| /* |
| * Copyright (C) 2006 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.widget; |
| |
| import android.annotation.ColorInt; |
| import android.annotation.NonNull; |
| import android.compat.annotation.UnsupportedAppUsage; |
| import android.content.Context; |
| import android.content.res.Configuration; |
| import android.content.res.TypedArray; |
| import android.graphics.Canvas; |
| import android.graphics.Rect; |
| import android.os.Build; |
| import android.os.Build.VERSION_CODES; |
| import android.os.Bundle; |
| import android.os.Parcel; |
| import android.os.Parcelable; |
| import android.os.StrictMode; |
| import android.util.AttributeSet; |
| import android.util.Log; |
| import android.view.FocusFinder; |
| 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.ViewDebug; |
| import android.view.ViewGroup; |
| import android.view.ViewHierarchyEncoder; |
| import android.view.ViewParent; |
| import android.view.accessibility.AccessibilityEvent; |
| import android.view.accessibility.AccessibilityNodeInfo; |
| import android.view.animation.AnimationUtils; |
| import android.view.inspector.InspectableProperty; |
| |
| import com.android.internal.R; |
| |
| import java.util.List; |
| |
| /** |
| * A view group that allows the view hierarchy placed within it to be scrolled. |
| * Scroll view may have only one direct child placed within it. |
| * To add multiple views within the scroll view, make |
| * the direct child you add a view group, for example {@link LinearLayout}, and |
| * place additional views within that LinearLayout. |
| * |
| * <p>Scroll view supports vertical scrolling only. For horizontal scrolling, |
| * use {@link HorizontalScrollView} instead.</p> |
| * |
| * <p>Never add a {@link android.support.v7.widget.RecyclerView} or {@link ListView} to |
| * a scroll view. Doing so results in poor user interface performance and a poor user |
| * experience.</p> |
| * |
| * <p class="note"> |
| * For vertical scrolling, consider {@link android.support.v4.widget.NestedScrollView} |
| * instead of scroll view which offers greater user interface flexibility and |
| * support for the material design scrolling patterns.</p> |
| * |
| * <p>Material Design offers guidelines on how the appearance of |
| * <a href="https://material.io/components/">several UI components</a>, including app bars and |
| * banners, should respond to gestures.</p> |
| * |
| * @attr ref android.R.styleable#ScrollView_fillViewport |
| */ |
| public class ScrollView extends FrameLayout { |
| static final int ANIMATED_SCROLL_GAP = 250; |
| |
| static final float MAX_SCROLL_FACTOR = 0.5f; |
| |
| private static final String TAG = "ScrollView"; |
| |
| @UnsupportedAppUsage |
| private long mLastScroll; |
| |
| private final Rect mTempRect = new Rect(); |
| @UnsupportedAppUsage |
| private OverScroller mScroller; |
| /** |
| * Tracks the state of the top edge glow. |
| * |
| * Even though this field is practically final, we cannot make it final because there are apps |
| * setting it via reflection and they need to keep working until they target Q. |
| */ |
| @NonNull |
| @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 123768600) |
| private EdgeEffect mEdgeGlowTop = new EdgeEffect(getContext()); |
| |
| /** |
| * Tracks the state of the bottom edge glow. |
| * |
| * Even though this field is practically final, we cannot make it final because there are apps |
| * setting it via reflection and they need to keep working until they target Q. |
| */ |
| @NonNull |
| @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 123769386) |
| private EdgeEffect mEdgeGlowBottom = new EdgeEffect(getContext()); |
| |
| /** |
| * Position of the last motion event. |
| */ |
| @UnsupportedAppUsage |
| private int mLastMotionY; |
| |
| /** |
| * True when the layout has changed but the traversal has not come through yet. |
| * Ideally the view hierarchy would keep track of this for us. |
| */ |
| private boolean mIsLayoutDirty = true; |
| |
| /** |
| * The child to give focus to in the event that a child has requested focus while the |
| * layout is dirty. This prevents the scroll from being wrong if the child has not been |
| * laid out before requesting focus. |
| */ |
| @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 123769715) |
| private View mChildToScrollTo = null; |
| |
| /** |
| * True if the user is currently dragging this ScrollView around. This is |
| * not the same as 'is being flinged', which can be checked by |
| * mScroller.isFinished() (flinging begins when the user lifts his finger). |
| */ |
| @UnsupportedAppUsage |
| private boolean mIsBeingDragged = false; |
| |
| /** |
| * Determines speed during touch scrolling |
| */ |
| @UnsupportedAppUsage |
| private VelocityTracker mVelocityTracker; |
| |
| /** |
| * When set to true, the scroll view measure its child to make it fill the currently |
| * visible area. |
| */ |
| @ViewDebug.ExportedProperty(category = "layout") |
| private boolean mFillViewport; |
| |
| /** |
| * Whether arrow scrolling is animated. |
| */ |
| private boolean mSmoothScrollingEnabled = true; |
| |
| private int mTouchSlop; |
| @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 124051125) |
| private int mMinimumVelocity; |
| private int mMaximumVelocity; |
| |
| @UnsupportedAppUsage(maxTargetSdk = VERSION_CODES.P, trackingBug = 124050903) |
| private int mOverscrollDistance; |
| @UnsupportedAppUsage(maxTargetSdk = VERSION_CODES.P, trackingBug = 124050903) |
| private int mOverflingDistance; |
| |
| private float mVerticalScrollFactor; |
| |
| /** |
| * ID of the active pointer. This is used to retain consistency during |
| * drags/flings if multiple pointers are used. |
| */ |
| private int mActivePointerId = INVALID_POINTER; |
| |
| /** |
| * Used during scrolling to retrieve the new offset within the window. |
| */ |
| private final int[] mScrollOffset = new int[2]; |
| private final int[] mScrollConsumed = new int[2]; |
| private int mNestedYOffset; |
| |
| /** |
| * The StrictMode "critical time span" objects to catch animation |
| * stutters. Non-null when a time-sensitive animation is |
| * in-flight. Must call finish() on them when done animating. |
| * These are no-ops on user builds. |
| */ |
| private StrictMode.Span mScrollStrictSpan = null; // aka "drag" |
| @UnsupportedAppUsage |
| private StrictMode.Span mFlingStrictSpan = null; |
| |
| /** |
| * Sentinel value for no current active pointer. |
| * Used by {@link #mActivePointerId}. |
| */ |
| private static final int INVALID_POINTER = -1; |
| |
| private SavedState mSavedState; |
| |
| public ScrollView(Context context) { |
| this(context, null); |
| } |
| |
| public ScrollView(Context context, AttributeSet attrs) { |
| this(context, attrs, com.android.internal.R.attr.scrollViewStyle); |
| } |
| |
| public ScrollView(Context context, AttributeSet attrs, int defStyleAttr) { |
| this(context, attrs, defStyleAttr, 0); |
| } |
| |
| public ScrollView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { |
| super(context, attrs, defStyleAttr, defStyleRes); |
| initScrollView(); |
| |
| final TypedArray a = context.obtainStyledAttributes( |
| attrs, com.android.internal.R.styleable.ScrollView, defStyleAttr, defStyleRes); |
| saveAttributeDataForStyleable(context, com.android.internal.R.styleable.ScrollView, |
| attrs, a, defStyleAttr, defStyleRes); |
| |
| setFillViewport(a.getBoolean(R.styleable.ScrollView_fillViewport, false)); |
| |
| a.recycle(); |
| |
