Text selection handles correctly scroll

Bug 3416154

The origin of the problem is new display optimisations that enable
a scrollView to be scrolled without calling the onDraw method of its
children. As a result, the handles' positions were not updated on scroll.

DropDown popup menu have an integrated scroll listener that will fix the
problem. Using these indead is the first part of the solution.

The next problem is that when they get hidden, these popups try to move their
parent (the TextView in our case) which creates a scroll conflict. Fixed by
overriding findDropDownPosition.

Finally, when the handles get invisible, a new scroll listener has to be
installed that will show them back in case the view is scrolled back.

This is also an important step to fix Bug 3441308 (selectable text in list
views).

Debugging find outs:
Small optimization in PopupWindow to avoir unregistering then registering
back the listener when it is updated.

getHandle().show(); is not needed since updatePosition will do it through
moveTo().

Change-Id: I6bf6a3649538328257734ed1e651b23b889d65d9

1 files changed, 92 insertions, 72 deletions

diff --git a/core/java/android/widget/TextView.java b/core/java/android/widget/TextView.java
index c4d95b26c9ea..6791a1d22e46 100644
--- a/core/java/android/widget/TextView.java
+++ b/core/java/android/widget/TextView.java
@@ -3873,9 +3873,6 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
 
     private void registerForPreDraw() {
         final ViewTreeObserver observer = getViewTreeObserver();
-        if (observer == null) {
-            return;
-        }
 
         if (mPreDrawState == PREDRAW_NOT_REGISTERED) {
             observer.addOnPreDrawListener(this);
@@ -3961,15 +3958,13 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
         }
 
         final ViewTreeObserver observer = getViewTreeObserver();
-        if (observer != null) {
-            // No need to create the controller.
-            // The get method will add the listener on controller creation.
-            if (mInsertionPointCursorController != null) {
-                observer.addOnTouchModeChangeListener(mInsertionPointCursorController);
-            }
-            if (mSelectionModifierCursorController != null) {
-                observer.addOnTouchModeChangeListener(mSelectionModifierCursorController);
-            }
+        // No need to create the controller.
+        // The get method will add the listener on controller creation.
+        if (mInsertionPointCursorController != null) {
+            observer.addOnTouchModeChangeListener(mInsertionPointCursorController);
+        }
+        if (mSelectionModifierCursorController != null) {
+            observer.addOnTouchModeChangeListener(mSelectionModifierCursorController);
         }
     }
 
@@ -3978,18 +3973,16 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
         super.onDetachedFromWindow();
 
         final ViewTreeObserver observer = getViewTreeObserver();
-        if (observer != null) {
-            if (mPreDrawState != PREDRAW_NOT_REGISTERED) {
-                observer.removeOnPreDrawListener(this);
-                mPreDrawState = PREDRAW_NOT_REGISTERED;
-            }
-            // No need to create the controller, as getXXController would.
-            if (mInsertionPointCursorController != null) {
-                observer.removeOnTouchModeChangeListener(mInsertionPointCursorController);
-            }
-            if (mSelectionModifierCursorController != null) {
-                observer.removeOnTouchModeChangeListener(mSelectionModifierCursorController);
-            }
+        if (mPreDrawState != PREDRAW_NOT_REGISTERED) {
+            observer.removeOnPreDrawListener(this);
+            mPreDrawState = PREDRAW_NOT_REGISTERED;
+        }
+        // No need to create the controller, as getXXController would.
+        if (mInsertionPointCursorController != null) {
+            observer.removeOnTouchModeChangeListener(mInsertionPointCursorController);
+        }
+        if (mSelectionModifierCursorController != null) {
+            observer.removeOnTouchModeChangeListener(mSelectionModifierCursorController);
         }
 
         if (mError != null) {
@@ -4290,10 +4283,8 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
 
         if (mPreDrawState == PREDRAW_DONE) {
             final ViewTreeObserver observer = getViewTreeObserver();
-            if (observer != null) {
-                observer.removeOnPreDrawListener(this);
-                mPreDrawState = PREDRAW_NOT_REGISTERED;
-            }
+            observer.removeOnPreDrawListener(this);
+            mPreDrawState = PREDRAW_NOT_REGISTERED;
         }
 
         int color = mCurTextColor;
@@ -5541,8 +5532,7 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
                     ellipsisWidth);
         } else {
             if (boring == UNKNOWN_BORING) {
-                boring = BoringLayout.isBoring(mTransformed, mTextPaint,
-                                               mBoring);
+                boring = BoringLayout.isBoring(mTransformed, mTextPaint, mBoring);
                 if (boring != null) {
                     mBoring = boring;
                 }
@@ -8655,9 +8645,9 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
         }
     }
 
