| /* |
| * Copyright (C) 2010 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 com.android.launcher2; |
| |
| import android.animation.Animator; |
| import android.animation.AnimatorListenerAdapter; |
| import android.animation.ObjectAnimator; |
| import android.animation.ValueAnimator; |
| import android.content.Context; |
| import android.content.res.TypedArray; |
| import android.graphics.Canvas; |
| import android.graphics.Rect; |
| import android.os.Bundle; |
| import android.os.Parcel; |
| import android.os.Parcelable; |
| import android.util.AttributeSet; |
| import android.util.Log; |
| import android.view.InputDevice; |
| import android.view.KeyEvent; |
| import android.view.MotionEvent; |
| 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.accessibility.AccessibilityManager; |
| import android.view.accessibility.AccessibilityNodeInfo; |
| import android.view.animation.Interpolator; |
| import android.widget.Scroller; |
| |
| import com.android.launcher.R; |
| |
| import java.util.ArrayList; |
| |
| /** |
| * An abstraction of the original Workspace which supports browsing through a |
| * sequential list of "pages" |
| */ |
| public abstract class PagedView extends ViewGroup implements ViewGroup.OnHierarchyChangeListener { |
| private static final String TAG = "PagedView"; |
| private static final boolean DEBUG = false; |
| protected static final int INVALID_PAGE = -1; |
| |
| // the min drag distance for a fling to register, to prevent random page shifts |
| private static final int MIN_LENGTH_FOR_FLING = 25; |
| |
| protected static final int PAGE_SNAP_ANIMATION_DURATION = 550; |
| protected static final int SLOW_PAGE_SNAP_ANIMATION_DURATION = 950; |
| protected static final float NANOTIME_DIV = 1000000000.0f; |
| |
| private static final float OVERSCROLL_ACCELERATE_FACTOR = 2; |
| private static final float OVERSCROLL_DAMP_FACTOR = 0.14f; |
| |
| private static final float RETURN_TO_ORIGINAL_PAGE_THRESHOLD = 0.33f; |
| // The page is moved more than halfway, automatically move to the next page on touch up. |
| private static final float SIGNIFICANT_MOVE_THRESHOLD = 0.4f; |
| |
| // The following constants need to be scaled based on density. The scaled versions will be |
| // assigned to the corresponding member variables below. |
| private static final int FLING_THRESHOLD_VELOCITY = 500; |
| private static final int MIN_SNAP_VELOCITY = 1500; |
| private static final int MIN_FLING_VELOCITY = 250; |
| |
| static final int AUTOMATIC_PAGE_SPACING = -1; |
| |
| protected int mFlingThresholdVelocity; |
| protected int mMinFlingVelocity; |
| protected int mMinSnapVelocity; |
| |
| protected float mDensity; |
| protected float mSmoothingTime; |
| protected float mTouchX; |
| |
| protected boolean mFirstLayout = true; |
| |
| protected int mCurrentPage; |
| protected int mNextPage = INVALID_PAGE; |
| protected int mMaxScrollX; |
| protected Scroller mScroller; |
| private VelocityTracker mVelocityTracker; |
| |
| private float mDownMotionX; |
| protected float mLastMotionX; |
| protected float mLastMotionXRemainder; |
| protected float mLastMotionY; |
| protected float mTotalMotionX; |
| private int mLastScreenCenter = -1; |
| private int[] mChildOffsets; |
| private int[] mChildRelativeOffsets; |
| private int[] mChildOffsetsWithLayoutScale; |
| |
| protected final static int TOUCH_STATE_REST = 0; |
| protected final static int TOUCH_STATE_SCROLLING = 1; |
| protected final static int TOUCH_STATE_PREV_PAGE = 2; |
| protected final static int TOUCH_STATE_NEXT_PAGE = 3; |
| protected final static float ALPHA_QUANTIZE_LEVEL = 0.0001f; |
| |
| protected int mTouchState = TOUCH_STATE_REST; |
| protected boolean mForceScreenScrolled = false; |
| |
| protected OnLongClickListener mLongClickListener; |
| |
| protected boolean mAllowLongPress = true; |
| |
| protected int mTouchSlop; |
| private int mPagingTouchSlop; |
| private int mMaximumVelocity; |
| private int mMinimumWidth; |
| protected int mPageSpacing; |
| protected int mPageLayoutPaddingTop; |
| protected int mPageLayoutPaddingBottom; |
| protected int mPageLayoutPaddingLeft; |
| protected int mPageLayoutPaddingRight; |
| protected int mPageLayoutWidthGap; |
| protected int mPageLayoutHeightGap; |
| protected int mCellCountX = 0; |
| protected int mCellCountY = 0; |
| protected boolean mCenterPagesVertically; |
| protected boolean mAllowOverScroll = true; |
| protected int mUnboundedScrollX; |
| protected int[] mTempVisiblePagesRange = new int[2]; |
| protected boolean mForceDrawAllChildrenNextFrame; |
| |
| // mOverScrollX is equal to getScrollX() when we're within the normal scroll range. Otherwise |
| // it is equal to the scaled overscroll position. We use a separate value so as to prevent |
| // the screens from continuing to translate beyond the normal bounds. |
| protected int mOverScrollX; |
| |
| // parameter that adjusts the layout to be optimized for pages with that scale factor |
| protected float mLayoutScale = 1.0f; |
| |
| protected static final int INVALID_POINTER = -1; |
| |
| protected int mActivePointerId = INVALID_POINTER; |
| |
| private PageSwitchListener mPageSwitchListener; |
| |
| protected ArrayList<Boolean> mDirtyPageContent; |
| |
| // If true, syncPages and syncPageItems will be called to refresh pages |
| protected boolean mContentIsRefreshable = true; |
| |
| // If true, modify alpha of neighboring pages as user scrolls left/right |
| protected boolean mFadeInAdjacentScreens = true; |
| |
| // It true, use a different slop parameter (pagingTouchSlop = 2 * touchSlop) for deciding |
| // to switch to a new page |
| protected boolean mUsePagingTouchSlop = true; |
| |
| // If true, the subclass should directly update scrollX itself in its computeScroll method |
| // (SmoothPagedView does this) |
| protected boolean mDeferScrollUpdate = false; |
| |
| protected boolean mIsPageMoving = false; |
| |
| // All syncs and layout passes are deferred until data is ready. |
| protected boolean mIsDataReady = false; |
| |
| // Scrolling indicator |
| private ValueAnimator mScrollIndicatorAnimator; |
| private View mScrollIndicator; |
| private int mScrollIndicatorPaddingLeft; |
| private int mScrollIndicatorPaddingRight; |
| private boolean mHasScrollIndicator = true; |
| private boolean mShouldShowScrollIndicator = false; |
| private boolean mShouldShowScrollIndicatorImmediately = false; |
| protected static final int sScrollIndicatorFadeInDuration = 150; |
| protected static final int sScrollIndicatorFadeOutDuration = 650; |
| protected static final int sScrollIndicatorFlashDuration = 650; |
| |
| // If set, will defer loading associated pages until the scrolling settles |
| private boolean mDeferLoadAssociatedPagesUntilScrollCompletes; |
| |
| public interface PageSwitchListener { |
| void onPageSwitch(View newPage, int newPageIndex); |
| } |
| |
| public PagedView(Context context) { |
| this(context, null); |
| } |
| |
| public PagedView(Context context, AttributeSet attrs) { |
| this(context, attrs, 0); |
| } |
| |
| public PagedView(Context context, AttributeSet attrs, int defStyle) { |
| super(context, attrs, defStyle); |
| |
| TypedArray a = context.obtainStyledAttributes(attrs, |
| R.styleable.PagedView, defStyle, 0); |
| setPageSpacing(a.getDimensionPixelSize(R.styleable.PagedView_pageSpacing, 0)); |
| mPageLayoutPaddingTop = a.getDimensionPixelSize( |
| R.styleable.PagedView_pageLayoutPaddingTop, 0); |
| mPageLayoutPaddingBottom = a.getDimensionPixelSize( |
| R.styleable.PagedView_pageLayoutPaddingBottom, 0); |
| mPageLayoutPaddingLeft = a.getDimensionPixelSize( |
| R.styleable.PagedView_pageLayoutPaddingLeft, 0); |
| mPageLayoutPaddingRight = a.getDimensionPixelSize( |
| R.styleable.PagedView_pageLayoutPaddingRight, 0); |
| mPageLayoutWidthGap = a.getDimensionPixelSize( |
| R.styleable.PagedView_pageLayoutWidthGap, 0); |
| mPageLayoutHeightGap = a.getDimensionPixelSize( |
| R.styleable.PagedView_pageLayoutHeightGap, 0); |
