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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.KeyDetector;
     24 import com.android.inputmethod.keyboard.PointerTracker;
     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 static final int MAIN_POINTER_TRACKER_ID = 0;
     31     private int mOldPointerCount = 1;
     32     private Key mOldKey;
     33     private int[] mLastCoords = CoordinateUtils.newInstance();
     34 
     35     public void processMotionEvent(final MotionEvent me, final KeyDetector keyDetector) {
     36         final int pointerCount = me.getPointerCount();
     37         final int oldPointerCount = mOldPointerCount;
     38         mOldPointerCount = pointerCount;
     39         // Ignore continuous multi-touch events because we can't trust the coordinates
     40         // in multi-touch events.
     41         if (pointerCount > 1 && oldPointerCount > 1) {
     42             return;
     43         }
     44 
     45         // Use only main pointer tracker.
     46         final PointerTracker mainTracker = PointerTracker.getPointerTracker(
     47                 MAIN_POINTER_TRACKER_ID);
     48         final int action = me.getActionMasked();
     49         final int index = me.getActionIndex();
     50         final long eventTime = me.getEventTime();
     51         final long downTime = me.getDownTime();
     52 
     53         // In single-touch.
     54         if (oldPointerCount == 1 && pointerCount == 1) {
     55             if (me.getPointerId(index) == mainTracker.mPointerId) {
     56                 mainTracker.processMotionEvent(me, keyDetector);
     57                 return;
     58             }
     59             // Inject a copied event.
     60             injectMotionEvent(action, me.getX(index), me.getY(index), downTime, eventTime,
     61                     mainTracker, keyDetector);
     62             return;
     63         }
     64 
     65         // Single-touch to multi-touch transition.
     66         if (oldPointerCount == 1 && pointerCount == 2) {
     67             // Send an up event for the last pointer, be cause we can't trust the coordinates of
     68             // this multi-touch event.
     69             mainTracker.getLastCoordinates(mLastCoords);
     70             final int x = CoordinateUtils.x(mLastCoords);
     71             final int y = CoordinateUtils.y(mLastCoords);
     72             mOldKey = mainTracker.getKeyOn(x, y);
     73             // Inject an artifact up event for the old key.
     74             injectMotionEvent(MotionEvent.ACTION_UP, x, y, downTime, eventTime,
     75                     mainTracker, keyDetector);
     76             return;
     77         }
     78 
     79         // Multi-touch to single-touch transition.
     80         if (oldPointerCount == 2 && pointerCount == 1) {
     81             // Send a down event for the latest pointer if the key is different from the previous
     82             // key.
     83             final int x = (int)me.getX(index);
     84             final int y = (int)me.getY(index);
     85             final Key newKey = mainTracker.getKeyOn(x, y);
     86             if (mOldKey != newKey) {
     87                 // Inject an artifact down event for the new key.
     88                 // An artifact up event for the new key will usually be injected as a single-touch.
     89                 injectMotionEvent(MotionEvent.ACTION_DOWN, x, y, downTime, eventTime,
     90                         mainTracker, keyDetector);
     91                 if (action == MotionEvent.ACTION_UP) {
     92                     // Inject an artifact up event for the new key also.
     93                     injectMotionEvent(MotionEvent.ACTION_UP, x, y, downTime, eventTime,
     94                             mainTracker, keyDetector);
     95                 }
     96             }
     97             return;
     98         }
     99 
    100         Log.w(TAG, "Unknown touch panel behavior: pointer count is "
    101                 + pointerCount + " (previously " + oldPointerCount + ")");
    102     }
    103 
    104     private static void injectMotionEvent(final int action, final float x, final float y,
    105             final long downTime, final long eventTime, final PointerTracker tracker,
    106             final KeyDetector keyDetector) {
    107         final MotionEvent me = MotionEvent.obtain(
    108                 downTime, eventTime, action, x, y, 0 /* metaState */);
    109         try {
    110             tracker.processMotionEvent(me, keyDetector);
    111         } finally {
    112             me.recycle();
    113         }
    114     }
    115 }
    116