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      1 /*
      2  * Copyright (C) 2015 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 android.view;
     18 
     19 import android.annotation.UnsupportedAppUsage;
     20 import android.os.Looper;
     21 
     22 /**
     23  * Similar to {@link InputEventReceiver}, but batches events to vsync boundaries when possible.
     24  * @hide
     25  */
     26 public class BatchedInputEventReceiver extends InputEventReceiver {
     27     Choreographer mChoreographer;
     28     private boolean mBatchedInputScheduled;
     29 
     30     @UnsupportedAppUsage
     31     public BatchedInputEventReceiver(
     32             InputChannel inputChannel, Looper looper, Choreographer choreographer) {
     33         super(inputChannel, looper);
     34         mChoreographer = choreographer;
     35     }
     36 
     37     @Override
     38     public void onBatchedInputEventPending() {
     39         scheduleBatchedInput();
     40     }
     41 
     42     @Override
     43     public void dispose() {
     44         unscheduleBatchedInput();
     45         super.dispose();
     46     }
     47 
     48     void doConsumeBatchedInput(long frameTimeNanos) {
     49         if (mBatchedInputScheduled) {
     50             mBatchedInputScheduled = false;
     51             if (consumeBatchedInputEvents(frameTimeNanos) && frameTimeNanos != -1) {
     52                 // If we consumed a batch here, we want to go ahead and schedule the
     53                 // consumption of batched input events on the next frame. Otherwise, we would
     54                 // wait until we have more input events pending and might get starved by other
     55                 // things occurring in the process. If the frame time is -1, however, then
     56                 // we're in a non-batching mode, so there's no need to schedule this.
     57                 scheduleBatchedInput();
     58             }
     59         }
     60     }
     61 
     62     private void scheduleBatchedInput() {
     63         if (!mBatchedInputScheduled) {
     64             mBatchedInputScheduled = true;
     65             mChoreographer.postCallback(Choreographer.CALLBACK_INPUT, mBatchedInputRunnable, null);
     66         }
     67     }
     68 
     69     private void unscheduleBatchedInput() {
     70         if (mBatchedInputScheduled) {
     71             mBatchedInputScheduled = false;
     72             mChoreographer.removeCallbacks(
     73                     Choreographer.CALLBACK_INPUT, mBatchedInputRunnable, null);
     74         }
     75     }
     76 
     77     private final class BatchedInputRunnable implements Runnable {
     78         @Override
     79         public void run() {
     80             doConsumeBatchedInput(mChoreographer.getFrameTimeNanos());
     81         }
     82     }
     83     private final BatchedInputRunnable mBatchedInputRunnable = new BatchedInputRunnable();
     84 }
     85