| mScrollIndicatorPaddingLeft = |
| a.getDimensionPixelSize(R.styleable.PagedView_scrollIndicatorPaddingLeft, 0); |
| mScrollIndicatorPaddingRight = |
| a.getDimensionPixelSize(R.styleable.PagedView_scrollIndicatorPaddingRight, 0); |
| a.recycle(); |
| |
| setHapticFeedbackEnabled(false); |
| init(); |
| } |
| |
| /** |
| * Initializes various states for this workspace. |
| */ |
| protected void init() { |
| mDirtyPageContent = new ArrayList<Boolean>(); |
| mDirtyPageContent.ensureCapacity(32); |
| mScroller = new Scroller(getContext(), new ScrollInterpolator()); |
| mCurrentPage = 0; |
| mCenterPagesVertically = true; |
| |
| final ViewConfiguration configuration = ViewConfiguration.get(getContext()); |
| mTouchSlop = configuration.getScaledTouchSlop(); |
| mPagingTouchSlop = configuration.getScaledPagingTouchSlop(); |
| mMaximumVelocity = configuration.getScaledMaximumFlingVelocity(); |
| mDensity = getResources().getDisplayMetrics().density; |
| |
| mFlingThresholdVelocity = (int) (FLING_THRESHOLD_VELOCITY * mDensity); |
| mMinFlingVelocity = (int) (MIN_FLING_VELOCITY * mDensity); |
| mMinSnapVelocity = (int) (MIN_SNAP_VELOCITY * mDensity); |
| setOnHierarchyChangeListener(this); |
| } |
| |
| public void setPageSwitchListener(PageSwitchListener pageSwitchListener) { |
| mPageSwitchListener = pageSwitchListener; |
| if (mPageSwitchListener != null) { |
| mPageSwitchListener.onPageSwitch(getPageAt(mCurrentPage), mCurrentPage); |
| } |
| } |
| |
| /** |
| * Called by subclasses to mark that data is ready, and that we can begin loading and laying |
| * out pages. |
| */ |
| protected void setDataIsReady() { |
| mIsDataReady = true; |
| } |
| protected boolean isDataReady() { |
| return mIsDataReady; |
| } |
| |
| /** |
| * Returns the index of the currently displayed page. |
| * |
| * @return The index of the currently displayed page. |
| */ |
| int getCurrentPage() { |
| return mCurrentPage; |
| } |
| int getNextPage() { |
| return (mNextPage != INVALID_PAGE) ? mNextPage : mCurrentPage; |
| } |
| |
| int getPageCount() { |
| return getChildCount(); |
| } |
| |
| View getPageAt(int index) { |
| return getChildAt(index); |
| } |
| |
| protected int indexToPage(int index) { |
| return index; |
| } |
| |
| /** |
| * Updates the scroll of the current page immediately to its final scroll position. We use this |
| * in CustomizePagedView to allow tabs to share the same PagedView while resetting the scroll of |
| * the previous tab page. |
| */ |
| protected void updateCurrentPageScroll() { |
| int offset = getChildOffset(mCurrentPage); |
| int relOffset = getRelativeChildOffset(mCurrentPage); |
| int newX = offset - relOffset; |
| scrollTo(newX, 0); |
| mScroller.setFinalX(newX); |
| mScroller.forceFinished(true); |
| } |
| |
| /** |
| * Sets the current page. |
| */ |
| void setCurrentPage(int currentPage) { |
| if (!mScroller.isFinished()) { |
| mScroller.abortAnimation(); |
| } |
| // don't introduce any checks like mCurrentPage == currentPage here-- if we change the |
| // the default |
| if (getChildCount() == 0) { |
| return; |
| } |
| |
| |
| mCurrentPage = Math.max(0, Math.min(currentPage, getPageCount() - 1)); |
| updateCurrentPageScroll(); |
| updateScrollingIndicator(); |
| notifyPageSwitchListener(); |
| invalidate(); |
| } |
| |
| protected void notifyPageSwitchListener() { |
| if (mPageSwitchListener != null) { |
| mPageSwitchListener.onPageSwitch(getPageAt(mCurrentPage), mCurrentPage); |
| } |
| } |
| |
| protected void pageBeginMoving() { |
| if (!mIsPageMoving) { |
| mIsPageMoving = true; |
| onPageBeginMoving(); |
| } |
| } |
| |
| protected void pageEndMoving() { |
| if (mIsPageMoving) { |
| mIsPageMoving = false; |
| onPageEndMoving(); |
| } |
| } |
| |
| protected boolean isPageMoving() { |
| return mIsPageMoving; |
| } |
| |
| // a method that subclasses can override to add behavior |
| protected void onPageBeginMoving() { |
| } |
| |
| // a method that subclasses can override to add behavior |
| protected void onPageEndMoving() { |
| } |
| |
| /** |
| * Registers the specified listener on each page contained in this workspace. |
| * |
| * @param l The listener used to respond to long clicks. |
| */ |
| @Override |
| public void setOnLongClickListener(OnLongClickListener l) { |
| mLongClickListener = l; |
| final int count = getPageCount(); |
| for (int i = 0; i < count; i++) { |
| getPageAt(i).setOnLongClickListener(l); |
| } |
| } |
| |
| @Override |
| public void scrollBy(int x, int y) { |
| scrollTo(mUnboundedScrollX + x, getScrollY() + y); |
| } |
| |
| @Override |
| public void scrollTo(int x, int y) { |
| mUnboundedScrollX = x; |
| |
| if (x < 0) { |
| super.scrollTo(0, y); |
| if (mAllowOverScroll) { |
| overScroll(x); |
| } |
| } else if (x > mMaxScrollX) { |
| super.scrollTo(mMaxScrollX, y); |
| if (mAllowOverScroll) { |
| overScroll(x - mMaxScrollX); |
| } |
| } else { |
| mOverScrollX = x; |
| super.scrollTo(x, y); |
| } |
| |
| mTouchX = x; |
| mSmoothingTime = System.nanoTime() / NANOTIME_DIV; |
| } |
| |
| // we moved this functionality to a helper function so SmoothPagedView can reuse it |
| protected boolean computeScrollHelper() { |
| if (mScroller.computeScrollOffset()) { |
| // Don't bother scrolling if the page does not need to be moved |
| if (getScrollX() != mScroller.getCurrX() |
| || getScrollY() != mScroller.getCurrY() |
| || mOverScrollX != mScroller.getCurrX()) { |
| scrollTo(mScroller.getCurrX(), mScroller.getCurrY()); |
| } |
| invalidate(); |
| return true; |
| } else if (mNextPage != INVALID_PAGE) { |
| mCurrentPage = Math.max(0, Math.min(mNextPage, getPageCount() - 1)); |
| mNextPage = INVALID_PAGE; |
| notifyPageSwitchListener(); |
| |
| // Load the associated pages if necessary |
| if (mDeferLoadAssociatedPagesUntilScrollCompletes) { |
| loadAssociatedPages(mCurrentPage); |
| mDeferLoadAssociatedPagesUntilScrollCompletes = false; |
| } |
| |
| // We don't want to trigger a page end moving unless the page has settled |
| // and the user has stopped scrolling |
| if (mTouchState == TOUCH_STATE_REST) { |
| pageEndMoving(); |
| } |
| |
| // Notify the user when the page changes |
| AccessibilityManager accessibilityManager = (AccessibilityManager) |
| getContext().getSystemService(Context.ACCESSIBILITY_SERVICE); |
| if (accessibilityManager.isEnabled()) { |
| AccessibilityEvent ev = |
| AccessibilityEvent.obtain(AccessibilityEvent.TYPE_VIEW_SCROLLED); |
| ev.getText().add(getCurrentPageDescription()); |
| sendAccessibilityEventUnchecked(ev); |
| } |
| return true; |
| } |
| return false; |
| } |
| |
| @Override |
| public void computeScroll() { |
| computeScrollHelper(); |
| } |
| |
| @Override |
| protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { |
| if (!mIsDataReady) { |
| super.onMeasure(widthMeasureSpec, heightMeasureSpec); |
| return; |
| } |
| |
| final int widthMode = MeasureSpec.getMode(widthMeasureSpec); |
| final int widthSize = MeasureSpec.getSize(widthMeasureSpec); |
| final int heightMode = MeasureSpec.getMode(heightMeasureSpec); |
| int heightSize = MeasureSpec.getSize(heightMeasureSpec); |
| if (widthMode != MeasureSpec.EXACTLY) { |
| throw new IllegalStateException("Workspace can only be used in EXACTLY mode."); |
| } |
| |
| // Return early if we aren't given a proper dimension |
| if (widthSize <= 0 || heightSize <= 0) { |
| super.onMeasure(widthMeasureSpec, heightMeasureSpec); |
| return; |
| } |
| |
| /* Allow the height to be set as WRAP_CONTENT. This allows the particular case |
| * of the All apps view on XLarge displays to not take up more space then it needs. Width |
| * is still not allowed to be set as WRAP_CONTENT since many parts of the code expect |
| * each page to have the same width. |
| */ |
| int maxChildHeight = 0; |
| |
| final int verticalPadding = getPaddingTop() + getPaddingBottom(); |
| final int horizontalPadding = getPaddingLeft() + getPaddingRight(); |
| |
| |
| // The children are given the same width and height as the workspace |
