src/com/android/music/Shaker.java

   1 package com.android.music;\r
   2 \r
   3 import android.content.Context;\r
   4 import android.hardware.Sensor;\r
   5 import android.hardware.SensorEvent;\r
   6 import android.hardware.SensorEventListener;\r
   7 import android.hardware.SensorManager;\r
   8 import android.os.SystemClock;\r
   9 \r
  10 public class Shaker {\r
  11         private SensorManager mgr = null;\r
  12         private long lastShakeTimestamp = 0;\r
  13         private double threshold = 1.0d;\r
  14         private long gap = 0;\r
  15         private Shaker.Callback cb = null;\r
  16 \r
  17         public Shaker(Context ctxt, double threshold, long gap, Shaker.Callback cb) {\r
  18                 this.threshold = threshold * threshold;\r
  19                 this.threshold = this.threshold * SensorManager.GRAVITY_EARTH\r
  20                                 * SensorManager.GRAVITY_EARTH;\r
  21                 this.gap = gap;\r
  22                 this.cb = cb;\r
  23 \r
  24                 mgr = (SensorManager) ctxt.getSystemService(Context.SENSOR_SERVICE);\r
  25                 mgr.registerListener(listener,\r
  26                                 mgr.getDefaultSensor(Sensor.TYPE_ACCELEROMETER),\r
  27                                 SensorManager.SENSOR_DELAY_UI);\r
  28         }\r
  29 \r
  30         public void close() {\r
  31                 mgr.unregisterListener(listener);\r
  32         }\r
  33 \r
  34         private void isShaking() {\r
  35                 long now = SystemClock.uptimeMillis();\r
  36                 try {\r
  37                         if (lastShakeTimestamp == 0) {\r
  38                                 lastShakeTimestamp = now;\r
  39 \r
  40                                 if (cb != null) {\r
  41                                         cb.shakingStarted();\r
  42                                 }\r
  43                         } else {\r
  44                                 lastShakeTimestamp = now;\r
  45                         }\r
  46                 } catch (NullPointerException e) {\r
  47 \r
  48                 }\r
  49         }\r
  50 \r
  51         private void isNotShaking() {\r
  52                 long now = SystemClock.uptimeMillis();\r
  53 \r
  54                 if (lastShakeTimestamp > 0) {\r
  55                         if (now - lastShakeTimestamp > gap) {\r
  56                                 lastShakeTimestamp = 0;\r
  57 \r
  58                                 if (cb != null) {\r
  59                                         cb.shakingStopped();\r
  60                                 }\r
  61                         }\r
  62                 }\r
  63         }\r
  64 \r
  65         public interface Callback {\r
  66                 void shakingStarted();\r
  67 \r
  68                 void shakingStopped();\r
  69         }\r
  70 \r
  71         private SensorEventListener listener = new SensorEventListener() {\r
  72                 public void onSensorChanged(SensorEvent e) {\r
  73                         if (e.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {\r
  74                                 double netForce = e.values[0] * e.values[0];\r
  75 \r
  76                                 netForce += e.values[1] * e.values[1];\r
  77                                 netForce += e.values[2] * e.values[2];\r
  78 \r
  79                                 if (threshold < netForce) {\r
  80                                         isShaking();\r
  81                                 } else {\r
  82                                         isNotShaking();\r
  83                                 }\r
  84                         }\r
  85                 }\r
  86 \r
  87                 public void onAccuracyChanged(Sensor sensor, int accuracy) {\r
  88                         // unused\r
  89                 }\r
  90         };\r
  91 }