| if (context.getResources().getConfiguration().uiMode == Configuration.UI_MODE_TYPE_WATCH) { |
| setRevealOnFocusHint(false); |
| } |
| } |
| |
| @Override |
| public boolean shouldDelayChildPressedState() { |
| return true; |
| } |
| |
| @Override |
| protected float getTopFadingEdgeStrength() { |
| if (getChildCount() == 0) { |
| return 0.0f; |
| } |
| |
| final int length = getVerticalFadingEdgeLength(); |
| if (mScrollY < length) { |
| return mScrollY / (float) length; |
| } |
| |
| return 1.0f; |
| } |
| |
| @Override |
| protected float getBottomFadingEdgeStrength() { |
| if (getChildCount() == 0) { |
| return 0.0f; |
| } |
| |
| final int length = getVerticalFadingEdgeLength(); |
| final int bottomEdge = getHeight() - mPaddingBottom; |
| final int span = getChildAt(0).getBottom() - mScrollY - bottomEdge; |
| if (span < length) { |
| return span / (float) length; |
| } |
| |
| return 1.0f; |
| } |
| |
| /** |
| * Sets the edge effect color for both top and bottom edge effects. |
| * |
| * @param color The color for the edge effects. |
| * @see #setTopEdgeEffectColor(int) |
| * @see #setBottomEdgeEffectColor(int) |
| * @see #getTopEdgeEffectColor() |
| * @see #getBottomEdgeEffectColor() |
| */ |
| public void setEdgeEffectColor(@ColorInt int color) { |
| setTopEdgeEffectColor(color); |
| setBottomEdgeEffectColor(color); |
| } |
| |
| /** |
| * Sets the bottom edge effect color. |
| * |
| * @param color The color for the bottom edge effect. |
| * @see #setTopEdgeEffectColor(int) |
| * @see #setEdgeEffectColor(int) |
| * @see #getTopEdgeEffectColor() |
| * @see #getBottomEdgeEffectColor() |
| */ |
| public void setBottomEdgeEffectColor(@ColorInt int color) { |
| mEdgeGlowBottom.setColor(color); |
| } |
| |
| /** |
| * Sets the top edge effect color. |
| * |
| * @param color The color for the top edge effect. |
| * @see #setBottomEdgeEffectColor(int) |
| * @see #setEdgeEffectColor(int) |
| * @see #getTopEdgeEffectColor() |
| * @see #getBottomEdgeEffectColor() |
| */ |
| public void setTopEdgeEffectColor(@ColorInt int color) { |
| mEdgeGlowTop.setColor(color); |
| } |
| |
| /** |
| * Returns the top edge effect color. |
| * |
| * @return The top edge effect color. |
| * @see #setEdgeEffectColor(int) |
| * @see #setTopEdgeEffectColor(int) |
| * @see #setBottomEdgeEffectColor(int) |
| * @see #getBottomEdgeEffectColor() |
| */ |
| @ColorInt |
| public int getTopEdgeEffectColor() { |
| return mEdgeGlowTop.getColor(); |
| } |
| |
| /** |
| * Returns the bottom edge effect color. |
| * |
| * @return The bottom edge effect color. |
| * @see #setEdgeEffectColor(int) |
| * @see #setTopEdgeEffectColor(int) |
| * @see #setBottomEdgeEffectColor(int) |
| * @see #getTopEdgeEffectColor() |
| */ |
| @ColorInt |
| public int getBottomEdgeEffectColor() { |
| return mEdgeGlowBottom.getColor(); |
| } |
| |
| /** |
| * @return The maximum amount this scroll view will scroll in response to |
| * an arrow event. |
| */ |
| public int getMaxScrollAmount() { |
| return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); |
| } |
| |
| |
| private void initScrollView() { |
| mScroller = new OverScroller(getContext()); |
| setFocusable(true); |
| setDescendantFocusability(FOCUS_AFTER_DESCENDANTS); |
| setWillNotDraw(false); |
| final ViewConfiguration configuration = ViewConfiguration.get(mContext); |
| mTouchSlop = configuration.getScaledTouchSlop(); |
| mMinimumVelocity = configuration.getScaledMinimumFlingVelocity(); |
| mMaximumVelocity = configuration.getScaledMaximumFlingVelocity(); |
| mOverscrollDistance = configuration.getScaledOverscrollDistance(); |
| mOverflingDistance = configuration.getScaledOverflingDistance(); |
| mVerticalScrollFactor = configuration.getScaledVerticalScrollFactor(); |
| } |
| |
| @Override |
| public void addView(View child) { |
| if (getChildCount() > 0) { |
| throw new IllegalStateException("ScrollView can host only one direct child"); |
| } |
| |
| super.addView(child); |
| } |
| |
| @Override |
| public void addView(View child, int index) { |
| if (getChildCount() > 0) { |
| throw new IllegalStateException("ScrollView can host only one direct child"); |
| } |
| |
| super.addView(child, index); |
| } |
| |
| @Override |
| public void addView(View child, ViewGroup.LayoutParams params) { |
| if (getChildCount() > 0) { |
| throw new IllegalStateException("ScrollView can host only one direct child"); |
| } |
| |
| super.addView(child, params); |
| } |
| |
| @Override |
| public void addView(View child, int index, ViewGroup.LayoutParams params) { |
| if (getChildCount() > 0) { |
| throw new IllegalStateException("ScrollView can host only one direct child"); |
| } |
| |
| super.addView(child, index, params); |
| } |
| |
| /** |
| * @return Returns true this ScrollView can be scrolled |
| */ |
| @UnsupportedAppUsage |
| private boolean canScroll() { |
| View child = getChildAt(0); |
| if (child != null) { |
| int childHeight = child.getHeight(); |
| return getHeight() < childHeight + mPaddingTop + mPaddingBottom; |
| } |
| return false; |
| } |
| |
| /** |
| * Indicates whether this ScrollView's content is stretched to fill the viewport. |
| * |
| * @return True if the content fills the viewport, false otherwise. |
| * |
| * @attr ref android.R.styleable#ScrollView_fillViewport |
| */ |
| @InspectableProperty |
| public boolean isFillViewport() { |
| return mFillViewport; |
| } |
| |
| /** |
| * Indicates this ScrollView whether it should stretch its content height to fill |
| * the viewport or not. |
| * |
| * @param fillViewport True to stretch the content's height to the viewport's |
| * boundaries, false otherwise. |
| * |
| * @attr ref android.R.styleable#ScrollView_fillViewport |
| */ |
| public void setFillViewport(boolean fillViewport) { |
| if (fillViewport != mFillViewport) { |
| mFillViewport = fillViewport; |
| requestLayout(); |
| } |
| } |
| |
| /** |
| * @return Whether arrow scrolling will animate its transition. |
| */ |
| public boolean isSmoothScrollingEnabled() { |
| return mSmoothScrollingEnabled; |
| } |
| |
| /** |
| * Set whether arrow scrolling will animate its transition. |
| * @param smoothScrollingEnabled whether arrow scrolling will animate its transition |
| */ |
| public void setSmoothScrollingEnabled(boolean smoothScrollingEnabled) { |
| mSmoothScrollingEnabled = smoothScrollingEnabled; |
| } |
| |
| @Override |
| protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { |
| super.onMeasure(widthMeasureSpec, heightMeasureSpec); |
| |
| if (!mFillViewport) { |
| return; |
| } |
| |
| final int heightMode = MeasureSpec.getMode(heightMeasureSpec); |
| if (heightMode == MeasureSpec.UNSPECIFIED) { |
| return; |
| } |
| |
| if (getChildCount() > 0) { |
| final View child = getChildAt(0); |
| final int widthPadding; |
| final int heightPadding; |
| final int targetSdkVersion = getContext().getApplicationInfo().targetSdkVersion; |
| final FrameLayout.LayoutParams lp = (LayoutParams) child.getLayoutParams(); |
| if (targetSdkVersion >= VERSION_CODES.M) { |
| widthPadding = mPaddingLeft + mPaddingRight + lp.leftMargin + lp.rightMargin; |
| heightPadding = mPaddingTop + mPaddingBottom + lp.topMargin + lp.bottomMargin; |
| } else { |
| widthPadding = mPaddingLeft + mPaddingRight; |
| heightPadding = mPaddingTop + mPaddingBottom; |
| } |
| |
| final int desiredHeight = getMeasuredHeight() - heightPadding; |
| if (child.getMeasuredHeight() < desiredHeight) { |
| final int childWidthMeasureSpec = getChildMeasureSpec( |
| widthMeasureSpec, widthPadding, lp.width); |