| // unless they were set to WRAP_CONTENT |
| if (DEBUG) Log.d(TAG, "PagedView.onMeasure(): " + widthSize + ", " + heightSize); |
| final int childCount = getChildCount(); |
| for (int i = 0; i < childCount; i++) { |
| // disallowing padding in paged view (just pass 0) |
| final View child = getPageAt(i); |
| final LayoutParams lp = (LayoutParams) child.getLayoutParams(); |
| |
| int childWidthMode; |
| if (lp.width == LayoutParams.WRAP_CONTENT) { |
| childWidthMode = MeasureSpec.AT_MOST; |
| } else { |
| childWidthMode = MeasureSpec.EXACTLY; |
| } |
| |
| int childHeightMode; |
| if (lp.height == LayoutParams.WRAP_CONTENT) { |
| childHeightMode = MeasureSpec.AT_MOST; |
| } else { |
| childHeightMode = MeasureSpec.EXACTLY; |
| } |
| |
| final int childWidthMeasureSpec = |
| MeasureSpec.makeMeasureSpec(widthSize - horizontalPadding, childWidthMode); |
| final int childHeightMeasureSpec = |
| MeasureSpec.makeMeasureSpec(heightSize - verticalPadding, childHeightMode); |
| |
| child.measure(childWidthMeasureSpec, childHeightMeasureSpec); |
| maxChildHeight = Math.max(maxChildHeight, child.getMeasuredHeight()); |
| if (DEBUG) Log.d(TAG, "\tmeasure-child" + i + ": " + child.getMeasuredWidth() + ", " |
| + child.getMeasuredHeight()); |
| } |
| |
| if (heightMode == MeasureSpec.AT_MOST) { |
| heightSize = maxChildHeight + verticalPadding; |
| } |
| |
| setMeasuredDimension(widthSize, heightSize); |
| |
| // We can't call getChildOffset/getRelativeChildOffset until we set the measured dimensions. |
| // We also wait until we set the measured dimensions before flushing the cache as well, to |
| // ensure that the cache is filled with good values. |
| invalidateCachedOffsets(); |
| |
| if (childCount > 0) { |
| if (DEBUG) Log.d(TAG, "getRelativeChildOffset(): " + getMeasuredWidth() + ", " |
| + getChildWidth(0)); |
| |
| // Calculate the variable page spacing if necessary |
| if (mPageSpacing == AUTOMATIC_PAGE_SPACING) { |
| // The gap between pages in the PagedView should be equal to the gap from the page |
| // to the edge of the screen (so it is not visible in the current screen). To |
| // account for unequal padding on each side of the paged view, we take the maximum |
| // of the left/right gap and use that as the gap between each page. |
| int offset = getRelativeChildOffset(0); |
| int spacing = Math.max(offset, widthSize - offset - |
| getChildAt(0).getMeasuredWidth()); |
| setPageSpacing(spacing); |
| } |
| } |
| |
| updateScrollingIndicatorPosition(); |
| |
| if (childCount > 0) { |
| mMaxScrollX = getChildOffset(childCount - 1) - getRelativeChildOffset(childCount - 1); |
| } else { |
| mMaxScrollX = 0; |
| } |
| } |
| |
| protected void scrollToNewPageWithoutMovingPages(int newCurrentPage) { |
| int newX = getChildOffset(newCurrentPage) - getRelativeChildOffset(newCurrentPage); |
| int delta = newX - getScrollX(); |
| |
| final int pageCount = getChildCount(); |
| for (int i = 0; i < pageCount; i++) { |
| View page = (View) getPageAt(i); |
| page.setX(page.getX() + delta); |
| } |
| setCurrentPage(newCurrentPage); |
| } |
| |
| // A layout scale of 1.0f assumes that the pages, in their unshrunken state, have a |
| // scale of 1.0f. A layout scale of 0.8f assumes the pages have a scale of 0.8f, and |
| // tightens the layout accordingly |
| public void setLayoutScale(float childrenScale) { |
| mLayoutScale = childrenScale; |
| invalidateCachedOffsets(); |
| |
| // Now we need to do a re-layout, but preserving absolute X and Y coordinates |
| int childCount = getChildCount(); |
| float childrenX[] = new float[childCount]; |
| float childrenY[] = new float[childCount]; |
| for (int i = 0; i < childCount; i++) { |
| final View child = getPageAt(i); |
| childrenX[i] = child.getX(); |
| childrenY[i] = child.getY(); |
| } |
| // Trigger a full re-layout (never just call onLayout directly!) |
| int widthSpec = MeasureSpec.makeMeasureSpec(getMeasuredWidth(), MeasureSpec.EXACTLY); |
| int heightSpec = MeasureSpec.makeMeasureSpec(getMeasuredHeight(), MeasureSpec.EXACTLY); |
| requestLayout(); |
| measure(widthSpec, heightSpec); |
| layout(getLeft(), getTop(), getRight(), getBottom()); |
| for (int i = 0; i < childCount; i++) { |
| final View child = getPageAt(i); |
| child.setX(childrenX[i]); |
| child.setY(childrenY[i]); |
| } |
| |
| // Also, the page offset has changed (since the pages are now smaller); |
| // update the page offset, but again preserving absolute X and Y coordinates |
| scrollToNewPageWithoutMovingPages(mCurrentPage); |
| } |
| |
| public void setPageSpacing(int pageSpacing) { |
| mPageSpacing = pageSpacing; |
| invalidateCachedOffsets(); |
| } |
| |
| @Override |
| protected void onLayout(boolean changed, int left, int top, int right, int bottom) { |
| if (!mIsDataReady) { |
| return; |
| } |
| |
| if (DEBUG) Log.d(TAG, "PagedView.onLayout()"); |
| final int verticalPadding = getPaddingTop() + getPaddingBottom(); |
| final int childCount = getChildCount(); |
| int childLeft = getRelativeChildOffset(0); |
| |
| for (int i = 0; i < childCount; i++) { |
| final View child = getPageAt(i); |
| if (child.getVisibility() != View.GONE) { |
| final int childWidth = getScaledMeasuredWidth(child); |
| final int childHeight = child.getMeasuredHeight(); |
| int childTop = getPaddingTop(); |
| if (mCenterPagesVertically) { |
| childTop += ((getMeasuredHeight() - verticalPadding) - childHeight) / 2; |
| } |
| |
| if (DEBUG) Log.d(TAG, "\tlayout-child" + i + ": " + childLeft + ", " + childTop); |
| child.layout(childLeft, childTop, |
| childLeft + child.getMeasuredWidth(), childTop + childHeight); |
| childLeft += childWidth + mPageSpacing; |
| } |
| } |
| |
| if (mFirstLayout && mCurrentPage >= 0 && mCurrentPage < getChildCount()) { |
| setHorizontalScrollBarEnabled(false); |
| updateCurrentPageScroll(); |
| setHorizontalScrollBarEnabled(true); |
| mFirstLayout = false; |
| } |
| } |
| |
| protected void screenScrolled(int screenCenter) { |
| if (isScrollingIndicatorEnabled()) { |
| updateScrollingIndicator(); |
| } |
| boolean isInOverscroll = mOverScrollX < 0 || mOverScrollX > mMaxScrollX; |
| |
| if (mFadeInAdjacentScreens && !isInOverscroll) { |
| for (int i = 0; i < getChildCount(); i++) { |
| View child = getChildAt(i); |
| if (child != null) { |
| float scrollProgress = getScrollProgress(screenCenter, child, i); |
| float alpha = 1 - Math.abs(scrollProgress); |
| child.setAlpha(alpha); |
| } |
| } |
| invalidate(); |
| } |
| } |
| |
| @Override |
| public void onChildViewAdded(View parent, View child) { |
| // This ensures that when children are added, they get the correct transforms / alphas |
| // in accordance with any scroll effects. |
| mForceScreenScrolled = true; |
| invalidate(); |
| invalidateCachedOffsets(); |
| } |
| |
| @Override |
| public void onChildViewRemoved(View parent, View child) { |
| } |
| |
| protected void invalidateCachedOffsets() { |
| int count = getChildCount(); |
| if (count == 0) { |
| mChildOffsets = null; |
| mChildRelativeOffsets = null; |
| mChildOffsetsWithLayoutScale = null; |
| return; |
| } |
| |
| mChildOffsets = new int[count]; |
| mChildRelativeOffsets = new int[count]; |
| mChildOffsetsWithLayoutScale = new int[count]; |
| for (int i = 0; i < count; i++) { |
| mChildOffsets[i] = -1; |
| mChildRelativeOffsets[i] = -1; |
| mChildOffsetsWithLayoutScale[i] = -1; |
| } |
| } |
| |
| protected int getChildOffset(int index) { |
| int[] childOffsets = Float.compare(mLayoutScale, 1f) == 0 ? |
| mChildOffsets : mChildOffsetsWithLayoutScale; |
| |
| if (childOffsets != null && childOffsets[index] != -1) { |
| return childOffsets[index]; |
| } else { |
| if (getChildCount() == 0) |
| return 0; |
| |
| int offset = getRelativeChildOffset(0); |
| for (int i = 0; i < index; ++i) { |
| offset += getScaledMeasuredWidth(getPageAt(i)) + mPageSpacing; |
| } |
| if (childOffsets != null) { |
| childOffsets[index] = offset; |
| } |
| return offset; |
| } |
| } |
| |
| protected int getRelativeChildOffset(int index) { |
