Android实现电子罗盘(指南针)方向传感器的应用

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"   android:layout_width="match_parent"   android:layout_height="match_parent"   android:orientation="vertical"    android:gravity="center"   >   <ImageView     android:id="@+id/compass_imageView"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:src="@drawable/compass" /> </LinearLayout> 

import android.app.Activity; import android.hardware.Sensor; import android.hardware.SensorEvent; import android.hardware.SensorEventListener; import android.hardware.SensorManager; import android.os.Bundle; import android.view.animation.Animation; import android.view.animation.RotateAnimation; import android.widget.ImageView; /**  * 电子罗盘 方向传感器  */ public class ComPassActivity extends Activity implements SensorEventListener {   private ImageView imageView;   private float currentDegree = 0f;   public void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.compass);     imageView = (ImageView) findViewById(R.id.compass_imageView);     // 传感器管理器     SensorManager sm = (SensorManager) getSystemService(SENSOR_SERVICE);     // 注册传感器(Sensor.TYPE_ORIENTATION(方向传感器);SENSOR_DELAY_FASTEST(0毫秒延迟);     // SENSOR_DELAY_GAME(20,000毫秒延迟)、SENSOR_DELAY_UI(60,000毫秒延迟))     sm.registerListener(ComPassActivity.this,         sm.getDefaultSensor(Sensor.TYPE_ORIENTATION),         SensorManager.SENSOR_DELAY_FASTEST);   }   //传感器报告新的值(方向改变)   public void onSensorChanged(SensorEvent event) {     if (event.sensor.getType() == Sensor.TYPE_ORIENTATION) {       float degree = event.values[0];       /*       RotateAnimation类：旋转变化动画类       参数说明:       fromDegrees：旋转的开始角度。       toDegrees：旋转的结束角度。       pivotXType：X轴的伸缩模式，可以取值为ABSOLUTE、RELATIVE_TO_SELF、RELATIVE_TO_PARENT。       pivotXValue：X坐标的伸缩值。       pivotYType：Y轴的伸缩模式，可以取值为ABSOLUTE、RELATIVE_TO_SELF、RELATIVE_TO_PARENT。       pivotYValue：Y坐标的伸缩值       */       RotateAnimation ra = new RotateAnimation(currentDegree, -degree,           Animation.RELATIVE_TO_SELF, 0.5f,           Animation.RELATIVE_TO_SELF, 0.5f);       //旋转过程持续时间       ra.setDuration(200);       //罗盘图片使用旋转动画       imageView.startAnimation(ra);       currentDegree = -degree;     }   }   //传感器精度的改变   public void onAccuracyChanged(Sensor sensor, int accuracy) {   } }