| final int childHeightMeasureSpec = MeasureSpec.makeMeasureSpec( |
| desiredHeight, MeasureSpec.EXACTLY); |
| child.measure(childWidthMeasureSpec, childHeightMeasureSpec); |
| } |
| } |
| } |
| |
| @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) { |
| mTempRect.setEmpty(); |
| |
| if (!canScroll()) { |
| if (isFocused() && event.getKeyCode() != KeyEvent.KEYCODE_BACK) { |
| View currentFocused = findFocus(); |
| if (currentFocused == this) currentFocused = null; |
| View nextFocused = FocusFinder.getInstance().findNextFocus(this, |
| currentFocused, View.FOCUS_DOWN); |
| return nextFocused != null |
| && nextFocused != this |
| && nextFocused.requestFocus(View.FOCUS_DOWN); |
| } |
| return false; |
| } |
| |
| boolean handled = false; |
| if (event.getAction() == KeyEvent.ACTION_DOWN) { |
| switch (event.getKeyCode()) { |
| case KeyEvent.KEYCODE_DPAD_UP: |
| if (!event.isAltPressed()) { |
| handled = arrowScroll(View.FOCUS_UP); |
| } else { |
| handled = fullScroll(View.FOCUS_UP); |
| } |
| break; |
| case KeyEvent.KEYCODE_DPAD_DOWN: |
| if (!event.isAltPressed()) { |
| handled = arrowScroll(View.FOCUS_DOWN); |
| } else { |
| handled = fullScroll(View.FOCUS_DOWN); |
| } |
| break; |
| case KeyEvent.KEYCODE_SPACE: |
| pageScroll(event.isShiftPressed() ? View.FOCUS_UP : View.FOCUS_DOWN); |
| break; |
| } |
| } |
| |
| return handled; |
| } |
| |
| private boolean inChild(int x, int y) { |
| if (getChildCount() > 0) { |
| final int scrollY = mScrollY; |
| final View child = getChildAt(0); |
| return !(y < child.getTop() - scrollY |
| || y >= child.getBottom() - scrollY |
| || x < child.getLeft() |
| || x >= child.getRight()); |
| } |
| return false; |
| } |
| |
| private void initOrResetVelocityTracker() { |
| if (mVelocityTracker == null) { |
| mVelocityTracker = VelocityTracker.obtain(); |
| } else { |
| mVelocityTracker.clear(); |
| } |
| } |
| |
| private void initVelocityTrackerIfNotExists() { |
| if (mVelocityTracker == null) { |
| mVelocityTracker = VelocityTracker.obtain(); |
| } |
| } |
| |
| private void recycleVelocityTracker() { |
| if (mVelocityTracker != null) { |
| mVelocityTracker.recycle(); |
| mVelocityTracker = null; |
| } |
| } |
| |
| @Override |
| public void requestDisallowInterceptTouchEvent(boolean disallowIntercept) { |
| if (disallowIntercept) { |
| recycleVelocityTracker(); |
| } |
| super.requestDisallowInterceptTouchEvent(disallowIntercept); |
| } |
| |
| |
| @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. |
| */ |
| |
| /* |
| * 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) && (mIsBeingDragged)) { |
| return true; |
| } |
| |
| if (super.onInterceptTouchEvent(ev)) { |
| return true; |
| } |
| |
| /* |
| * Don't try to intercept touch if we can't scroll anyway. |
| */ |
| if (getScrollY() == 0 && !canScrollVertically(1)) { |
| return false; |
| } |
| |
| 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. |
| */ |
| |
| /* |
| * 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 = ev.findPointerIndex(activePointerId); |
| if (pointerIndex == -1) { |
| Log.e(TAG, "Invalid pointerId=" + activePointerId |
| + " in onInterceptTouchEvent"); |
| break; |
| } |
| |
| final int y = (int) ev.getY(pointerIndex); |
| final int yDiff = Math.abs(y - mLastMotionY); |
| if (yDiff > mTouchSlop && (getNestedScrollAxes() & SCROLL_AXIS_VERTICAL) == 0) { |
| mIsBeingDragged = true; |
| mLastMotionY = y; |
| initVelocityTrackerIfNotExists(); |
| mVelocityTracker.addMovement(ev); |
| mNestedYOffset = 0; |
| if (mScrollStrictSpan == null) { |
| mScrollStrictSpan = StrictMode.enterCriticalSpan("ScrollView-scroll"); |
| } |
| final ViewParent parent = getParent(); |
| if (parent != null) { |
| parent.requestDisallowInterceptTouchEvent(true); |
| } |
| } |
| break; |
| } |
| |
| case MotionEvent.ACTION_DOWN: { |
| final int y = (int) ev.getY(); |
| if (!inChild((int) ev.getX(), (int) y)) { |
| mIsBeingDragged = false; |
| recycleVelocityTracker(); |
| break; |
| } |
| |
| /* |
| * Remember location of down touch. |
| * ACTION_DOWN always refers to pointer index 0. |
| */ |
| mLastMotionY = y; |
| mActivePointerId = ev.getPointerId(0); |
| |
| initOrResetVelocityTracker(); |
| mVelocityTracker.addMovement(ev); |
| /* |
| * If being flinged and user touches the screen, initiate drag; |
| * otherwise don't. mScroller.isFinished should be false when |
| * being flinged. We need to call computeScrollOffset() first so that |
| * isFinished() is correct. |
| */ |
| mScroller.computeScrollOffset(); |
| mIsBeingDragged = !mScroller.isFinished(); |
| if (mIsBeingDragged && mScrollStrictSpan == null) { |
| mScrollStrictSpan = StrictMode.enterCriticalSpan("ScrollView-scroll"); |
| } |
| startNestedScroll(SCROLL_AXIS_VERTICAL); |
| break; |
| } |
| |
| case MotionEvent.ACTION_CANCEL: |
| case MotionEvent.ACTION_UP: |
| /* Release the drag */ |
| mIsBeingDragged = false; |
| mActivePointerId = INVALID_POINTER; |
| recycleVelocityTracker(); |
| if (mScroller.springBack(mScrollX, mScrollY, 0, 0, 0, getScrollRange())) { |
| postInvalidateOnAnimation(); |
| } |
| stopNestedScroll(); |
| break; |
| case MotionEvent.ACTION_POINTER_UP: |
| onSecondaryPointerUp(ev); |
| break; |
| } |
| |
| /* |
| * The only time we want to intercept motion events is if we are in the |
| * drag mode. |
| */ |
| return mIsBeingDragged; |
| } |
| |
| private boolean shouldDisplayEdgeEffects() { |
| return getOverScrollMode() != OVER_SCROLL_NEVER; |
| } |
| |
| @Override |
| public boolean onTouchEvent(MotionEvent ev) { |
| initVelocityTrackerIfNotExists(); |
| |
| MotionEvent vtev = MotionEvent.obtain(ev); |
| |
| final int actionMasked = ev.getActionMasked(); |
| |
| if (actionMasked == MotionEvent.ACTION_DOWN) { |
| mNestedYOffset = 0; |
| } |
| vtev.offsetLocation(0, mNestedYOffset); |
| |
| switch (actionMasked) { |
| case MotionEvent.ACTION_DOWN: { |
| if (getChildCount() == 0) { |
| return false; |
| } |
| if ((mIsBeingDragged = !mScroller.isFinished())) { |
| final ViewParent parent = getParent(); |
| if (parent != null) { |
| parent.requestDisallowInterceptTouchEvent(true); |
| } |
| } |
| |
| /* |
| * If being flinged and user touches, stop the fling. isFinished |
| * will be false if being flinged. |
| */ |
| if (!mScroller.isFinished()) { |
| mScroller.abortAnimation(); |
| if (mFlingStrictSpan != null) { |
| mFlingStrictSpan.finish(); |
| mFlingStrictSpan = null; |
| } |
| } |
| |
| // Remember where the motion event started |
| mLastMotionY = (int) ev.getY(); |
| mActivePointerId = ev.getPointerId(0); |
| startNestedScroll(SCROLL_AXIS_VERTICAL); |
| break; |
| } |
| case MotionEvent.ACTION_MOVE: |
| final int activePointerIndex = ev.findPointerIndex(mActivePointerId); |
| if (activePointerIndex == -1) { |
| Log.e(TAG, "Invalid pointerId=" + mActivePointerId + " in onTouchEvent"); |
| break; |
| } |
| |
| final int y = (int) ev.getY(activePointerIndex); |
| int deltaY = mLastMotionY - y; |
| if (dispatchNestedPreScroll(0, deltaY, mScrollConsumed, mScrollOffset)) { |
| deltaY -= mScrollConsumed[1]; |
| vtev.offsetLocation(0, mScrollOffset[1]); |
| mNestedYOffset += mScrollOffset[1]; |
| } |
| if (!mIsBeingDragged && Math.abs(deltaY) > mTouchSlop) { |
| final ViewParent parent = getParent(); |
| if (parent != null) { |
| parent.requestDisallowInterceptTouchEvent(true); |
| } |
| mIsBeingDragged = true; |
| if (deltaY > 0) { |
| deltaY -= mTouchSlop; |
| } else { |
| deltaY += mTouchSlop; |
| } |
| } |
| if (mIsBeingDragged) { |
| // Scroll to follow the motion event |