| if (mChildRelativeOffsets != null && mChildRelativeOffsets[index] != -1) { |
| return mChildRelativeOffsets[index]; |
| } else { |
| final int padding = getPaddingLeft() + getPaddingRight(); |
| final int offset = getPaddingLeft() + |
| (getMeasuredWidth() - padding - getChildWidth(index)) / 2; |
| if (mChildRelativeOffsets != null) { |
| mChildRelativeOffsets[index] = offset; |
| } |
| return offset; |
| } |
| } |
| |
| protected int getScaledMeasuredWidth(View child) { |
| // This functions are called enough times that it actually makes a difference in the |
| // profiler -- so just inline the max() here |
| final int measuredWidth = child.getMeasuredWidth(); |
| final int minWidth = mMinimumWidth; |
| final int maxWidth = (minWidth > measuredWidth) ? minWidth : measuredWidth; |
| return (int) (maxWidth * mLayoutScale + 0.5f); |
| } |
| |
| protected void getVisiblePages(int[] range) { |
| final int pageCount = getChildCount(); |
| |
| if (pageCount > 0) { |
| final int screenWidth = getMeasuredWidth(); |
| int leftScreen = 0; |
| int rightScreen = 0; |
| View currPage = getPageAt(leftScreen); |
| while (leftScreen < pageCount - 1 && |
| currPage.getX() + currPage.getWidth() - |
| currPage.getPaddingRight() < getScrollX()) { |
| leftScreen++; |
| currPage = getPageAt(leftScreen); |
| } |
| rightScreen = leftScreen; |
| currPage = getPageAt(rightScreen + 1); |
| while (rightScreen < pageCount - 1 && |
| currPage.getX() - currPage.getPaddingLeft() < getScrollX() + screenWidth) { |
| rightScreen++; |
| currPage = getPageAt(rightScreen + 1); |
| } |
| range[0] = leftScreen; |
| range[1] = rightScreen; |
| } else { |
| range[0] = -1; |
| range[1] = -1; |
| } |
| } |
| |
| protected boolean shouldDrawChild(View child) { |
| return child.getAlpha() > 0; |
| } |
| |
| @Override |
| protected void dispatchDraw(Canvas canvas) { |
| int halfScreenSize = getMeasuredWidth() / 2; |
| // mOverScrollX is equal to getScrollX() when we're within the normal scroll range. |
| // Otherwise it is equal to the scaled overscroll position. |
| int screenCenter = mOverScrollX + halfScreenSize; |
| |
| if (screenCenter != mLastScreenCenter || mForceScreenScrolled) { |
| // set mForceScreenScrolled before calling screenScrolled so that screenScrolled can |
| // set it for the next frame |
| mForceScreenScrolled = false; |
| screenScrolled(screenCenter); |
| mLastScreenCenter = screenCenter; |
| } |
| |
| // Find out which screens are visible; as an optimization we only call draw on them |
| final int pageCount = getChildCount(); |
| if (pageCount > 0) { |
| getVisiblePages(mTempVisiblePagesRange); |
| final int leftScreen = mTempVisiblePagesRange[0]; |
| final int rightScreen = mTempVisiblePagesRange[1]; |
| if (leftScreen != -1 && rightScreen != -1) { |
| final long drawingTime = getDrawingTime(); |
| // Clip to the bounds |
| canvas.save(); |
| canvas.clipRect(getScrollX(), getScrollY(), getScrollX() + getRight() - getLeft(), |
| getScrollY() + getBottom() - getTop()); |
| |
| // On certain graphics drivers, if you draw to a off-screen buffer that's not |
| // used, it can lead to poor performance. We were running into this when |
| // setChildrenLayersEnabled was called on a CellLayout; that triggered a re-draw |
| // of that CellLayout's hardware layer, even if that CellLayout wasn't visible. |
| // As a fix, below we set pages that aren't going to be rendered are to be |
| // View.INVISIBLE, preventing re-drawing of their hardware layer |
| for (int i = getChildCount() - 1; i >= 0; i--) { |
| final View v = getPageAt(i); |
| if (mForceDrawAllChildrenNextFrame || |
| (leftScreen <= i && i <= rightScreen && shouldDrawChild(v))) { |
| v.setVisibility(VISIBLE); |
| drawChild(canvas, v, drawingTime); |
| } else { |
| v.setVisibility(INVISIBLE); |
| } |
| } |
| mForceDrawAllChildrenNextFrame = false; |
| canvas.restore(); |
| } |
| } |
| } |
| |
| @Override |
| public boolean requestChildRectangleOnScreen(View child, Rect rectangle, boolean immediate) { |
| int page = indexToPage(indexOfChild(child)); |
| if (page != mCurrentPage || !mScroller.isFinished()) { |
| snapToPage(page); |
| return true; |
| } |
| return false; |
| } |
| |
| @Override |
| protected boolean onRequestFocusInDescendants(int direction, Rect previouslyFocusedRect) { |
| int focusablePage; |
| if (mNextPage != INVALID_PAGE) { |
| focusablePage = mNextPage; |
| } else { |
| focusablePage = mCurrentPage; |
| } |
| View v = getPageAt(focusablePage); |
| if (v != null) { |
| return v.requestFocus(direction, previouslyFocusedRect); |
| } |
| return false; |
| } |
| |
| @Override |
| public boolean dispatchUnhandledMove(View focused, int direction) { |
| if (direction == View.FOCUS_LEFT) { |
| if (getCurrentPage() > 0) { |
| snapToPage(getCurrentPage() - 1); |
| return true; |
| } |
| } else if (direction == View.FOCUS_RIGHT) { |
| if (getCurrentPage() < getPageCount() - 1) { |
| snapToPage(getCurrentPage() + 1); |
| return true; |
| } |
| } |
| return super.dispatchUnhandledMove(focused, direction); |
| } |
| |
| @Override |
| public void addFocusables(ArrayList<View> views, int direction, int focusableMode) { |
| if (mCurrentPage >= 0 && mCurrentPage < getPageCount()) { |
| getPageAt(mCurrentPage).addFocusables(views, direction, focusableMode); |
| } |
| if (direction == View.FOCUS_LEFT) { |
| if (mCurrentPage > 0) { |
| getPageAt(mCurrentPage - 1).addFocusables(views, direction, focusableMode); |
| } |
| } else if (direction == View.FOCUS_RIGHT){ |
| if (mCurrentPage < getPageCount() - 1) { |
| getPageAt(mCurrentPage + 1).addFocusables(views, direction, focusableMode); |
| } |
| } |
| } |
| |
| /** |
| * If one of our descendant views decides that it could be focused now, only |
| * pass that along if it's on the current page. |
| * |
| * This happens when live folders requery, and if they're off page, they |
| * end up calling requestFocus, which pulls it on page. |
| */ |
| @Override |
| public void focusableViewAvailable(View focused) { |
| View current = getPageAt(mCurrentPage); |
| View v = focused; |
| while (true) { |
| if (v == current) { |
| super.focusableViewAvailable(focused); |
| return; |
| } |
| if (v == this) { |
| return; |
| } |
| ViewParent parent = v.getParent(); |
| if (parent instanceof View) { |
| v = (View)v.getParent(); |
| } else { |
| return; |
| } |
| } |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public void requestDisallowInterceptTouchEvent(boolean disallowIntercept) { |
| if (disallowIntercept) { |
| // We need to make sure to cancel our long press if |
| // a scrollable widget takes over touch events |
| final View currentPage = getPageAt(mCurrentPage); |
| currentPage.cancelLongPress(); |
| } |
| super.requestDisallowInterceptTouchEvent(disallowIntercept); |
| } |
| |
| /** |
| * Return true if a tap at (x, y) should trigger a flip to the previous page. |
| */ |
| protected boolean hitsPreviousPage(float x, float y) { |
| return (x < getRelativeChildOffset(mCurrentPage) - mPageSpacing); |
| } |
| |
| /** |
| * Return true if a tap at (x, y) should trigger a flip to the next page. |
| */ |
| protected boolean hitsNextPage(float x, float y) { |
| return (x > (getMeasuredWidth() - getRelativeChildOffset(mCurrentPage) + mPageSpacing)); |
| } |
| |
| @Override |
| public boolean onInterceptTouchEvent(MotionEvent ev) { |
| /* |
| * This method JUST determines whether we want to intercept the motion. |
| * If we return true, onTouchEvent will be called and we do the actual |
| * scrolling there. |
| */ |
| acquireVelocityTrackerAndAddMovement(ev); |
| |
| // Skip touch handling if there are no pages to swipe |
| if (getChildCount() <= 0) return super.onInterceptTouchEvent(ev); |
| |
| /* |
| * Shortcut the most recurring case: the user is in the dragging |
| * state and he is moving his finger. We want to intercept this |
| * motion. |
| */ |
| final int action = ev.getAction(); |
| if ((action == MotionEvent.ACTION_MOVE) && |
