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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 com.android.systemui.classifier;
     18 
     19 import android.hardware.Sensor;
     20 import android.hardware.SensorEvent;
     21 import android.view.MotionEvent;
     22 
     23 /**
     24  * A classifier which looks at the proximity sensor during the gesture. It calculates the percentage
     25  * the proximity sensor showing the near state during the whole gesture
     26  */
     27 public class ProximityClassifier extends GestureClassifier {
     28     private long mGestureStartTimeNano;
     29     private long mNearStartTimeNano;
     30     private long mNearDuration;
     31     private boolean mNear;
     32     private float mAverageNear;
     33 
     34     public ProximityClassifier(ClassifierData classifierData) {
     35     }
     36 
     37     @Override
     38     public String getTag() {
     39         return "PROX";
     40     }
     41 
     42     @Override
     43     public void onSensorChanged(SensorEvent event) {
     44         if (event.sensor.getType() == Sensor.TYPE_PROXIMITY) {
     45             update(event.values[0] < event.sensor.getMaximumRange(), event.timestamp);
     46         }
     47     }
     48 
     49     @Override
     50     public void onTouchEvent(MotionEvent event) {
     51         int action = event.getActionMasked();
     52 
     53         if (action == MotionEvent.ACTION_DOWN) {
     54             mGestureStartTimeNano = event.getEventTimeNano();
     55             mNearStartTimeNano = event.getEventTimeNano();
     56             mNearDuration = 0;
     57         }
     58 
     59         if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_CANCEL) {
     60             update(mNear, event.getEventTimeNano());
     61             long duration = event.getEventTimeNano() - mGestureStartTimeNano;
     62 
     63             if (duration == 0) {
     64                 mAverageNear = mNear ? 1.0f : 0.0f;
     65             } else {
     66                 mAverageNear = (float) mNearDuration / (float) duration;
     67             }
     68         }
     69     }
     70 
     71 
     72     /**
     73      * @param near is the sensor showing the near state right now
     74      * @param timestampNano time of this event in nanoseconds
     75      */
     76     private void update(boolean near, long timestampNano) {
     77         // This if is necessary because MotionEvents and SensorEvents do not come in
     78         // chronological order
     79         if (timestampNano > mNearStartTimeNano) {
     80             // if the state before was near then add the difference of the current time and
     81             // mNearStartTimeNano to mNearDuration.
     82             if (mNear) {
     83                 mNearDuration += timestampNano - mNearStartTimeNano;
     84             }
     85 
     86             // if the new state is near, set mNearStartTimeNano equal to this moment.
     87             if (near) {
     88                 mNearStartTimeNano = timestampNano;
     89             }
     90         }
     91         mNear = near;
     92     }
     93 
     94     @Override
     95     public float getFalseTouchEvaluation(int type) {
     96         return ProximityEvaluator.evaluate(mAverageNear, type);
     97     }
     98 }
     99