| mLastMotionY = y - mScrollOffset[1]; |
| |
| final int oldY = mScrollY; |
| final int range = getScrollRange(); |
| final int overscrollMode = getOverScrollMode(); |
| boolean canOverscroll = overscrollMode == OVER_SCROLL_ALWAYS || |
| (overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && range > 0); |
| |
| // Calling overScrollBy will call onOverScrolled, which |
| // calls onScrollChanged if applicable. |
| if (overScrollBy(0, deltaY, 0, mScrollY, 0, range, 0, mOverscrollDistance, true) |
| && !hasNestedScrollingParent()) { |
| // Break our velocity if we hit a scroll barrier. |
| mVelocityTracker.clear(); |
| } |
| |
| final int scrolledDeltaY = mScrollY - oldY; |
| final int unconsumedY = deltaY - scrolledDeltaY; |
| if (dispatchNestedScroll(0, scrolledDeltaY, 0, unconsumedY, mScrollOffset)) { |
| mLastMotionY -= mScrollOffset[1]; |
| vtev.offsetLocation(0, mScrollOffset[1]); |
| mNestedYOffset += mScrollOffset[1]; |
| } else if (canOverscroll) { |
| final int pulledToY = oldY + deltaY; |
| if (pulledToY < 0) { |
| mEdgeGlowTop.onPull((float) deltaY / getHeight(), |
| ev.getX(activePointerIndex) / getWidth()); |
| if (!mEdgeGlowBottom.isFinished()) { |
| mEdgeGlowBottom.onRelease(); |
| } |
| } else if (pulledToY > range) { |
| mEdgeGlowBottom.onPull((float) deltaY / getHeight(), |
| 1.f - ev.getX(activePointerIndex) / getWidth()); |
| if (!mEdgeGlowTop.isFinished()) { |
| mEdgeGlowTop.onRelease(); |
| } |
| } |
| if (shouldDisplayEdgeEffects() |
| && (!mEdgeGlowTop.isFinished() || !mEdgeGlowBottom.isFinished())) { |
| postInvalidateOnAnimation(); |
| } |
| } |
| } |
| break; |
| case MotionEvent.ACTION_UP: |
| if (mIsBeingDragged) { |
| final VelocityTracker velocityTracker = mVelocityTracker; |
| velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); |
| int initialVelocity = (int) velocityTracker.getYVelocity(mActivePointerId); |
| |
| if ((Math.abs(initialVelocity) > mMinimumVelocity)) { |
| flingWithNestedDispatch(-initialVelocity); |
| } else if (mScroller.springBack(mScrollX, mScrollY, 0, 0, 0, |
| getScrollRange())) { |
| postInvalidateOnAnimation(); |
| } |
| |
| mActivePointerId = INVALID_POINTER; |
| endDrag(); |
| } |
| break; |
| case MotionEvent.ACTION_CANCEL: |
| if (mIsBeingDragged && getChildCount() > 0) { |
| if (mScroller.springBack(mScrollX, mScrollY, 0, 0, 0, getScrollRange())) { |
| postInvalidateOnAnimation(); |
| } |
| mActivePointerId = INVALID_POINTER; |
| endDrag(); |
| } |
| break; |
| case MotionEvent.ACTION_POINTER_DOWN: { |
| final int index = ev.getActionIndex(); |
| mLastMotionY = (int) ev.getY(index); |
| mActivePointerId = ev.getPointerId(index); |
| break; |
| } |
| case MotionEvent.ACTION_POINTER_UP: |
| onSecondaryPointerUp(ev); |
| mLastMotionY = (int) ev.getY(ev.findPointerIndex(mActivePointerId)); |
| break; |
| } |
| |
| if (mVelocityTracker != null) { |
| mVelocityTracker.addMovement(vtev); |
| } |
| vtev.recycle(); |
| return true; |
| } |
| |
| 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; |
| mLastMotionY = (int) ev.getY(newPointerIndex); |
| mActivePointerId = ev.getPointerId(newPointerIndex); |
| if (mVelocityTracker != null) { |
| mVelocityTracker.clear(); |
| } |
| } |
| } |
| |
| @Override |
| public boolean onGenericMotionEvent(MotionEvent event) { |
| switch (event.getAction()) { |
| case MotionEvent.ACTION_SCROLL: |
| final float axisValue; |
| if (event.isFromSource(InputDevice.SOURCE_CLASS_POINTER)) { |
| axisValue = event.getAxisValue(MotionEvent.AXIS_VSCROLL); |
| } else if (event.isFromSource(InputDevice.SOURCE_ROTARY_ENCODER)) { |
| axisValue = event.getAxisValue(MotionEvent.AXIS_SCROLL); |
| } else { |
| axisValue = 0; |
| } |
| |
| final int delta = Math.round(axisValue * mVerticalScrollFactor); |
| if (delta != 0) { |
| final int range = getScrollRange(); |
| int oldScrollY = mScrollY; |
| int newScrollY = oldScrollY - delta; |
| if (newScrollY < 0) { |
| newScrollY = 0; |
| } else if (newScrollY > range) { |
| newScrollY = range; |
| } |
| if (newScrollY != oldScrollY) { |
| super.scrollTo(mScrollX, newScrollY); |
| return true; |
| } |
| } |
| break; |
| } |
| |
| return super.onGenericMotionEvent(event); |
| } |
| |
| @Override |
| protected void onOverScrolled(int scrollX, int scrollY, |
| boolean clampedX, boolean clampedY) { |
| // Treat animating scrolls differently; see #computeScroll() for why. |
| if (!mScroller.isFinished()) { |
| final int oldX = mScrollX; |
| final int oldY = mScrollY; |
| mScrollX = scrollX; |
| mScrollY = scrollY; |
| invalidateParentIfNeeded(); |
| onScrollChanged(mScrollX, mScrollY, oldX, oldY); |
| if (clampedY) { |
| mScroller.springBack(mScrollX, mScrollY, 0, 0, 0, getScrollRange()); |
| } |
| } else { |
| super.scrollTo(scrollX, scrollY); |
| } |
| |
| awakenScrollBars(); |
| } |
| |
| /** @hide */ |
| @Override |
| public boolean performAccessibilityActionInternal(int action, Bundle arguments) { |
| if (super.performAccessibilityActionInternal(action, arguments)) { |
| return true; |
| } |
| if (!isEnabled()) { |
| return false; |
| } |
| switch (action) { |
| case AccessibilityNodeInfo.ACTION_SCROLL_FORWARD: |
| case R.id.accessibilityActionScrollDown: { |
| final int viewportHeight = getHeight() - mPaddingBottom - mPaddingTop; |
| final int targetScrollY = Math.min(mScrollY + viewportHeight, getScrollRange()); |
| if (targetScrollY != mScrollY) { |
| smoothScrollTo(0, targetScrollY); |
| return true; |
| } |
| } return false; |
| case AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD: |
| case R.id.accessibilityActionScrollUp: { |
| final int viewportHeight = getHeight() - mPaddingBottom - mPaddingTop; |
| final int targetScrollY = Math.max(mScrollY - viewportHeight, 0); |
| if (targetScrollY != mScrollY) { |
| smoothScrollTo(0, targetScrollY); |
| return true; |
| } |
| } return false; |
| } |
| return false; |
| } |
| |
| @Override |
| public CharSequence getAccessibilityClassName() { |
| return ScrollView.class.getName(); |
| } |
| |
| /** @hide */ |
| @Override |
| public void onInitializeAccessibilityNodeInfoInternal(AccessibilityNodeInfo info) { |
| super.onInitializeAccessibilityNodeInfoInternal(info); |
| if (isEnabled()) { |
| final int scrollRange = getScrollRange(); |
| if (scrollRange > 0) { |
| info.setScrollable(true); |
| if (mScrollY > 0) { |
| info.addAction( |
| AccessibilityNodeInfo.AccessibilityAction.ACTION_SCROLL_BACKWARD); |
| info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_SCROLL_UP); |
| } |
| if (mScrollY < scrollRange) { |
| info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_SCROLL_FORWARD); |
| info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_SCROLL_DOWN); |
| } |
| } |
| } |
| } |
| |
| /** @hide */ |
| @Override |
| public void onInitializeAccessibilityEventInternal(AccessibilityEvent event) { |
| super.onInitializeAccessibilityEventInternal(event); |
| final boolean scrollable = getScrollRange() > 0; |
| event.setScrollable(scrollable); |
| event.setMaxScrollX(mScrollX); |
| event.setMaxScrollY(getScrollRange()); |
| } |
| |
| private int getScrollRange() { |
| int scrollRange = 0; |
| if (getChildCount() > 0) { |
| View child = getChildAt(0); |
| scrollRange = Math.max(0, |
| child.getHeight() - (getHeight() - mPaddingBottom - mPaddingTop)); |
| } |
| return scrollRange; |
| } |
| |
| /** |
| * <p> |
| * Finds the next focusable component that fits in the specified bounds. |
| * </p> |
| * |
| * @param topFocus look for a candidate is the one at the top of the bounds |