| (mTouchState == TOUCH_STATE_SCROLLING)) { |
| return true; |
| } |
| |
| switch (action & MotionEvent.ACTION_MASK) { |
| 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. |
| */ |
| if (mActivePointerId != INVALID_POINTER) { |
| determineScrollingStart(ev); |
| break; |
| } |
| // if mActivePointerId is INVALID_POINTER, then we must have missed an ACTION_DOWN |
| // event. in that case, treat the first occurence of a move event as a ACTION_DOWN |
| // i.e. fall through to the next case (don't break) |
| // (We sometimes miss ACTION_DOWN events in Workspace because it ignores all events |
| // while it's small- this was causing a crash before we checked for INVALID_POINTER) |
| } |
| |
| case MotionEvent.ACTION_DOWN: { |
| final float x = ev.getX(); |
| final float y = ev.getY(); |
| // Remember location of down touch |
| mDownMotionX = x; |
| mLastMotionX = x; |
| mLastMotionY = y; |
| mLastMotionXRemainder = 0; |
| mTotalMotionX = 0; |
| mActivePointerId = ev.getPointerId(0); |
| mAllowLongPress = true; |
| |
| /* |
| * If being flinged and user touches the screen, initiate drag; |
| * otherwise don't. mScroller.isFinished should be false when |
| * being flinged. |
| */ |
| final int xDist = Math.abs(mScroller.getFinalX() - mScroller.getCurrX()); |
| final boolean finishedScrolling = (mScroller.isFinished() || xDist < mTouchSlop); |
| if (finishedScrolling) { |
| mTouchState = TOUCH_STATE_REST; |
| mScroller.abortAnimation(); |
| } else { |
| mTouchState = TOUCH_STATE_SCROLLING; |
| } |
| |
| // check if this can be the beginning of a tap on the side of the pages |
| // to scroll the current page |
| if (mTouchState != TOUCH_STATE_PREV_PAGE && mTouchState != TOUCH_STATE_NEXT_PAGE) { |
| if (getChildCount() > 0) { |
| if (hitsPreviousPage(x, y)) { |
| mTouchState = TOUCH_STATE_PREV_PAGE; |
| } else if (hitsNextPage(x, y)) { |
| mTouchState = TOUCH_STATE_NEXT_PAGE; |
| } |
| } |
| } |
| break; |
| } |
| |
| case MotionEvent.ACTION_UP: |
| case MotionEvent.ACTION_CANCEL: |
| mTouchState = TOUCH_STATE_REST; |
| mAllowLongPress = false; |
| mActivePointerId = INVALID_POINTER; |
| releaseVelocityTracker(); |
| break; |
| |
| case MotionEvent.ACTION_POINTER_UP: |
| onSecondaryPointerUp(ev); |
| releaseVelocityTracker(); |
| break; |
| } |
| |
| /* |
| * The only time we want to intercept motion events is if we are in the |
| * drag mode. |
| */ |
| return mTouchState != TOUCH_STATE_REST; |
| } |
| |
| protected void determineScrollingStart(MotionEvent ev) { |
| determineScrollingStart(ev, 1.0f); |
| } |
| |
| /* |
| * Determines if we should change the touch state to start scrolling after the |
| * user moves their touch point too far. |
| */ |
| protected void determineScrollingStart(MotionEvent ev, float touchSlopScale) { |
| /* |
| * Locally do absolute value. mLastMotionX is set to the y value |
| * of the down event. |
| */ |
| final int pointerIndex = ev.findPointerIndex(mActivePointerId); |
| if (pointerIndex == -1) { |
| return; |
| } |
| final float x = ev.getX(pointerIndex); |
| final float y = ev.getY(pointerIndex); |
| final int xDiff = (int) Math.abs(x - mLastMotionX); |
| final int yDiff = (int) Math.abs(y - mLastMotionY); |
| |
| final int touchSlop = Math.round(touchSlopScale * mTouchSlop); |
| boolean xPaged = xDiff > mPagingTouchSlop; |
| boolean xMoved = xDiff > touchSlop; |
| boolean yMoved = yDiff > touchSlop; |
| |
| if (xMoved || xPaged || yMoved) { |
| if (mUsePagingTouchSlop ? xPaged : xMoved) { |
| // Scroll if the user moved far enough along the X axis |
| mTouchState = TOUCH_STATE_SCROLLING; |
| mTotalMotionX += Math.abs(mLastMotionX - x); |
| mLastMotionX = x; |
| mLastMotionXRemainder = 0; |
| mTouchX = getScrollX(); |
| mSmoothingTime = System.nanoTime() / NANOTIME_DIV; |
| pageBeginMoving(); |
| } |
| // Either way, cancel any pending longpress |
| cancelCurrentPageLongPress(); |
| } |
| } |
| |
| protected void cancelCurrentPageLongPress() { |
| if (mAllowLongPress) { |
| mAllowLongPress = false; |
| // Try canceling the long press. It could also have been scheduled |
| // by a distant descendant, so use the mAllowLongPress flag to block |
| // everything |
| final View currentPage = getPageAt(mCurrentPage); |
| if (currentPage != null) { |
| currentPage.cancelLongPress(); |
| } |
| } |
| } |
| |
| protected float getScrollProgress(int screenCenter, View v, int page) { |
| final int halfScreenSize = getMeasuredWidth() / 2; |
| |
| int totalDistance = getScaledMeasuredWidth(v) + mPageSpacing; |
| int delta = screenCenter - (getChildOffset(page) - |
| getRelativeChildOffset(page) + halfScreenSize); |
| |
| float scrollProgress = delta / (totalDistance * 1.0f); |
| scrollProgress = Math.min(scrollProgress, 1.0f); |
| scrollProgress = Math.max(scrollProgress, -1.0f); |
| return scrollProgress; |
| } |
| |
| // This curve determines how the effect of scrolling over the limits of the page dimishes |
| // as the user pulls further and further from the bounds |
| private float overScrollInfluenceCurve(float f) { |
| f -= 1.0f; |
| return f * f * f + 1.0f; |
| } |
| |
| protected void acceleratedOverScroll(float amount) { |
| int screenSize = getMeasuredWidth(); |
| |
| // We want to reach the max over scroll effect when the user has |
| // over scrolled half the size of the screen |
| float f = OVERSCROLL_ACCELERATE_FACTOR * (amount / screenSize); |
| |
| if (f == 0) return; |
| |
| // Clamp this factor, f, to -1 < f < 1 |
| if (Math.abs(f) >= 1) { |
| f /= Math.abs(f); |
| } |
| |
| int overScrollAmount = (int) Math.round(f * screenSize); |
| if (amount < 0) { |
| mOverScrollX = overScrollAmount; |
| super.scrollTo(0, getScrollY()); |
| } else { |
| mOverScrollX = mMaxScrollX + overScrollAmount; |
| super.scrollTo(mMaxScrollX, getScrollY()); |
| } |
| invalidate(); |
| } |
| |
| protected void dampedOverScroll(float amount) { |
| int screenSize = getMeasuredWidth(); |
| |
| float f = (amount / screenSize); |
| |
| if (f == 0) return; |
| f = f / (Math.abs(f)) * (overScrollInfluenceCurve(Math.abs(f))); |
| |
| // Clamp this factor, f, to -1 < f < 1 |
| if (Math.abs(f) >= 1) { |
| f /= Math.abs(f); |
| } |
| |
| int overScrollAmount = (int) Math.round(OVERSCROLL_DAMP_FACTOR * f * screenSize); |
| if (amount < 0) { |
| mOverScrollX = overScrollAmount; |
| super.scrollTo(0, getScrollY()); |
| } else { |
| mOverScrollX = mMaxScrollX + overScrollAmount; |
| super.scrollTo(mMaxScrollX, getScrollY()); |
| } |
| invalidate(); |
| } |
| |
| protected void overScroll(float amount) { |
| dampedOverScroll(amount); |
| } |
| |
| protected float maxOverScroll() { |
| // Using the formula in overScroll, assuming that f = 1.0 (which it should generally not |
| // exceed). Used to find out how much extra wallpaper we need for the over scroll effect |
| float f = 1.0f; |
| f = f / (Math.abs(f)) * (overScrollInfluenceCurve(Math.abs(f))); |
| return OVERSCROLL_DAMP_FACTOR * f; |
| } |
| |
| @Override |
| public boolean onTouchEvent(MotionEvent ev) { |
| // Skip touch handling if there are no pages to swipe |
| if (getChildCount() <= 0) return super.onTouchEvent(ev); |
| |
| acquireVelocityTrackerAndAddMovement(ev); |
| |
| final int action = ev.getAction(); |
| |
| switch (action & MotionEvent.ACTION_MASK) { |
| case MotionEvent.ACTION_DOWN: |
| /* |
| * If being flinged and user touches, stop the fling. isFinished |
| * will be false if being flinged. |
| */ |
| if (!mScroller.isFinished()) { |
| mScroller.abortAnimation(); |
| } |
| |
| // Remember where the motion event started |
| mDownMotionX = mLastMotionX = ev.getX(); |
| mLastMotionXRemainder = 0; |
| mTotalMotionX = 0; |
| mActivePointerId = ev.getPointerId(0); |
| if (mTouchState == TOUCH_STATE_SCROLLING) { |
| pageBeginMoving(); |
| } |
| break; |
| |
| case MotionEvent.ACTION_MOVE: |
| if (mTouchState == TOUCH_STATE_SCROLLING) { |
| // Scroll to follow the motion event |
| final int pointerIndex = ev.findPointerIndex(mActivePointerId); |
| final float x = ev.getX(pointerIndex); |
