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      1 /*
      2  * Copyright (C) 2013 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.inputmethod.keyboard.internal;
     18 
     19 import android.util.Log;
     20 import android.view.MotionEvent;
     21 
     22 import com.android.inputmethod.keyboard.Key;
     23 import com.android.inputmethod.keyboard.PointerTracker;
     24 import com.android.inputmethod.keyboard.PointerTracker.KeyEventHandler;
     25 import com.android.inputmethod.latin.utils.CoordinateUtils;
     26 
     27 public final class NonDistinctMultitouchHelper {
     28     private static final String TAG = NonDistinctMultitouchHelper.class.getSimpleName();
     29 
     30     private int mOldPointerCount = 1;
     31     private Key mOldKey;
     32     private int[] mLastCoords = CoordinateUtils.newInstance();
     33 
     34     public void processMotionEvent(final MotionEvent me, final KeyEventHandler keyEventHandler) {
     35         final int pointerCount = me.getPointerCount();
     36         final int oldPointerCount = mOldPointerCount;
     37         mOldPointerCount = pointerCount;
     38         // Ignore continuous multi-touch events because we can't trust the coordinates
     39         // in multi-touch events.
     40         if (pointerCount > 1 && oldPointerCount > 1) {
     41             return;
     42         }
     43 
     44         // Use only main (id=0) pointer tracker.
     45         final PointerTracker mainTracker = PointerTracker.getPointerTracker(0, keyEventHandler);
     46         final int action = me.getActionMasked();
     47         final int index = me.getActionIndex();
     48         final long eventTime = me.getEventTime();
     49         final long downTime = me.getDownTime();
     50 
     51         // In single-touch.
     52         if (oldPointerCount == 1 && pointerCount == 1) {
     53             if (me.getPointerId(index) == mainTracker.mPointerId) {
     54                 mainTracker.processMotionEvent(me, keyEventHandler);
     55                 return;
     56             }
     57             // Inject a copied event.
     58             injectMotionEvent(action, me.getX(index), me.getY(index), downTime, eventTime,
     59                     mainTracker, keyEventHandler);
     60             return;
     61         }
     62 
     63         // Single-touch to multi-touch transition.
     64         if (oldPointerCount == 1 && pointerCount == 2) {
     65             // Send an up event for the last pointer, be cause we can't trust the coordinates of
     66             // this multi-touch event.
     67             mainTracker.getLastCoordinates(mLastCoords);
     68             final int x = CoordinateUtils.x(mLastCoords);
     69             final int y = CoordinateUtils.y(mLastCoords);
     70             mOldKey = mainTracker.getKeyOn(x, y);
     71             // Inject an artifact up event for the old key.
     72             injectMotionEvent(MotionEvent.ACTION_UP, x, y, downTime, eventTime,
     73                     mainTracker, keyEventHandler);
     74             return;
     75         }
     76 
     77         // Multi-touch to single-touch transition.
     78         if (oldPointerCount == 2 && pointerCount == 1) {
     79             // Send a down event for the latest pointer if the key is different from the previous
     80             // key.
     81             final int x = (int)me.getX(index);
     82             final int y = (int)me.getY(index);
     83             final Key newKey = mainTracker.getKeyOn(x, y);
     84             if (mOldKey != newKey) {
     85                 // Inject an artifact down event for the new key.
     86                 // An artifact up event for the new key will usually be injected as a single-touch.
     87                 injectMotionEvent(MotionEvent.ACTION_DOWN, x, y, downTime, eventTime,
     88                         mainTracker, keyEventHandler);
     89                 if (action == MotionEvent.ACTION_UP) {
     90                     // Inject an artifact up event for the new key also.
     91                     injectMotionEvent(MotionEvent.ACTION_UP, x, y, downTime, eventTime,
     92                             mainTracker, keyEventHandler);
     93                 }
     94             }
     95             return;
     96         }
     97 
     98         Log.w(TAG, "Unknown touch panel behavior: pointer count is "
     99                 + pointerCount + " (previously " + oldPointerCount + ")");
    100     }
    101 
    102     private static void injectMotionEvent(final int action, final float x, final float y,
    103             final long downTime, final long eventTime, final PointerTracker tracker,
    104             final KeyEventHandler handler) {
    105         final MotionEvent me = MotionEvent.obtain(
    106                 downTime, eventTime, action, x, y, 0 /* metaState */);
    107         try {
    108             tracker.processMotionEvent(me, handler);
    109         } finally {
    110             me.recycle();
    111         }
    112     }
    113 }
    114