| * if topFocus is true, or at the bottom of the bounds if topFocus is |
| * false |
| * @param top the top offset of the bounds in which a focusable must be |
| * found |
| * @param bottom the bottom offset of the bounds in which a focusable must |
| * be found |
| * @return the next focusable component in the bounds or null if none can |
| * be found |
| */ |
| private View findFocusableViewInBounds(boolean topFocus, int top, int bottom) { |
| |
| List<View> focusables = getFocusables(View.FOCUS_FORWARD); |
| View focusCandidate = null; |
| |
| /* |
| * A fully contained focusable is one where its top is below the bound's |
| * top, and its bottom is above the bound's bottom. A partially |
| * contained focusable is one where some part of it is within the |
| * bounds, but it also has some part that is not within bounds. A fully contained |
| * focusable is preferred to a partially contained focusable. |
| */ |
| boolean foundFullyContainedFocusable = false; |
| |
| int count = focusables.size(); |
| for (int i = 0; i < count; i++) { |
| View view = focusables.get(i); |
| int viewTop = view.getTop(); |
| int viewBottom = view.getBottom(); |
| |
| if (top < viewBottom && viewTop < bottom) { |
| /* |
| * the focusable is in the target area, it is a candidate for |
| * focusing |
| */ |
| |
| final boolean viewIsFullyContained = (top < viewTop) && |
| (viewBottom < bottom); |
| |
| if (focusCandidate == null) { |
| /* No candidate, take this one */ |
| focusCandidate = view; |
| foundFullyContainedFocusable = viewIsFullyContained; |
| } else { |
| final boolean viewIsCloserToBoundary = |
| (topFocus && viewTop < focusCandidate.getTop()) || |
| (!topFocus && viewBottom > focusCandidate |
| .getBottom()); |
| |
| if (foundFullyContainedFocusable) { |
| if (viewIsFullyContained && viewIsCloserToBoundary) { |
| /* |
| * We're dealing with only fully contained views, so |
| * it has to be closer to the boundary to beat our |
| * candidate |
| */ |
| focusCandidate = view; |
| } |
| } else { |
| if (viewIsFullyContained) { |
| /* Any fully contained view beats a partially contained view */ |
| focusCandidate = view; |
| foundFullyContainedFocusable = true; |
| } else if (viewIsCloserToBoundary) { |
| /* |
| * Partially contained view beats another partially |
| * contained view if it's closer |
| */ |
| focusCandidate = view; |
| } |
| } |
| } |
| } |
| } |
| |
| return focusCandidate; |
| } |
| |
| /** |
| * <p>Handles scrolling in response to a "page up/down" shortcut press. This |
| * method will scroll the view by one page up or down and give the focus |
| * to the topmost/bottommost component in the new visible area. If no |
| * component is a good candidate for focus, this scrollview reclaims the |
| * focus.</p> |
| * |
| * @param direction the scroll direction: {@link android.view.View#FOCUS_UP} |
| * to go one page up or |
| * {@link android.view.View#FOCUS_DOWN} to go one page down |
| * @return true if the key event is consumed by this method, false otherwise |
| */ |
| public boolean pageScroll(int direction) { |
| boolean down = direction == View.FOCUS_DOWN; |
| int height = getHeight(); |
| |
| if (down) { |
| mTempRect.top = getScrollY() + height; |
| int count = getChildCount(); |
| if (count > 0) { |
| View view = getChildAt(count - 1); |
| if (mTempRect.top + height > view.getBottom()) { |
| mTempRect.top = view.getBottom() - height; |
| } |
| } |
| } else { |
| mTempRect.top = getScrollY() - height; |
| if (mTempRect.top < 0) { |
| mTempRect.top = 0; |
| } |
| } |
| mTempRect.bottom = mTempRect.top + height; |
| |
| return scrollAndFocus(direction, mTempRect.top, mTempRect.bottom); |
| } |
| |
| /** |
| * <p>Handles scrolling in response to a "home/end" shortcut press. This |
| * method will scroll the view to the top or bottom and give the focus |
| * to the topmost/bottommost component in the new visible area. If no |
| * component is a good candidate for focus, this scrollview reclaims the |
| * focus.</p> |
| * |
| * @param direction the scroll direction: {@link android.view.View#FOCUS_UP} |
| * to go the top of the view or |
| * {@link android.view.View#FOCUS_DOWN} to go the bottom |
| * @return true if the key event is consumed by this method, false otherwise |
| */ |
| public boolean fullScroll(int direction) { |
| boolean down = direction == View.FOCUS_DOWN; |
| int height = getHeight(); |
| |
| mTempRect.top = 0; |
| mTempRect.bottom = height; |
| |
| if (down) { |
| int count = getChildCount(); |
| if (count > 0) { |
| View view = getChildAt(count - 1); |
| mTempRect.bottom = view.getBottom() + mPaddingBottom; |
| mTempRect.top = mTempRect.bottom - height; |
| } |
| } |
| |
| return scrollAndFocus(direction, mTempRect.top, mTempRect.bottom); |
| } |
| |
| /** |
| * <p>Scrolls the view to make the area defined by <code>top</code> and |
| * <code>bottom</code> visible. This method attempts to give the focus |
| * to a component visible in this area. If no component can be focused in |
| * the new visible area, the focus is reclaimed by this ScrollView.</p> |
| * |
| * @param direction the scroll direction: {@link android.view.View#FOCUS_UP} |
| * to go upward, {@link android.view.View#FOCUS_DOWN} to downward |
| * @param top the top offset of the new area to be made visible |
| * @param bottom the bottom offset of the new area to be made visible |
| * @return true if the key event is consumed by this method, false otherwise |
| */ |
| private boolean scrollAndFocus(int direction, int top, int bottom) { |
| boolean handled = true; |
| |
| int height = getHeight(); |
| int containerTop = getScrollY(); |
| int containerBottom = containerTop + height; |
| boolean up = direction == View.FOCUS_UP; |
| |
| View newFocused = findFocusableViewInBounds(up, top, bottom); |
| if (newFocused == null) { |
| newFocused = this; |
| } |
| |
| if (top >= containerTop && bottom <= containerBottom) { |
| handled = false; |
| } else { |
| int delta = up ? (top - containerTop) : (bottom - containerBottom); |
| doScrollY(delta); |
| } |
| |
| if (newFocused != findFocus()) newFocused.requestFocus(direction); |
| |
| return handled; |
| } |
| |
| /** |
| * Handle scrolling in response to an up or down arrow click. |
| * |
| * @param direction The direction corresponding to the arrow key that was |
| * pressed |
| * @return True if we consumed the event, false otherwise |
| */ |
| public boolean arrowScroll(int direction) { |
| |
| View currentFocused = findFocus(); |
| if (currentFocused == this) currentFocused = null; |
| |
| View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused, direction); |
| |
| final int maxJump = getMaxScrollAmount(); |
| |
| if (nextFocused != null && isWithinDeltaOfScreen(nextFocused, maxJump, getHeight())) { |
| nextFocused.getDrawingRect(mTempRect); |
| offsetDescendantRectToMyCoords(nextFocused, mTempRect); |
| int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect); |
| doScrollY(scrollDelta); |
| nextFocused.requestFocus(direction); |
| } else { |
| // no new focus |
| int scrollDelta = maxJump; |
| |
| if (direction == View.FOCUS_UP && getScrollY() < scrollDelta) { |
| scrollDelta = getScrollY(); |
| } else if (direction == View.FOCUS_DOWN) { |
| if (getChildCount() > 0) { |
| int daBottom = getChildAt(0).getBottom(); |
| int screenBottom = getScrollY() + getHeight() - mPaddingBottom; |
| if (daBottom - screenBottom < maxJump) { |
| scrollDelta = daBottom - screenBottom; |
| } |
| } |
| } |
| if (scrollDelta == 0) { |
