Home | History | Annotate | Download | only in classifier 
      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.incallui.answer.impl.classifier;
     18 
     19 import android.hardware.Sensor;
     20 import android.hardware.SensorEvent;
     21 import android.view.MotionEvent;
     22 import java.util.concurrent.TimeUnit;
     23 
     24 /**
     25  * A classifier which looks at the proximity sensor during the gesture. It calculates the percentage
     26  * the proximity sensor showing the near state during the whole gesture
     27  */
     28 class ProximityClassifier extends GestureClassifier {
     29   private long mGestureStartTimeNano;
     30   private long mNearStartTimeNano;
     31   private long mNearDuration;
     32   private boolean mNear;
     33   private float mAverageNear;
     34 
     35   public ProximityClassifier(ClassifierData classifierData) {}
     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 = TimeUnit.MILLISECONDS.toNanos(event.getEventTime());
     55       mNearStartTimeNano = TimeUnit.MILLISECONDS.toNanos(event.getEventTime());
     56       mNearDuration = 0;
     57     }
     58 
     59     if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_CANCEL) {
     60       update(mNear, TimeUnit.MILLISECONDS.toNanos(event.getEventTime()));
     61       long duration = TimeUnit.MILLISECONDS.toNanos(event.getEventTime()) - 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    * @param near is the sensor showing the near state right now
     73    * @param timestampNano time of this event in nanoseconds
     74    */
     75   private void update(boolean near, long timestampNano) {
     76     // This if is necessary because MotionEvents and SensorEvents do not come in
     77     // chronological order
     78     if (timestampNano > mNearStartTimeNano) {
     79       // if the state before was near then add the difference of the current time and
     80       // mNearStartTimeNano to mNearDuration.
     81       if (mNear) {
     82         mNearDuration += timestampNano - mNearStartTimeNano;
     83       }
     84 
     85       // if the new state is near, set mNearStartTimeNano equal to this moment.
     86       if (near) {
     87         mNearStartTimeNano = timestampNano;
     88       }
     89     }
     90     mNear = near;
     91   }
     92 
     93   @Override
     94   public float getFalseTouchEvaluation() {
     95     return ProximityEvaluator.evaluate(mAverageNear);
     96   }
     97 }
     98