| final float deltaX = mLastMotionX + mLastMotionXRemainder - x; |
| |
| mTotalMotionX += Math.abs(deltaX); |
| |
| // Only scroll and update mLastMotionX if we have moved some discrete amount. We |
| // keep the remainder because we are actually testing if we've moved from the last |
| // scrolled position (which is discrete). |
| if (Math.abs(deltaX) >= 1.0f) { |
| mTouchX += deltaX; |
| mSmoothingTime = System.nanoTime() / NANOTIME_DIV; |
| if (!mDeferScrollUpdate) { |
| scrollBy((int) deltaX, 0); |
| if (DEBUG) Log.d(TAG, "onTouchEvent().Scrolling: " + deltaX); |
| } else { |
| invalidate(); |
| } |
| mLastMotionX = x; |
| mLastMotionXRemainder = deltaX - (int) deltaX; |
| } else { |
| awakenScrollBars(); |
| } |
| } else { |
| determineScrollingStart(ev); |
| } |
| break; |
| |
| case MotionEvent.ACTION_UP: |
| if (mTouchState == TOUCH_STATE_SCROLLING) { |
| final int activePointerId = mActivePointerId; |
| final int pointerIndex = ev.findPointerIndex(activePointerId); |
| final float x = ev.getX(pointerIndex); |
| final VelocityTracker velocityTracker = mVelocityTracker; |
| velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); |
| int velocityX = (int) velocityTracker.getXVelocity(activePointerId); |
| final int deltaX = (int) (x - mDownMotionX); |
| final int pageWidth = getScaledMeasuredWidth(getPageAt(mCurrentPage)); |
| boolean isSignificantMove = Math.abs(deltaX) > pageWidth * |
| SIGNIFICANT_MOVE_THRESHOLD; |
| |
| mTotalMotionX += Math.abs(mLastMotionX + mLastMotionXRemainder - x); |
| |
| boolean isFling = mTotalMotionX > MIN_LENGTH_FOR_FLING && |
| Math.abs(velocityX) > mFlingThresholdVelocity; |
| |
| // In the case that the page is moved far to one direction and then is flung |
| // in the opposite direction, we use a threshold to determine whether we should |
| // just return to the starting page, or if we should skip one further. |
| boolean returnToOriginalPage = false; |
| if (Math.abs(deltaX) > pageWidth * RETURN_TO_ORIGINAL_PAGE_THRESHOLD && |
| Math.signum(velocityX) != Math.signum(deltaX) && isFling) { |
| returnToOriginalPage = true; |
| } |
| |
| int finalPage; |
| // We give flings precedence over large moves, which is why we short-circuit our |
| // test for a large move if a fling has been registered. That is, a large |
| // move to the left and fling to the right will register as a fling to the right. |
| if (((isSignificantMove && deltaX > 0 && !isFling) || |
| (isFling && velocityX > 0)) && mCurrentPage > 0) { |
| finalPage = returnToOriginalPage ? mCurrentPage : mCurrentPage - 1; |
| snapToPageWithVelocity(finalPage, velocityX); |
| } else if (((isSignificantMove && deltaX < 0 && !isFling) || |
| (isFling && velocityX < 0)) && |
| mCurrentPage < getChildCount() - 1) { |
| finalPage = returnToOriginalPage ? mCurrentPage : mCurrentPage + 1; |
| snapToPageWithVelocity(finalPage, velocityX); |
| } else { |
| snapToDestination(); |
| } |
| } else if (mTouchState == TOUCH_STATE_PREV_PAGE) { |
| // at this point we have not moved beyond the touch slop |
| // (otherwise mTouchState would be TOUCH_STATE_SCROLLING), so |
| // we can just page |
| int nextPage = Math.max(0, mCurrentPage - 1); |
| if (nextPage != mCurrentPage) { |
| snapToPage(nextPage); |
| } else { |
| snapToDestination(); |
| } |
| } else if (mTouchState == TOUCH_STATE_NEXT_PAGE) { |
| // at this point we have not moved beyond the touch slop |
| // (otherwise mTouchState would be TOUCH_STATE_SCROLLING), so |
| // we can just page |
| int nextPage = Math.min(getChildCount() - 1, mCurrentPage + 1); |
| if (nextPage != mCurrentPage) { |
| snapToPage(nextPage); |
| } else { |
| snapToDestination(); |
| } |
| } else { |
| onUnhandledTap(ev); |
| } |
| mTouchState = TOUCH_STATE_REST; |
| mActivePointerId = INVALID_POINTER; |
| releaseVelocityTracker(); |
| break; |
| |
| case MotionEvent.ACTION_CANCEL: |
| if (mTouchState == TOUCH_STATE_SCROLLING) { |
| snapToDestination(); |
| } |
| mTouchState = TOUCH_STATE_REST; |
| mActivePointerId = INVALID_POINTER; |
| releaseVelocityTracker(); |
| break; |
| |
| case MotionEvent.ACTION_POINTER_UP: |
| onSecondaryPointerUp(ev); |
| break; |
| } |
| |
| return true; |
| } |
| |
| @Override |
| public boolean onGenericMotionEvent(MotionEvent event) { |
| if ((event.getSource() & InputDevice.SOURCE_CLASS_POINTER) != 0) { |
| switch (event.getAction()) { |
| case MotionEvent.ACTION_SCROLL: { |
| // Handle mouse (or ext. device) by shifting the page depending on the scroll |
| final float vscroll; |
| final float hscroll; |
| if ((event.getMetaState() & KeyEvent.META_SHIFT_ON) != 0) { |
| vscroll = 0; |
| hscroll = event.getAxisValue(MotionEvent.AXIS_VSCROLL); |
| } else { |
| vscroll = -event.getAxisValue(MotionEvent.AXIS_VSCROLL); |
| hscroll = event.getAxisValue(MotionEvent.AXIS_HSCROLL); |
| } |
| if (hscroll != 0 || vscroll != 0) { |
| if (hscroll > 0 || vscroll > 0) { |
| scrollRight(); |
| } else { |
| scrollLeft(); |
| } |
| return true; |
| } |
| } |
| } |
| } |
| return super.onGenericMotionEvent(event); |
| } |
| |
| private void acquireVelocityTrackerAndAddMovement(MotionEvent ev) { |
| if (mVelocityTracker == null) { |
| mVelocityTracker = VelocityTracker.obtain(); |
| } |
| mVelocityTracker.addMovement(ev); |
| } |
| |
| private void releaseVelocityTracker() { |
| if (mVelocityTracker != null) { |
| mVelocityTracker.recycle(); |
| mVelocityTracker = null; |
| } |
| } |
| |
| private void onSecondaryPointerUp(MotionEvent ev) { |
| final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >> |
| MotionEvent.ACTION_POINTER_INDEX_SHIFT; |
| final int pointerId = ev.getPointerId(pointerIndex); |
| if (pointerId == mActivePointerId) { |
| // This was our active pointer going up. Choose a new |
| // active pointer and adjust accordingly. |
| // TODO: Make this decision more intelligent. |
| final int newPointerIndex = pointerIndex == 0 ? 1 : 0; |
| mLastMotionX = mDownMotionX = ev.getX(newPointerIndex); |
| mLastMotionY = ev.getY(newPointerIndex); |
| mLastMotionXRemainder = 0; |
| mActivePointerId = ev.getPointerId(newPointerIndex); |
| if (mVelocityTracker != null) { |
| mVelocityTracker.clear(); |
| } |
| } |
| } |
| |
| protected void onUnhandledTap(MotionEvent ev) {} |
| |
| @Override |
| public void requestChildFocus(View child, View focused) { |
| super.requestChildFocus(child, focused); |
| int page = indexToPage(indexOfChild(child)); |
| if (page >= 0 && page != getCurrentPage() && !isInTouchMode()) { |
| snapToPage(page); |
| } |
| } |
| |
| protected int getChildIndexForRelativeOffset(int relativeOffset) { |
| final int childCount = getChildCount(); |
| int left; |
| int right; |
| for (int i = 0; i < childCount; ++i) { |
| left = getRelativeChildOffset(i); |
| right = (left + getScaledMeasuredWidth(getPageAt(i))); |
| if (left <= relativeOffset && relativeOffset <= right) { |
| return i; |
| } |
| } |
| return -1; |
| } |
| |
| protected int getChildWidth(int index) { |
| // This functions are called enough times that it actually makes a difference in the |
| // profiler -- so just inline the max() here |
| final int measuredWidth = getPageAt(index).getMeasuredWidth(); |
| final int minWidth = mMinimumWidth; |
| return (minWidth > measuredWidth) ? minWidth : measuredWidth; |
| } |
| |
| int getPageNearestToCenterOfScreen() { |
| int minDistanceFromScreenCenter = Integer.MAX_VALUE; |
| int minDistanceFromScreenCenterIndex = -1; |
| int screenCenter = getScrollX() + (getMeasuredWidth() / 2); |
| final int childCount = getChildCount(); |
| for (int i = 0; i < childCount; ++i) { |
| View layout = (View) getPageAt(i); |
| int childWidth = getScaledMeasuredWidth(layout); |
| int halfChildWidth = (childWidth / 2); |
| int childCenter = getChildOffset(i) + halfChildWidth; |
| int distanceFromScreenCenter = Math.abs(childCenter - screenCenter); |
| if (distanceFromScreenCenter < minDistanceFromScreenCenter) { |
| minDistanceFromScreenCenter = distanceFromScreenCenter; |
