Double tap triggers text selection in a TextView. DO NOT MERGE

This is a convenient way to switch to selection mode without the
context menu. Context menu is still available and offerts Select Input method option.

Browser overloads touch events and this feature is not available in Browser which
limits the conflict with double tap zoom in browser.

Change-Id: I286504cf03733d5c2fb9bc01765f713d14bbd2f4

Author: Gilles Debunne

core/java/android/widget/TextView.java

@@ -91,6 +91,7 @@
 import android.view.MenuItem;
 import android.view.MotionEvent;
 import android.view.View;
+import android.view.ViewConfiguration;
 import android.view.ViewDebug;
 import android.view.ViewGroup;
 import android.view.ViewGroup.LayoutParams;
@@ -6820,16 +6821,17 @@ protected void onReceiveResult(int resultCode, Bundle resultData) {
     @Override
     public boolean onTouchEvent(MotionEvent event) {
         final int action = event.getActionMasked();
-        if (action == MotionEvent.ACTION_DOWN) {
-            if (hasInsertionController()) {
-                getInsertionController().onTouchEvent(event);
-            }
-            if (hasSelectionController()) {
-                getSelectionController().onTouchEvent(event);
-            }
 
-            // Reset this state; it will be re-set if super.onTouchEvent
-            // causes focus to move to the view.
+        if (mInsertionPointCursorController != null) {
+            mInsertionPointCursorController.onTouchEvent(event);
+        }
+        if (mSelectionModifierCursorController != null) {
+            mSelectionModifierCursorController.onTouchEvent(event);
+        }
+
+        if (action == MotionEvent.ACTION_DOWN) {
+        // Reset this state; it will be re-set if super.onTouchEvent
+        // causes focus to move to the view.
             mTouchFocusSelected = false;
             mScrolled = false;
         }
@@ -6847,13 +6849,6 @@ public boolean onTouchEvent(MotionEvent event) {
         }
 
         if ((mMovement != null || onCheckIsTextEditor()) && mText instanceof Spannable && mLayout != null) {
-            if (hasInsertionController()) {
-                getInsertionController().onTouchEvent(event);
-            }
-            if (hasSelectionController()) {
-                getSelectionController().onTouchEvent(event);
-            }
-
             boolean handled = false;
 
             // Save previous selection, in case this event is used to show the IME.
@@ -7782,7 +7777,7 @@ public void setOrientation(int pos) {
                 }
                 mDrawable = mSelectHandleLeft;
                 handleWidth = mDrawable.getIntrinsicWidth();
-                mHotspotX = handleWidth / 4 * 3;
+                mHotspotX = (handleWidth * 3) / 4;
                 break;
             }
 
@@ -7949,6 +7944,7 @@ public boolean onTouchEvent(MotionEvent ev) {
                 mIsDragging = true;
                 break;
             }
+
             case MotionEvent.ACTION_MOVE: {
                 final float rawX = ev.getRawX();
                 final float rawY = ev.getRawY();
@@ -7959,6 +7955,7 @@ public boolean onTouchEvent(MotionEvent ev) {
 
                 break;
             }
+
             case MotionEvent.ACTION_UP:
             case MotionEvent.ACTION_CANCEL:
                 mIsDragging = false;
@@ -8073,6 +8070,10 @@ private class SelectionModifierCursorController implements CursorController {
         private int mMinTouchOffset, mMaxTouchOffset;
         // Whether selection anchors are active
         private boolean mIsShowing;
+        // Double tap detection
+        private long mPreviousTapUpTime = 0;
+        private int mPreviousTapPositionX;
+        private int mPreviousTapPositionY;
 
         SelectionModifierCursorController() {
             mStartHandle = new HandleView(this, HandleView.LEFT);
@@ -8167,6 +8168,24 @@ public boolean onTouchEvent(MotionEvent event) {
                         // Remember finger down position, to be able to start selection from there
                         mMinTouchOffset = mMaxTouchOffset = getOffset(x, y);
 
+                        // Double tap detection
+                        long duration = SystemClock.uptimeMillis() - mPreviousTapUpTime;
+                        if (duration <= ViewConfiguration.getDoubleTapTimeout()) {
+                            final int deltaX = x - mPreviousTapPositionX;
+                            final int deltaY = y - mPreviousTapPositionY;
+                            final int distanceSquared = deltaX * deltaX + deltaY * deltaY;
+                            final int doubleTapSlop = ViewConfiguration.get(getContext()).getScaledDoubleTapSlop();
+                            final int slopSquared = doubleTapSlop * doubleTapSlop;
+                            if (distanceSquared < slopSquared) {
+                                startTextSelectionMode();
+                                // Hacky: onTapUpEvent will open a context menu with cut/copy
+                                // Prevent this by hiding handles which will be revived instead.
+                                hide();
+                            }
+                        }
+                        mPreviousTapPositionX = x;
+                        mPreviousTapPositionY = y;
+
                         break;
 
                     case MotionEvent.ACTION_POINTER_DOWN:
@@ -8178,6 +8197,10 @@ public boolean onTouchEvent(MotionEvent event) {
                             updateMinAndMaxOffsets(event);
                         }
                         break;
+
+                    case MotionEvent.ACTION_UP:
+                        mPreviousTapUpTime = SystemClock.uptimeMillis();
+                        break;
                 }
             }
             return false;