-    private class HandleView extends View {
+    private class HandleView extends View implements ViewTreeObserver.OnScrollChangedListener {
         private Drawable mDrawable;
-        private final PopupWindow mContainer;
+        private final ScrollingPopupWindow mContainer;
         private int mPositionX;
         private int mPositionY;
         private final CursorController mController;
@@ -8726,7 +8716,7 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
         public HandleView(CursorController controller, int pos) {
             super(TextView.this.mContext);
             mController = controller;
-            mContainer = new PopupWindow(TextView.this.mContext, null,
+            mContainer = new ScrollingPopupWindow(TextView.this.mContext, null,
                     com.android.internal.R.attr.textSelectHandleWindowStyle);
             mContainer.setSplitTouchEnabled(true);
             mContainer.setClippingEnabled(false);
@@ -8794,24 +8784,18 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
                 return;
             }
             mContainer.setContentView(this);
-            final int[] coords = mTempCoords;
-            TextView.this.getLocationInWindow(coords);
-            mContainerPositionX = coords[0] + mPositionX;
-            mContainerPositionY = coords[1] + mPositionY;
-            mContainer.showAtLocation(TextView.this, 0, mContainerPositionX, mContainerPositionY);
+            mContainerPositionX = mPositionX;
+            mContainerPositionY = mPositionY - TextView.this.getHeight();
+            mContainer.showAsDropDown(TextView.this, mContainerPositionX, mContainerPositionY);
 
             // Hide paste view when handle is moved on screen.
-            if (mPastePopupWindow != null) {
-                mPastePopupWindow.hide();
-            }
+            hidePastePopupWindow();
         }
 
         public void hide() {
             mIsDragging = false;
             mContainer.dismiss();
-            if (mPastePopupWindow != null) {
-                mPastePopupWindow.hide();
-            }
+            hidePastePopupWindow();
         }
 
         public boolean isShowing() {
@@ -8834,19 +8818,15 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
             final int compoundPaddingRight = getCompoundPaddingRight();
 
             final TextView hostView = TextView.this;
-            final int left = 0;
-            final int right = hostView.getWidth();
-            final int top = 0;
-            final int bottom = hostView.getHeight();
 
             if (mTempRect == null) {
                 mTempRect = new Rect();
             }
             final Rect clip = mTempRect;
-            clip.left = left + compoundPaddingLeft;
-            clip.top = top + extendedPaddingTop;
-            clip.right = right - compoundPaddingRight;
-            clip.bottom = bottom - extendedPaddingBottom;
+            clip.left = compoundPaddingLeft;
+            clip.top = extendedPaddingTop;
+            clip.right = hostView.getWidth() - compoundPaddingRight;
+            clip.bottom = hostView.getHeight() - extendedPaddingBottom;
 
             final ViewParent parent = hostView.getParent();
             if (parent == null || !parent.getChildVisibleRect(hostView, clip, null)) {
@@ -8858,7 +8838,8 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
             final int posX = coords[0] + mPositionX + (int) mHotspotX;
             final int posY = coords[1] + mPositionY + (int) mHotspotY;
 
-            return posX >= clip.left && posX <= clip.right &&
+            // Offset by 1 to take into account 0.5 and int rounding around getPrimaryHorizontal.
+            return posX >= clip.left - 1 && posX <= clip.right + 1 &&
                     posY >= clip.top && posY <= clip.bottom;
         }
 
@@ -8868,23 +8849,19 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
             if (isPositionVisible()) {
                 int[] coords = null;
                 if (mContainer.isShowing()) {
-                    coords = mTempCoords;
-                    TextView.this.getLocationInWindow(coords);
-                    final int containerPositionX = coords[0] + mPositionX;
-                    final int containerPositionY = coords[1] + mPositionY;
+                    final int containerPositionX = mPositionX;
+                    final int containerPositionY = mPositionY - TextView.this.getHeight();
 
                     if (containerPositionX != mContainerPositionX || 
                         containerPositionY != mContainerPositionY) {
                         mContainerPositionX = containerPositionX;
                         mContainerPositionY = containerPositionY;
 