| return false; |
| } |
| doScrollY(direction == View.FOCUS_DOWN ? scrollDelta : -scrollDelta); |
| } |
| |
| if (currentFocused != null && currentFocused.isFocused() |
| && isOffScreen(currentFocused)) { |
| // previously focused item still has focus and is off screen, give |
| // it up (take it back to ourselves) |
| // (also, need to temporarily force FOCUS_BEFORE_DESCENDANTS so we are |
| // sure to |
| // get it) |
| final int descendantFocusability = getDescendantFocusability(); // save |
| setDescendantFocusability(ViewGroup.FOCUS_BEFORE_DESCENDANTS); |
| requestFocus(); |
| setDescendantFocusability(descendantFocusability); // restore |
| } |
| return true; |
| } |
| |
| /** |
| * @return whether the descendant of this scroll view is scrolled off |
| * screen. |
| */ |
| private boolean isOffScreen(View descendant) { |
| return !isWithinDeltaOfScreen(descendant, 0, getHeight()); |
| } |
| |
| /** |
| * @return whether the descendant of this scroll view is within delta |
| * pixels of being on the screen. |
| */ |
| private boolean isWithinDeltaOfScreen(View descendant, int delta, int height) { |
| descendant.getDrawingRect(mTempRect); |
| offsetDescendantRectToMyCoords(descendant, mTempRect); |
| |
| return (mTempRect.bottom + delta) >= getScrollY() |
| && (mTempRect.top - delta) <= (getScrollY() + height); |
| } |
| |
| /** |
| * Smooth scroll by a Y delta |
| * |
| * @param delta the number of pixels to scroll by on the Y axis |
| */ |
| private void doScrollY(int delta) { |
| if (delta != 0) { |
| if (mSmoothScrollingEnabled) { |
| smoothScrollBy(0, delta); |
| } else { |
| scrollBy(0, delta); |
| } |
| } |
| } |
| |
| /** |
| * Like {@link View#scrollBy}, but scroll smoothly instead of immediately. |
| * |
| * @param dx the number of pixels to scroll by on the X axis |
| * @param dy the number of pixels to scroll by on the Y axis |
| */ |
| public final void smoothScrollBy(int dx, int dy) { |
| if (getChildCount() == 0) { |
| // Nothing to do. |
| return; |
| } |
| long duration = AnimationUtils.currentAnimationTimeMillis() - mLastScroll; |
| if (duration > ANIMATED_SCROLL_GAP) { |
| final int height = getHeight() - mPaddingBottom - mPaddingTop; |
| final int bottom = getChildAt(0).getHeight(); |
| final int maxY = Math.max(0, bottom - height); |
| final int scrollY = mScrollY; |
| dy = Math.max(0, Math.min(scrollY + dy, maxY)) - scrollY; |
| |
| mScroller.startScroll(mScrollX, scrollY, 0, dy); |
| postInvalidateOnAnimation(); |
| } else { |
| if (!mScroller.isFinished()) { |
| mScroller.abortAnimation(); |
| if (mFlingStrictSpan != null) { |
| mFlingStrictSpan.finish(); |
| mFlingStrictSpan = null; |
| } |
| } |
| scrollBy(dx, dy); |
| } |
| mLastScroll = AnimationUtils.currentAnimationTimeMillis(); |
| } |
| |
| /** |
| * Like {@link #scrollTo}, but scroll smoothly instead of immediately. |
| * |
| * @param x the position where to scroll on the X axis |
| * @param y the position where to scroll on the Y axis |
| */ |
| public final void smoothScrollTo(int x, int y) { |
| smoothScrollBy(x - mScrollX, y - mScrollY); |
| } |
| |
| /** |
| * <p>The scroll range of a scroll view is the overall height of all of its |
| * children.</p> |
| */ |
| @Override |
| protected int computeVerticalScrollRange() { |
| final int count = getChildCount(); |
| final int contentHeight = getHeight() - mPaddingBottom - mPaddingTop; |
| if (count == 0) { |
| return contentHeight; |
| } |
| |
| int scrollRange = getChildAt(0).getBottom(); |
| final int scrollY = mScrollY; |
| final int overscrollBottom = Math.max(0, scrollRange - contentHeight); |
| if (scrollY < 0) { |
| scrollRange -= scrollY; |
| } else if (scrollY > overscrollBottom) { |
| scrollRange += scrollY - overscrollBottom; |
| } |
| |
| return scrollRange; |
| } |
| |
| @Override |
| protected int computeVerticalScrollOffset() { |
| return Math.max(0, super.computeVerticalScrollOffset()); |
| } |
| |
| @Override |
| protected void measureChild(View child, int parentWidthMeasureSpec, |
| int parentHeightMeasureSpec) { |
| ViewGroup.LayoutParams lp = child.getLayoutParams(); |
| |
| int childWidthMeasureSpec; |
| int childHeightMeasureSpec; |
| |
| childWidthMeasureSpec = getChildMeasureSpec(parentWidthMeasureSpec, mPaddingLeft |
| + mPaddingRight, lp.width); |
| final int verticalPadding = mPaddingTop + mPaddingBottom; |
| childHeightMeasureSpec = MeasureSpec.makeSafeMeasureSpec( |
| Math.max(0, MeasureSpec.getSize(parentHeightMeasureSpec) - verticalPadding), |
| MeasureSpec.UNSPECIFIED); |
| |
| child.measure(childWidthMeasureSpec, childHeightMeasureSpec); |
| } |
| |
| @Override |
| protected void measureChildWithMargins(View child, int parentWidthMeasureSpec, int widthUsed, |
| int parentHeightMeasureSpec, int heightUsed) { |
| final MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams(); |
| |
| final int childWidthMeasureSpec = getChildMeasureSpec(parentWidthMeasureSpec, |
| mPaddingLeft + mPaddingRight + lp.leftMargin + lp.rightMargin |
| + widthUsed, lp.width); |
| final int usedTotal = mPaddingTop + mPaddingBottom + lp.topMargin + lp.bottomMargin + |
| heightUsed; |
| final int childHeightMeasureSpec = MeasureSpec.makeSafeMeasureSpec( |
| Math.max(0, MeasureSpec.getSize(parentHeightMeasureSpec) - usedTotal), |
| MeasureSpec.UNSPECIFIED); |
| |
| child.measure(childWidthMeasureSpec, childHeightMeasureSpec); |
| } |
| |
| @Override |
| public void computeScroll() { |
| if (mScroller.computeScrollOffset()) { |
| // This is called at drawing time by ViewGroup. We don't want to |
| // re-show the scrollbars at this point, which scrollTo will do, |
| // so we replicate most of scrollTo here. |
| // |
| // It's a little odd to call onScrollChanged from inside the drawing. |
| // |
| // It is, except when you remember that computeScroll() is used to |
| // animate scrolling. So unless we want to defer the onScrollChanged() |
| // until the end of the animated scrolling, we don't really have a |
| // choice here. |
| // |
| // I agree. The alternative, which I think would be worse, is to post |
| // something and tell the subclasses later. This is bad because there |
| // will be a window where mScrollX/Y is different from what the app |
| // thinks it is. |
| // |
| int oldX = mScrollX; |
| int oldY = mScrollY; |
| int x = mScroller.getCurrX(); |
| int y = mScroller.getCurrY(); |
| |
| if (oldX != x || oldY != y) { |
| final int range = getScrollRange(); |
| final int overscrollMode = getOverScrollMode(); |
| final boolean canOverscroll = overscrollMode == OVER_SCROLL_ALWAYS || |
| (overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && range > 0); |
| |
| overScrollBy(x - oldX, y - oldY, oldX, oldY, 0, range, |
| 0, mOverflingDistance, false); |
| onScrollChanged(mScrollX, mScrollY, oldX, oldY); |
| |
| if (canOverscroll) { |
| if (y < 0 && oldY >= 0) { |
| mEdgeGlowTop.onAbsorb((int) mScroller.getCurrVelocity()); |
| } else if (y > range && oldY <= range) { |
| mEdgeGlowBottom.onAbsorb((int) mScroller.getCurrVelocity()); |
| } |
| } |
| } |
| |
| if (!awakenScrollBars()) { |
| // Keep on drawing until the animation has finished. |
| postInvalidateOnAnimation(); |
| } |
| } else { |
| if (mFlingStrictSpan != null) { |
| mFlingStrictSpan.finish(); |
| mFlingStrictSpan = null; |
| } |
| } |
| } |
| |
| /** |
| * Scrolls the view to the given child. |
| * |
| * @param child the View to scroll to |
| */ |
| public void scrollToDescendant(@NonNull View child) { |
| if (!mIsLayoutDirty) { |
| child.getDrawingRect(mTempRect); |
