android开发 - 传感器

传感器，分为方向，加速度（重力），光线，磁场，距离（临近性），温度等


 方向传感器         Sensor.TYPE_ORIENTATION


 加速度(重力)传感器 Sensor.TYPE_ACCELEROMETER


 光线传感器         Sensor.TYPE_LIGHT


 磁场传感器         Sensor.TYPE_MAGNETIC_FIELD
 距离(临近性)传感器 Sensor.TYPE_PROXIMITY


 温度传感器


          Sensor.TYPE_TEMPERATURE








 例子代码          指南针 


 0   代表北  (North)


 90  代表东  (East)


 180 代表南  (South)


 270 代表西  (West)




 上北  下南   左西   右东








 xml布局


 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:paddingBottom="@dimen/activity_vertical_margin"
     android:paddingLeft="@dimen/activity_horizontal_margin"
     android:paddingRight="@dimen/activity_horizontal_margin"
     android:paddingTop="@dimen/activity_vertical_margin"
     tools:context=".MainActivity" >


     <ImageView 
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         android:src="@drawable/zhinanzhen" 
         android:id="@+id/imageView"/>


 </RelativeLayout>








 java代码


 public class MainActivity extends Activity {
private ImageView imageView;
private SensorManager sensorManager;
private MyListener listener;

/*
* (non-Javadoc)
* @see android.app.Activity#onCreate(android.os.Bundle)
* 由于传感器会很耗电，所以一般不在onCreate方法里创建，一般就在onResume()里创建
*/
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);


imageView = (ImageView) this.findViewById(R.id.imageView);
//保持屏幕高亮，不黑屏
imageView.setKeepScreenOn(true);
//得到传感器的服务
sensorManager = (SensorManager)getSystemService(Context.SENSOR_SERVICE);
}


@Override
protected void onResume() { 
super.onResume();
//获取传感器
Sensor sensor = sensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION);
sensorManager.registerListener(listener, sensor,SensorManager.SENSOR_DELAY_GAME);
}

private final class MyListener implements SensorEventListener{ 
private float degree=0;//默认是0开始
@Override
public void onSensorChanged(SensorEvent event) { 
//获取方向值
float fval = event.values[0];
//现在需要旋转图片，所以需要使用  RotateAnimation
   RotateAnimation animation = new RotateAnimation(degree,-fval,
    Animation.RELATIVE_TO_SELF,0.5f,
    Animation.RELATIVE_TO_SELF,0.5f);
   animation.setDuration(200);
   imageView.startAnimation(animation);
   degree = -fval;
}


@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) { 

} 
}


@Override
protected void onPause() {
sensorManager.unregisterListener(listener);
super.onPause();
}


 }