-                        mContainer.update(mContainerPositionX, mContainerPositionY,
+                        mContainer.update(TextView.this, mContainerPositionX, mContainerPositionY,
                                 mRight - mLeft, mBottom - mTop);
 
                         // Hide paste popup window as soon as a scroll occurs.
-                        if (mPastePopupWindow != null) {
-                            mPastePopupWindow.hide();
-                        }
+                        hidePastePopupWindow();
                     }
                 } else {
                     show();
@@ -8902,9 +8879,7 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
                         mLastParentY = coords[1];
                     }
                     // Hide paste popup window as soon as the handle is dragged.
-                    if (mPastePopupWindow != null) {
-                        mPastePopupWindow.hide();
-                    }
+                    hidePastePopupWindow();
                 }
             } else {
                 hide();
@@ -9008,10 +8983,60 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
                 mPastePopupWindow.show();
             }
         }
+
+        void hidePastePopupWindow() {
+            if (mPastePopupWindow != null) {
+                mPastePopupWindow.hide();
+            }
+        }
+
+        /**
+         * A popup window, attached to a view, and that listens to scroll events in its anchors'
+         * view hierarchy, so that it is automatically moved on such events.
+         */
+        private class ScrollingPopupWindow extends PopupWindow {
+
+            private int[] mDrawingLocations = new int[2];
+
+            public ScrollingPopupWindow(Context context, AttributeSet attrs, int defStyle) {
+                super(context, attrs, defStyle);
+            }
+
+            @Override
+            public boolean findDropDownPosition(View anchor, WindowManager.LayoutParams p,
+                    int xoff, int yoff) {
+                anchor.getLocationInWindow(mDrawingLocations);
+                p.x = mDrawingLocations[0] + xoff;
+                p.y = mDrawingLocations[1] + anchor.getHeight() + yoff;
+
+                // Hide paste popup as soon as the view is scrolled.
+                hidePastePopupWindow();
+
+                if (!isPositionVisible()) {
+                    dismiss();
+                    onHandleBecomeInvisible();
+                }
+
+                return false;
+            }
+        }
+
+        public void onScrollChanged() {
+            if (isPositionVisible()) {
+                show();
+                ViewTreeObserver vto = TextView.this.getViewTreeObserver();
+                vto.removeOnScrollChangedListener(this);
+            }
+        }
+
+        public void onHandleBecomeInvisible() {
+            ViewTreeObserver vto = TextView.this.getViewTreeObserver();
+            vto.addOnScrollChangedListener(this);
+        }
     }
 
     private class InsertionPointCursorController implements CursorController {
-        private static final int DELAY_BEFORE_FADE_OUT = 4100;
+        private static final int DELAY_BEFORE_FADE_OUT = 4000;
         private static final int DELAY_BEFORE_PASTE = 2000;
         private static final int RECENT_CUT_COPY_DURATION = 15 * 1000;
 
@@ -9027,7 +9052,6 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
         public void show(int delayBeforePaste) {
             updatePosition();
             hideDelayed();
-            getHandle().show();
             removePastePopupCallback();
             final long durationSinceCutOrCopy = SystemClock.uptimeMillis() - sLastCutOrCopyTime;
             if (durationSinceCutOrCopy < RECENT_CUT_COPY_DURATION) {
@@ -9547,9 +9571,7 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
             mInsertionPointCursorController = new InsertionPointCursorController();
 
             final ViewTreeObserver observer = getViewTreeObserver();
-            if (observer != null) {
-                observer.addOnTouchModeChangeListener(mInsertionPointCursorController);
-            }
+            observer.addOnTouchModeChangeListener(mInsertionPointCursorController);
         }
 
         return mInsertionPointCursorController;
@@ -9564,9 +9586,7 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
             mSelectionModifierCursorController = new SelectionModifierCursorController();
 
             final ViewTreeObserver observer = getViewTreeObserver();
-            if (observer != null) {
-                observer.addOnTouchModeChangeListener(mSelectionModifierCursorController);
-            }
+            observer.addOnTouchModeChangeListener(mSelectionModifierCursorController);
         }
 
         return mSelectionModifierCursorController;