| |
| /* Offset from child's local coordinates to ScrollView coordinates */ |
| offsetDescendantRectToMyCoords(child, mTempRect); |
| |
| int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect); |
| |
| if (scrollDelta != 0) { |
| scrollBy(0, scrollDelta); |
| } |
| } else { |
| mChildToScrollTo = child; |
| } |
| } |
| |
| /** |
| * If rect is off screen, scroll just enough to get it (or at least the |
| * first screen size chunk of it) on screen. |
| * |
| * @param rect The rectangle. |
| * @param immediate True to scroll immediately without animation |
| * @return true if scrolling was performed |
| */ |
| private boolean scrollToChildRect(Rect rect, boolean immediate) { |
| final int delta = computeScrollDeltaToGetChildRectOnScreen(rect); |
| final boolean scroll = delta != 0; |
| if (scroll) { |
| if (immediate) { |
| scrollBy(0, delta); |
| } else { |
| smoothScrollBy(0, delta); |
| } |
| } |
| return scroll; |
| } |
| |
| /** |
| * Compute the amount to scroll in the Y direction in order to get |
| * a rectangle completely on the screen (or, if taller than the screen, |
| * at least the first screen size chunk of it). |
| * |
| * @param rect The rect. |
| * @return The scroll delta. |
| */ |
| protected int computeScrollDeltaToGetChildRectOnScreen(Rect rect) { |
| if (getChildCount() == 0) return 0; |
| |
| int height = getHeight(); |
| int screenTop = getScrollY(); |
| int screenBottom = screenTop + height; |
| |
| int fadingEdge = getVerticalFadingEdgeLength(); |
| |
| // leave room for top fading edge as long as rect isn't at very top |
| if (rect.top > 0) { |
| screenTop += fadingEdge; |
| } |
| |
| // leave room for bottom fading edge as long as rect isn't at very bottom |
| if (rect.bottom < getChildAt(0).getHeight()) { |
| screenBottom -= fadingEdge; |
| } |
| |
| int scrollYDelta = 0; |
| |
| if (rect.bottom > screenBottom && rect.top > screenTop) { |
| // need to move down to get it in view: move down just enough so |
| // that the entire rectangle is in view (or at least the first |
| // screen size chunk). |
| |
| if (rect.height() > height) { |
| // just enough to get screen size chunk on |
| scrollYDelta += (rect.top - screenTop); |
| } else { |
| // get entire rect at bottom of screen |
| scrollYDelta += (rect.bottom - screenBottom); |
| } |
| |
| // make sure we aren't scrolling beyond the end of our content |
| int bottom = getChildAt(0).getBottom(); |
| int distanceToBottom = bottom - screenBottom; |
| scrollYDelta = Math.min(scrollYDelta, distanceToBottom); |
| |
| } else if (rect.top < screenTop && rect.bottom < screenBottom) { |
| // need to move up to get it in view: move up just enough so that |
| // entire rectangle is in view (or at least the first screen |
| // size chunk of it). |
| |
| if (rect.height() > height) { |
| // screen size chunk |
| scrollYDelta -= (screenBottom - rect.bottom); |
| } else { |
| // entire rect at top |
| scrollYDelta -= (screenTop - rect.top); |
| } |
| |
| // make sure we aren't scrolling any further than the top our content |
| scrollYDelta = Math.max(scrollYDelta, -getScrollY()); |
| } |
| return scrollYDelta; |
| } |
| |
| @Override |
| public void requestChildFocus(View child, View focused) { |
| if (focused != null && focused.getRevealOnFocusHint()) { |
| if (!mIsLayoutDirty) { |
| scrollToDescendant(focused); |
| } else { |
| // The child may not be laid out yet, we can't compute the scroll yet |
| mChildToScrollTo = focused; |
| } |
| } |
| super.requestChildFocus(child, focused); |
| } |
| |
| |
| /** |
| * When looking for focus in children of a scroll view, need to be a little |
| * more careful not to give focus to something that is scrolled off screen. |
| * |
| * This is more expensive than the default {@link android.view.ViewGroup} |
| * implementation, otherwise this behavior might have been made the default. |
| */ |
| @Override |
| protected boolean onRequestFocusInDescendants(int direction, |
| Rect previouslyFocusedRect) { |
| |
| // convert from forward / backward notation to up / down / left / right |
| // (ugh). |
| if (direction == View.FOCUS_FORWARD) { |
| direction = View.FOCUS_DOWN; |
| } else if (direction == View.FOCUS_BACKWARD) { |
| direction = View.FOCUS_UP; |
| } |
| |
| final View nextFocus = previouslyFocusedRect == null ? |
| FocusFinder.getInstance().findNextFocus(this, null, direction) : |
| FocusFinder.getInstance().findNextFocusFromRect(this, |
| previouslyFocusedRect, direction); |
| |
| if (nextFocus == null) { |
| return false; |
| } |
| |
| if (isOffScreen(nextFocus)) { |
| return false; |
| } |
| |
| return nextFocus.requestFocus(direction, previouslyFocusedRect); |
| } |
| |
| @Override |
| public boolean requestChildRectangleOnScreen(View child, Rect rectangle, |
| boolean immediate) { |
| // offset into coordinate space of this scroll view |
| rectangle.offset(child.getLeft() - child.getScrollX(), |
| child.getTop() - child.getScrollY()); |
| |
| return scrollToChildRect(rectangle, immediate); |
| } |
| |
| @Override |
| public void requestLayout() { |
| mIsLayoutDirty = true; |
| super.requestLayout(); |
| } |
| |
| @Override |
| protected void onDetachedFromWindow() { |
| super.onDetachedFromWindow(); |
| |
| if (mScrollStrictSpan != null) { |
| mScrollStrictSpan.finish(); |
| mScrollStrictSpan = null; |
| } |
| if (mFlingStrictSpan != null) { |
| mFlingStrictSpan.finish(); |
| mFlingStrictSpan = null; |
| } |
| } |
| |
| @Override |
| protected void onLayout(boolean changed, int l, int t, int r, int b) { |
| super.onLayout(changed, l, t, r, b); |
| mIsLayoutDirty = false; |
| // Give a child focus if it needs it |
| if (mChildToScrollTo != null && isViewDescendantOf(mChildToScrollTo, this)) { |
| scrollToDescendant(mChildToScrollTo); |
| } |
| mChildToScrollTo = null; |
| |
| if (!isLaidOut()) { |
| if (mSavedState != null) { |
| mScrollY = mSavedState.scrollPosition; |
| mSavedState = null; |
| } // mScrollY default value is "0" |
| |
| final int childHeight = (getChildCount() > 0) ? getChildAt(0).getMeasuredHeight() : 0; |
| final int scrollRange = Math.max(0, |
| childHeight - (b - t - mPaddingBottom - mPaddingTop)); |
| |
| // Don't forget to clamp |
| if (mScrollY > scrollRange) { |
| mScrollY = scrollRange; |
| } else if (mScrollY < 0) { |
| mScrollY = 0; |
| } |
| } |
| |
| // Calling this with the present values causes it to re-claim them |
| scrollTo(mScrollX, mScrollY); |
| } |
| |
| @Override |
| protected void onSizeChanged(int w, int h, int oldw, int oldh) { |
| super.onSizeChanged(w, h, oldw, oldh); |
| |
| View currentFocused = findFocus(); |
| if (null == currentFocused || this == currentFocused) |
| return; |
| |
| // If the currently-focused view was visible on the screen when the |
| // screen was at the old height, then scroll the screen to make that |
| // view visible with the new screen height. |
| if (isWithinDeltaOfScreen(currentFocused, 0, oldh)) { |
| currentFocused.getDrawingRect(mTempRect); |
| offsetDescendantRectToMyCoords(currentFocused, mTempRect); |
| int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect); |
| doScrollY(scrollDelta); |
| } |
| } |
| |
| /** |
| * Return true if child is a descendant of parent, (or equal to the parent). |
| */ |
| private static boolean isViewDescendantOf(View child, View parent) { |
| if (child == parent) { |
| return true; |
| } |
| |
| final ViewParent theParent = child.getParent(); |
| return (theParent instanceof ViewGroup) && isViewDescendantOf((View) theParent, parent); |
