Update text selection handles to have a minimum touch target size.

The text selection handles were traditionally sized based on the size
of the provided drawables. When these drawables are visually small, do
not restrict the size of the touch target beyond a certain minimum.

Bug 16851360

Change-Id: If6a468c7b3a9a1a21913006633f00699637751c0

core/java/android/widget/Editor.java

@@ -3158,6 +3158,7 @@ public class Editor {
         // Offset from touch position to mPosition
         private float mTouchToWindowOffsetX, mTouchToWindowOffsetY;
         protected int mHotspotX;
+        protected int mHorizontalGravity;
         // Offsets the hotspot point up, so that cursor is not hidden by the finger when moving up
         private float mTouchOffsetY;
         // Where the touch position should be on the handle to ensure a maximum cursor visibility
@@ -3172,6 +3173,8 @@ public class Editor {
         private boolean mPositionHasChanged = true;
         // Used to delay the appearance of the action popup window
         private Runnable mActionPopupShower;
+        // Minimum touch target size for handles
+        private int mMinSize;
 
         public HandleView(Drawable drawableLtr, Drawable drawableRtl) {
             super(mTextView.getContext());
@@ -3184,10 +3187,12 @@ public class Editor {
 
             mDrawableLtr = drawableLtr;
             mDrawableRtl = drawableRtl;
+            mMinSize = mTextView.getContext().getResources().getDimensionPixelSize(
+                    com.android.internal.R.dimen.text_handle_min_size);
 
             updateDrawable();
 
-            final int handleHeight = mDrawable.getIntrinsicHeight();
+            final int handleHeight = getPreferredHeight();
             mTouchOffsetY = -0.3f * handleHeight;
             mIdealVerticalOffset = 0.7f * handleHeight;
         }
@@ -3197,9 +3202,11 @@ public class Editor {
             final boolean isRtlCharAtOffset = mTextView.getLayout().isRtlCharAt(offset);
             mDrawable = isRtlCharAtOffset ? mDrawableRtl : mDrawableLtr;
             mHotspotX = getHotspotX(mDrawable, isRtlCharAtOffset);
+            mHorizontalGravity = getHorizontalGravity(isRtlCharAtOffset);
         }
 
         protected abstract int getHotspotX(Drawable drawable, boolean isRtlRun);
+        protected abstract int getHorizontalGravity(boolean isRtlRun);
 
         // Touch-up filter: number of previous positions remembered
         private static final int HISTORY_SIZE = 5;
@@ -3244,7 +3251,15 @@ public class Editor {
 
         @Override
         protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
-            setMeasuredDimension(mDrawable.getIntrinsicWidth(), mDrawable.getIntrinsicHeight());
+            setMeasuredDimension(getPreferredWidth(), getPreferredHeight());
+        }
+
+        private int getPreferredWidth() {
+            return Math.max(mDrawable.getIntrinsicWidth(), mMinSize);
+        }
+
+        private int getPreferredHeight() {
+            return Math.max(mDrawable.getIntrinsicHeight(), mMinSize);
         }
 
         public void show() {
@@ -3336,7 +3351,8 @@ public class Editor {
                 }
                 final int line = layout.getLineForOffset(offset);
 
-                mPositionX = (int) (layout.getPrimaryHorizontal(offset) - 0.5f - mHotspotX);
+                mPositionX = (int) (layout.getPrimaryHorizontal(offset) - 0.5f - mHotspotX -
+                        getHorizontalOffset() + getCursorOffset());
                 mPositionY = layout.getLineBottom(line);
 
                 // Take TextView's padding and scroll into account.
@@ -3385,10 +3401,36 @@ public class Editor {
 
         @Override
         protected void onDraw(Canvas c) {
-            mDrawable.setBounds(0, 0, mRight - mLeft, mBottom - mTop);
+            final int drawWidth = mDrawable.getIntrinsicWidth();
+            final int left = getHorizontalOffset();
+
+            mDrawable.setBounds(left, 0, left + drawWidth, mDrawable.getIntrinsicHeight());
             mDrawable.draw(c);
         }
 
+        private int getHorizontalOffset() {
+            final int width = getPreferredWidth();
+            final int drawWidth = mDrawable.getIntrinsicWidth();
+            final int left;
+            switch (mHorizontalGravity) {
+                case Gravity.LEFT:
+                    left = 0;
+                    break;
+                default:
+                case Gravity.CENTER:
+                    left = (width - drawWidth) / 2;
+                    break;
+                case Gravity.RIGHT:
+                    left = width - drawWidth;
+                    break;
+            }
+            return left;
+        }
+
+        protected int getCursorOffset() {
+            return 0;
+        }
+
         @Override
         public boolean onTouchEvent(MotionEvent ev) {
             switch (ev.getActionMasked()) {
@@ -3507,6 +3549,22 @@ public class Editor {
             return drawable.getIntrinsicWidth() / 2;
         }
 
+        @Override
+        protected int getHorizontalGravity(boolean isRtlRun) {
+            return Gravity.CENTER_HORIZONTAL;
+        }
+
+        @Override
+        protected int getCursorOffset() {
+            int offset = super.getCursorOffset();
+            final Drawable cursor = mCursorCount > 0 ? mCursorDrawable[0] : null;
+            if (cursor != null) {
+                cursor.getPadding(mTempRect);
+                offset += (cursor.getIntrinsicWidth() - mTempRect.left - mTempRect.right) / 2;
+            }
+            return offset;
+        }
+
         @Override
         public boolean onTouchEvent(MotionEvent ev) {
             final boolean result = super.onTouchEvent(ev);
@@ -3593,6 +3651,11 @@ public class Editor {
             }
         }
 
+        @Override
+        protected int getHorizontalGravity(boolean isRtlRun) {
+            return isRtlRun ? Gravity.RIGHT : Gravity.LEFT;
+        }
+
         @Override
         public int getCurrentCursorOffset() {
             return mTextView.getSelectionStart();
@@ -3636,6 +3699,11 @@ public class Editor {
             }
         }
 
+        @Override
+        protected int getHorizontalGravity(boolean isRtlRun) {
+            return isRtlRun ? Gravity.LEFT : Gravity.RIGHT;
+        }
+
         @Override
         public int getCurrentCursorOffset() {
             return mTextView.getSelectionEnd();

core/res/res/values/dimens.xml

@@ -394,4 +394,7 @@
      <dimen name="lock_pattern_dot_line_width">3dp</dimen>
      <dimen name="lock_pattern_dot_size">12dp</dimen>
      <dimen name="lock_pattern_dot_size_activated">28dp</dimen>
+
+     <dimen name="text_handle_min_size">40dp</dimen>
+
 </resources>

core/res/res/values/symbols.xml

@@ -1983,4 +1983,5 @@
   <java-symbol type="layout" name="select_dialog_singlechoice_material" />
   <java-symbol type="layout" name="select_dialog_multichoice_material" />
   <java-symbol type="array" name="no_ems_support_sim_operators" />
+  <java-symbol type="dimen" name="text_handle_min_size" />
 </resources>