| minDistanceFromScreenCenterIndex = i; |
| } |
| } |
| return minDistanceFromScreenCenterIndex; |
| } |
| |
| protected void snapToDestination() { |
| snapToPage(getPageNearestToCenterOfScreen(), PAGE_SNAP_ANIMATION_DURATION); |
| } |
| |
| private static class ScrollInterpolator implements Interpolator { |
| public ScrollInterpolator() { |
| } |
| |
| public float getInterpolation(float t) { |
| t -= 1.0f; |
| return t*t*t*t*t + 1; |
| } |
| } |
| |
| // 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); |
| } |
| |
| protected void snapToPageWithVelocity(int whichPage, int velocity) { |
| whichPage = Math.max(0, Math.min(whichPage, getChildCount() - 1)); |
| int halfScreenSize = getMeasuredWidth() / 2; |
| |
| if (DEBUG) Log.d(TAG, "snapToPage.getChildOffset(): " + getChildOffset(whichPage)); |
| if (DEBUG) Log.d(TAG, "snapToPageWithVelocity.getRelativeChildOffset(): " |
| + getMeasuredWidth() + ", " + getChildWidth(whichPage)); |
| final int newX = getChildOffset(whichPage) - getRelativeChildOffset(whichPage); |
| int delta = newX - mUnboundedScrollX; |
| int duration = 0; |
| |
| if (Math.abs(velocity) < mMinFlingVelocity) { |
| // If the velocity is low enough, then treat this more as an automatic page advance |
| // as opposed to an apparent physical response to flinging |
| snapToPage(whichPage, PAGE_SNAP_ANIMATION_DURATION); |
| return; |
| } |
| |
| // Here we compute a "distance" that will be used in the computation of the overall |
| // snap duration. This is a function of the actual distance that needs to be traveled; |
| // we keep this value close to half screen size in order to reduce the variance in snap |
| // duration as a function of the distance the page needs to travel. |
| float distanceRatio = Math.min(1f, 1.0f * Math.abs(delta) / (2 * halfScreenSize)); |
| float distance = halfScreenSize + halfScreenSize * |
| distanceInfluenceForSnapDuration(distanceRatio); |
| |
| velocity = Math.abs(velocity); |
| velocity = Math.max(mMinSnapVelocity, velocity); |
| |
| // we want the page's snap velocity to approximately match the velocity at which the |
| // user flings, so we scale the duration by a value near to the derivative of the scroll |
| // interpolator at zero, ie. 5. We use 4 to make it a little slower. |
| duration = 4 * Math.round(1000 * Math.abs(distance / velocity)); |
| |
| snapToPage(whichPage, delta, duration); |
| } |
| |
| protected void snapToPage(int whichPage) { |
| snapToPage(whichPage, PAGE_SNAP_ANIMATION_DURATION); |
| } |
| |
| protected void snapToPage(int whichPage, int duration) { |
| whichPage = Math.max(0, Math.min(whichPage, getPageCount() - 1)); |
| |
| if (DEBUG) Log.d(TAG, "snapToPage.getChildOffset(): " + getChildOffset(whichPage)); |
| if (DEBUG) Log.d(TAG, "snapToPage.getRelativeChildOffset(): " + getMeasuredWidth() + ", " |
| + getChildWidth(whichPage)); |
| int newX = getChildOffset(whichPage) - getRelativeChildOffset(whichPage); |
| final int sX = mUnboundedScrollX; |
| final int delta = newX - sX; |
| snapToPage(whichPage, delta, duration); |
| } |
| |
| protected void snapToPage(int whichPage, int delta, int duration) { |
| mNextPage = whichPage; |
| |
| View focusedChild = getFocusedChild(); |
| if (focusedChild != null && whichPage != mCurrentPage && |
| focusedChild == getPageAt(mCurrentPage)) { |
| focusedChild.clearFocus(); |
| } |
| |
| pageBeginMoving(); |
| awakenScrollBars(duration); |
| if (duration == 0) { |
| duration = Math.abs(delta); |
| } |
| |
| if (!mScroller.isFinished()) mScroller.abortAnimation(); |
| mScroller.startScroll(mUnboundedScrollX, 0, delta, 0, duration); |
| |
| // Load associated pages immediately if someone else is handling the scroll, otherwise defer |
| // loading associated pages until the scroll settles |
| if (mDeferScrollUpdate) { |
| loadAssociatedPages(mNextPage); |
| } else { |
| mDeferLoadAssociatedPagesUntilScrollCompletes = true; |
| } |
| notifyPageSwitchListener(); |
| invalidate(); |
| } |
| |
| public void scrollLeft() { |
| if (mScroller.isFinished()) { |
| if (mCurrentPage > 0) snapToPage(mCurrentPage - 1); |
| } else { |
| if (mNextPage > 0) snapToPage(mNextPage - 1); |
| } |
| } |
| |
| public void scrollRight() { |
| if (mScroller.isFinished()) { |
| if (mCurrentPage < getChildCount() -1) snapToPage(mCurrentPage + 1); |
| } else { |
| if (mNextPage < getChildCount() -1) snapToPage(mNextPage + 1); |
| } |
| } |
| |
| public int getPageForView(View v) { |
| int result = -1; |
| if (v != null) { |
| ViewParent vp = v.getParent(); |
| int count = getChildCount(); |
| for (int i = 0; i < count; i++) { |
| if (vp == getPageAt(i)) { |
| return i; |
| } |
| } |
| } |
| return result; |
| } |
| |
| /** |
| * @return True is long presses are still allowed for the current touch |
| */ |
| public boolean allowLongPress() { |
| return mAllowLongPress; |
| } |
| |
| /** |
| * Set true to allow long-press events to be triggered, usually checked by |
| * {@link Launcher} to accept or block dpad-initiated long-presses. |
| */ |
| public void setAllowLongPress(boolean allowLongPress) { |
| mAllowLongPress = allowLongPress; |
| } |
| |
| public static class SavedState extends BaseSavedState { |
| int currentPage = -1; |
| |
| SavedState(Parcelable superState) { |
| super(superState); |
| } |
| |
| private SavedState(Parcel in) { |
| super(in); |
| currentPage = in.readInt(); |
| } |
| |
| @Override |
| public void writeToParcel(Parcel out, int flags) { |
| super.writeToParcel(out, flags); |
| out.writeInt(currentPage); |
| } |
| |
| public static final Parcelable.Creator<SavedState> CREATOR = |
| new Parcelable.Creator<SavedState>() { |
| public SavedState createFromParcel(Parcel in) { |
| return new SavedState(in); |
| } |
| |
| public SavedState[] newArray(int size) { |
| return new SavedState[size]; |
| } |
| }; |
| } |
| |
| protected void loadAssociatedPages(int page) { |
| loadAssociatedPages(page, false); |
| } |
| protected void loadAssociatedPages(int page, boolean immediateAndOnly) { |
| if (mContentIsRefreshable) { |
| final int count = getChildCount(); |
| if (page < count) { |
| int lowerPageBound = getAssociatedLowerPageBound(page); |
| int upperPageBound = getAssociatedUpperPageBound(page); |
| if (DEBUG) Log.d(TAG, "loadAssociatedPages: " + lowerPageBound + "/" |
| + upperPageBound); |
| // First, clear any pages that should no longer be loaded |
| for (int i = 0; i < count; ++i) { |
| Page layout = (Page) getPageAt(i); |
| if ((i < lowerPageBound) || (i > upperPageBound)) { |
| if (layout.getPageChildCount() > 0) { |
| layout.removeAllViewsOnPage(); |
| } |
| mDirtyPageContent.set(i, true); |
| } |
| } |
| // Next, load any new pages |
| for (int i = 0; i < count; ++i) { |
| if ((i != page) && immediateAndOnly) { |
| continue; |
| } |
| if (lowerPageBound <= i && i <= upperPageBound) { |
| if (mDirtyPageContent.get(i)) { |
| syncPageItems(i, (i == page) && immediateAndOnly); |
| mDirtyPageContent.set(i, false); |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| protected int getAssociatedLowerPageBound(int page) { |
| return Math.max(0, page - 1); |
| } |
| protected int getAssociatedUpperPageBound(int page) { |
| final int count = getChildCount(); |
| return Math.min(page + 1, count - 1); |
| } |
| |
| /** |
| * This method is called ONLY to synchronize the number of pages that the paged view has. |
| * To actually fill the pages with information, implement syncPageItems() below. It is |
| * guaranteed that syncPageItems() will be called for a particular page before it is shown, |
| * and therefore, individual page items do not need to be updated in this method. |
| */ |
| public abstract void syncPages(); |
| |
| /** |
| * This method is called to synchronize the items that are on a particular page. If views on |
| * the page can be reused, then they should be updated within this method. |
| */ |
| public abstract void syncPageItems(int page, boolean immediate); |
| |
| protected void invalidatePageData() { |