| } |
| |
| /** |
| * Fling the scroll view |
| * |
| * @param velocityY The initial velocity in the Y direction. Positive |
| * numbers mean that the finger/cursor is moving down the screen, |
| * which means we want to scroll towards the top. |
| */ |
| public void fling(int velocityY) { |
| if (getChildCount() > 0) { |
| int height = getHeight() - mPaddingBottom - mPaddingTop; |
| int bottom = getChildAt(0).getHeight(); |
| |
| mScroller.fling(mScrollX, mScrollY, 0, velocityY, 0, 0, 0, |
| Math.max(0, bottom - height), 0, height/2); |
| |
| if (mFlingStrictSpan == null) { |
| mFlingStrictSpan = StrictMode.enterCriticalSpan("ScrollView-fling"); |
| } |
| |
| postInvalidateOnAnimation(); |
| } |
| } |
| |
| private void flingWithNestedDispatch(int velocityY) { |
| final boolean canFling = (mScrollY > 0 || velocityY > 0) && |
| (mScrollY < getScrollRange() || velocityY < 0); |
| if (!dispatchNestedPreFling(0, velocityY)) { |
| dispatchNestedFling(0, velocityY, canFling); |
| if (canFling) { |
| fling(velocityY); |
| } |
| } |
| } |
| |
| @UnsupportedAppUsage |
| private void endDrag() { |
| mIsBeingDragged = false; |
| |
| recycleVelocityTracker(); |
| |
| if (shouldDisplayEdgeEffects()) { |
| mEdgeGlowTop.onRelease(); |
| mEdgeGlowBottom.onRelease(); |
| } |
| |
| if (mScrollStrictSpan != null) { |
| mScrollStrictSpan.finish(); |
| mScrollStrictSpan = null; |
| } |
| } |
| |
| /** |
| * {@inheritDoc} |
| * |
| * <p>This version also clamps the scrolling to the bounds of our child. |
| */ |
| @Override |
| public void scrollTo(int x, int y) { |
| // we rely on the fact the View.scrollBy calls scrollTo. |
| if (getChildCount() > 0) { |
| View child = getChildAt(0); |
| x = clamp(x, getWidth() - mPaddingRight - mPaddingLeft, child.getWidth()); |
| y = clamp(y, getHeight() - mPaddingBottom - mPaddingTop, child.getHeight()); |
| if (x != mScrollX || y != mScrollY) { |
| super.scrollTo(x, y); |
| } |
| } |
| } |
| |
| @Override |
| public boolean onStartNestedScroll(View child, View target, int nestedScrollAxes) { |
| return (nestedScrollAxes & SCROLL_AXIS_VERTICAL) != 0; |
| } |
| |
| @Override |
| public void onNestedScrollAccepted(View child, View target, int axes) { |
| super.onNestedScrollAccepted(child, target, axes); |
| startNestedScroll(SCROLL_AXIS_VERTICAL); |
| } |
| |
| /** |
| * @inheritDoc |
| */ |
| @Override |
| public void onStopNestedScroll(View target) { |
| super.onStopNestedScroll(target); |
| } |
| |
| @Override |
| public void onNestedScroll(View target, int dxConsumed, int dyConsumed, |
| int dxUnconsumed, int dyUnconsumed) { |
| final int oldScrollY = mScrollY; |
| scrollBy(0, dyUnconsumed); |
| final int myConsumed = mScrollY - oldScrollY; |
| final int myUnconsumed = dyUnconsumed - myConsumed; |
| dispatchNestedScroll(0, myConsumed, 0, myUnconsumed, null); |
| } |
| |
| /** |
| * @inheritDoc |
| */ |
| @Override |
| public boolean onNestedFling(View target, float velocityX, float velocityY, boolean consumed) { |
| if (!consumed) { |
| flingWithNestedDispatch((int) velocityY); |
| return true; |
| } |
| return false; |
| } |
| |
| @Override |
| public void draw(Canvas canvas) { |
| super.draw(canvas); |
| if (shouldDisplayEdgeEffects()) { |
| final int scrollY = mScrollY; |
| final boolean clipToPadding = getClipToPadding(); |
| if (!mEdgeGlowTop.isFinished()) { |
| final int restoreCount = canvas.save(); |
| final int width; |
| final int height; |
| final float translateX; |
| final float translateY; |
| if (clipToPadding) { |
| width = getWidth() - mPaddingLeft - mPaddingRight; |
| height = getHeight() - mPaddingTop - mPaddingBottom; |
| translateX = mPaddingLeft; |
| translateY = mPaddingTop; |
| } else { |
| width = getWidth(); |
| height = getHeight(); |
| translateX = 0; |
| translateY = 0; |
| } |
| canvas.translate(translateX, Math.min(0, scrollY) + translateY); |
| mEdgeGlowTop.setSize(width, height); |
| if (mEdgeGlowTop.draw(canvas)) { |
| postInvalidateOnAnimation(); |
| } |
| canvas.restoreToCount(restoreCount); |
| } |
| if (!mEdgeGlowBottom.isFinished()) { |
| final int restoreCount = canvas.save(); |
| final int width; |
| final int height; |
| final float translateX; |
| final float translateY; |
| if (clipToPadding) { |
| width = getWidth() - mPaddingLeft - mPaddingRight; |
| height = getHeight() - mPaddingTop - mPaddingBottom; |
| translateX = mPaddingLeft; |
| translateY = mPaddingTop; |
| } else { |
| width = getWidth(); |
| height = getHeight(); |
| translateX = 0; |
| translateY = 0; |
| } |
| canvas.translate(-width + translateX, |
| Math.max(getScrollRange(), scrollY) + height + translateY); |
| canvas.rotate(180, width, 0); |
| mEdgeGlowBottom.setSize(width, height); |
| if (mEdgeGlowBottom.draw(canvas)) { |
| postInvalidateOnAnimation(); |
| } |
| canvas.restoreToCount(restoreCount); |
| } |
| } |
| } |
| |
| private static int clamp(int n, int my, int child) { |
| if (my >= child || n < 0) { |
| /* my >= child is this case: |
| * |--------------- me ---------------| |
| * |------ child ------| |
| * or |
| * |--------------- me ---------------| |
| * |------ child ------| |
| * or |
| * |--------------- me ---------------| |
| * |------ child ------| |
| * |
| * n < 0 is this case: |
| * |------ me ------| |
| * |-------- child --------| |
| * |-- mScrollX --| |
| */ |
| return 0; |
| } |
| if ((my+n) > child) { |
| /* this case: |
| * |------ me ------| |
| * |------ child ------| |
| * |-- mScrollX --| |
| */ |
| return child-my; |
| } |
| return n; |
| } |
| |
| @Override |
| protected void onRestoreInstanceState(Parcelable state) { |
| if (mContext.getApplicationInfo().targetSdkVersion <= Build.VERSION_CODES.JELLY_BEAN_MR2) { |
| // Some old apps reused IDs in ways they shouldn't have. |
| // Don't break them, but they don't get scroll state restoration. |
| super.onRestoreInstanceState(state); |
| return; |
| } |
| SavedState ss = (SavedState) state; |
| super.onRestoreInstanceState(ss.getSuperState()); |
| mSavedState = ss; |
| requestLayout(); |
| } |
| |
| @Override |
| protected Parcelable onSaveInstanceState() { |
| if (mContext.getApplicationInfo().targetSdkVersion <= Build.VERSION_CODES.JELLY_BEAN_MR2) { |
| // Some old apps reused IDs in ways they shouldn't have. |
| // Don't break them, but they don't get scroll state restoration. |
| return super.onSaveInstanceState(); |
| } |
| Parcelable superState = super.onSaveInstanceState(); |
| SavedState ss = new SavedState(superState); |
| ss.scrollPosition = mScrollY; |
| return ss; |
| } |
| |
| /** @hide */ |
| @Override |
| protected void encodeProperties(@NonNull ViewHierarchyEncoder encoder) { |
| super.encodeProperties(encoder); |
| encoder.addProperty("fillViewport", mFillViewport); |
| } |
| |
| static class SavedState extends BaseSavedState { |
| public int scrollPosition; |
| |
| SavedState(Parcelable superState) { |
| super(superState); |
| } |
| |
| public SavedState(Parcel source) { |
| super(source); |
| scrollPosition = source.readInt(); |
| } |
| |
| @Override |
| public void writeToParcel(Parcel dest, int flags) { |
| super.writeToParcel(dest, flags); |
| dest.writeInt(scrollPosition); |
| } |
| |
| @Override |
| public String toString() { |
| return "ScrollView.SavedState{" |
| + Integer.toHexString(System.identityHashCode(this)) |
| + " scrollPosition=" + scrollPosition + "}"; |
| } |
| |
| public static final @android.annotation.NonNull 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]; |
| } |
| }; |
| } |
| |
| } |
