getChildCount(); i++) { |
| final View child = getChildAt(i); |
| if (child.getVisibility() == VISIBLE) { |
| ItemInfo ii = infoForChild(child); |
| if (ii != null && ii.position == mCurItem) { |
| child.addTouchables(views); |
| } |
| } |
| } |
| } |
| |
| /** |
| * We only want the current page that is being shown to be focusable. |
| */ |
| @Override |
| protected boolean onRequestFocusInDescendants(int direction, |
| Rect previouslyFocusedRect) { |
| int index; |
| int increment; |
| int end; |
| int count = getChildCount(); |
| if ((direction & FOCUS_FORWARD) != 0) { |
| index = 0; |
| increment = 1; |
| end = count; |
| } else { |
| index = count - 1; |
| increment = -1; |
| end = -1; |
| } |
| for (int i = index; i != end; i += increment) { |
| View child = getChildAt(i); |
| if (child.getVisibility() == VISIBLE) { |
| ItemInfo ii = infoForChild(child); |
| if (ii != null && ii.position == mCurItem) { |
| if (child.requestFocus(direction, previouslyFocusedRect)) { |
| return true; |
| } |
| } |
| } |
| } |
| return false; |
| } |
| |
| @Override |
| public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) { |
| // ViewPagers should only report accessibility info for the current page, |
| // otherwise things get very confusing. |
| |
| // TODO: Should this note something about the paging container? |
| |
| final int childCount = getChildCount(); |
| for (int i = 0; i < childCount; i++) { |
| final View child = getChildAt(i); |
| if (child.getVisibility() == VISIBLE) { |
| final ItemInfo ii = infoForChild(child); |
| if (ii != null && ii.position == mCurItem && |
| child.dispatchPopulateAccessibilityEvent(event)) { |
| return true; |
| } |
| } |
| } |
| |
| return false; |
| } |
| |
| @Override |
| protected ViewGroup.LayoutParams generateDefaultLayoutParams() { |
| return new LayoutParams(); |
| } |
| |
| @Override |
| protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) { |
| return generateDefaultLayoutParams(); |
| } |
| |
| @Override |
| protected boolean checkLayoutParams(ViewGroup.LayoutParams p) { |
| return p instanceof LayoutParams && super.checkLayoutParams(p); |
| } |
| |
| @Override |
| public ViewGroup.LayoutParams generateLayoutParams(AttributeSet attrs) { |
| return new LayoutParams(getContext(), attrs); |
| } |
| |
| private class PagerObserver extends DataSetObserver { |
| @Override |
| public void onChanged() { |
| dataSetChanged(); |
| } |
| @Override |
| public void onInvalidated() { |
| dataSetChanged(); |
| } |
| } |
| |
| public static class LayoutParams extends ViewGroup.LayoutParams { |
| /** |
| * true if this view is a decoration on the pager itself and not |
| * a view supplied by the adapter. |
| */ |
| public boolean isDecor; |
| |
| public int gravity; |
| |
| public LayoutParams() { |
| super(FILL_PARENT, FILL_PARENT); |
| } |
| |
| public LayoutParams(Context context, AttributeSet attrs) { |
| super(context, attrs); |
| |
| final TypedArray a = context.obtainStyledAttributes(attrs, LAYOUT_ATTRS); |
| gravity = a.getInteger(0, Gravity.NO_GRAVITY); |
| a.recycle(); |
| } |
| } |
| } |