| invalidatePageData(-1, false); |
| } |
| protected void invalidatePageData(int currentPage) { |
| invalidatePageData(currentPage, false); |
| } |
| protected void invalidatePageData(int currentPage, boolean immediateAndOnly) { |
| if (!mIsDataReady) { |
| return; |
| } |
| |
| if (mContentIsRefreshable) { |
| // Force all scrolling-related behavior to end |
| mScroller.forceFinished(true); |
| mNextPage = INVALID_PAGE; |
| |
| // Update all the pages |
| syncPages(); |
| |
| // We must force a measure after we've loaded the pages to update the content width and |
| // to determine the full scroll width |
| measure(MeasureSpec.makeMeasureSpec(getMeasuredWidth(), MeasureSpec.EXACTLY), |
| MeasureSpec.makeMeasureSpec(getMeasuredHeight(), MeasureSpec.EXACTLY)); |
| |
| // Set a new page as the current page if necessary |
| if (currentPage > -1) { |
| setCurrentPage(Math.min(getPageCount() - 1, currentPage)); |
| } |
| |
| // Mark each of the pages as dirty |
| final int count = getChildCount(); |
| mDirtyPageContent.clear(); |
| for (int i = 0; i < count; ++i) { |
| mDirtyPageContent.add(true); |
| } |
| |
| // Load any pages that are necessary for the current window of views |
| loadAssociatedPages(mCurrentPage, immediateAndOnly); |
| requestLayout(); |
| } |
| } |
| |
| protected View getScrollingIndicator() { |
| // We use mHasScrollIndicator to prevent future lookups if there is no sibling indicator |
| // found |
| if (mHasScrollIndicator && mScrollIndicator == null) { |
| ViewGroup parent = (ViewGroup) getParent(); |
| if (parent != null) { |
| mScrollIndicator = (View) (parent.findViewById(R.id.paged_view_indicator)); |
| mHasScrollIndicator = mScrollIndicator != null; |
| if (mHasScrollIndicator) { |
| mScrollIndicator.setVisibility(View.VISIBLE); |
| } |
| } |
| } |
| return mScrollIndicator; |
| } |
| |
| protected boolean isScrollingIndicatorEnabled() { |
| return !LauncherApplication.isScreenLarge(); |
| } |
| |
| Runnable hideScrollingIndicatorRunnable = new Runnable() { |
| @Override |
| public void run() { |
| hideScrollingIndicator(false); |
| } |
| }; |
| protected void flashScrollingIndicator(boolean animated) { |
| removeCallbacks(hideScrollingIndicatorRunnable); |
| showScrollingIndicator(!animated); |
| postDelayed(hideScrollingIndicatorRunnable, sScrollIndicatorFlashDuration); |
| } |
| |
| protected void showScrollingIndicator(boolean immediately) { |
| mShouldShowScrollIndicator = true; |
| mShouldShowScrollIndicatorImmediately = true; |
| if (getChildCount() <= 1) return; |
| if (!isScrollingIndicatorEnabled()) return; |
| |
| mShouldShowScrollIndicator = false; |
| getScrollingIndicator(); |
| if (mScrollIndicator != null) { |
| // Fade the indicator in |
| updateScrollingIndicatorPosition(); |
| mScrollIndicator.setVisibility(View.VISIBLE); |
| cancelScrollingIndicatorAnimations(); |
| if (immediately) { |
| mScrollIndicator.setAlpha(1f); |
| } else { |
| mScrollIndicatorAnimator = ObjectAnimator.ofFloat(mScrollIndicator, "alpha", 1f); |
| mScrollIndicatorAnimator.setDuration(sScrollIndicatorFadeInDuration); |
| mScrollIndicatorAnimator.start(); |
| } |
| } |
| } |
| |
| protected void cancelScrollingIndicatorAnimations() { |
| if (mScrollIndicatorAnimator != null) { |
| mScrollIndicatorAnimator.cancel(); |
| } |
| } |
| |
| protected void hideScrollingIndicator(boolean immediately) { |
| if (getChildCount() <= 1) return; |
| if (!isScrollingIndicatorEnabled()) return; |
| |
| getScrollingIndicator(); |
| if (mScrollIndicator != null) { |
| // Fade the indicator out |
| updateScrollingIndicatorPosition(); |
| cancelScrollingIndicatorAnimations(); |
| if (immediately) { |
| mScrollIndicator.setVisibility(View.INVISIBLE); |
| mScrollIndicator.setAlpha(0f); |
| } else { |
| mScrollIndicatorAnimator = ObjectAnimator.ofFloat(mScrollIndicator, "alpha", 0f); |
| mScrollIndicatorAnimator.setDuration(sScrollIndicatorFadeOutDuration); |
| mScrollIndicatorAnimator.addListener(new AnimatorListenerAdapter() { |
| private boolean cancelled = false; |
| @Override |
| public void onAnimationCancel(android.animation.Animator animation) { |
| cancelled = true; |
| } |
| @Override |
| public void onAnimationEnd(Animator animation) { |
| if (!cancelled) { |
| mScrollIndicator.setVisibility(View.INVISIBLE); |
| } |
| } |
| }); |
| mScrollIndicatorAnimator.start(); |
| } |
| } |
| } |
| |
| /** |
| * To be overridden by subclasses to determine whether the scroll indicator should stretch to |
| * fill its space on the track or not. |
| */ |
| protected boolean hasElasticScrollIndicator() { |
| return true; |
| } |
| |
| private void updateScrollingIndicator() { |
| if (getChildCount() <= 1) return; |
| if (!isScrollingIndicatorEnabled()) return; |
| |
| getScrollingIndicator(); |
| if (mScrollIndicator != null) { |
| updateScrollingIndicatorPosition(); |
| } |
| if (mShouldShowScrollIndicator) { |
| showScrollingIndicator(mShouldShowScrollIndicatorImmediately); |
| } |
| } |
| |
| private void updateScrollingIndicatorPosition() { |
| if (!isScrollingIndicatorEnabled()) return; |
| if (mScrollIndicator == null) return; |
| int numPages = getChildCount(); |
| int pageWidth = getMeasuredWidth(); |
| int lastChildIndex = Math.max(0, getChildCount() - 1); |
| int maxScrollX = getChildOffset(lastChildIndex) - getRelativeChildOffset(lastChildIndex); |
| int trackWidth = pageWidth - mScrollIndicatorPaddingLeft - mScrollIndicatorPaddingRight; |
| int indicatorWidth = mScrollIndicator.getMeasuredWidth() - |
| mScrollIndicator.getPaddingLeft() - mScrollIndicator.getPaddingRight(); |
| |
| float offset = Math.max(0f, Math.min(1f, (float) getScrollX() / maxScrollX)); |
| int indicatorSpace = trackWidth / numPages; |
| int indicatorPos = (int) (offset * (trackWidth - indicatorSpace)) + mScrollIndicatorPaddingLeft; |
| if (hasElasticScrollIndicator()) { |
| if (mScrollIndicator.getMeasuredWidth() != indicatorSpace) { |
| mScrollIndicator.getLayoutParams().width = indicatorSpace; |
| mScrollIndicator.requestLayout(); |
| } |
| } else { |
| int indicatorCenterOffset = indicatorSpace / 2 - indicatorWidth / 2; |
| indicatorPos += indicatorCenterOffset; |
| } |
| mScrollIndicator.setTranslationX(indicatorPos); |
| } |
| |
| public void showScrollIndicatorTrack() { |
| } |
| |
| public void hideScrollIndicatorTrack() { |
| } |
| |
| /* Accessibility */ |
| @Override |
| public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { |
| super.onInitializeAccessibilityNodeInfo(info); |
| info.setScrollable(getPageCount() > 1); |
| if (getCurrentPage() < getPageCount() - 1) { |
| info.addAction(AccessibilityNodeInfo.ACTION_SCROLL_FORWARD); |
| } |
| if (getCurrentPage() > 0) { |
| info.addAction(AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD); |
| } |
| } |
| |
| @Override |
| public void onInitializeAccessibilityEvent(AccessibilityEvent event) { |
| super.onInitializeAccessibilityEvent(event); |
| event.setScrollable(true); |
| if (event.getEventType() == AccessibilityEvent.TYPE_VIEW_SCROLLED) { |
| event.setFromIndex(mCurrentPage); |
| event.setToIndex(mCurrentPage); |
| event.setItemCount(getChildCount()); |
| } |
| } |
| |
| @Override |
| public boolean performAccessibilityAction(int action, Bundle arguments) { |
| if (super.performAccessibilityAction(action, arguments)) { |
| return true; |
| } |
| switch (action) { |
| case AccessibilityNodeInfo.ACTION_SCROLL_FORWARD: { |
| if (getCurrentPage() < getPageCount() - 1) { |
| scrollRight(); |
| return true; |
| } |
| } break; |
| case AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD: { |
| if (getCurrentPage() > 0) { |
| scrollLeft(); |
| return true; |
| } |
| } break; |
| } |
| return false; |
| } |
| |
| protected String getCurrentPageDescription() { |
| return String.format(getContext().getString(R.string.default_scroll_format), |
| getNextPage() + 1, getChildCount()); |
| } |
| |
| @Override |
| public boolean onHoverEvent(android.view.MotionEvent event) { |
| return true; |
| } |
| } |
