Android 利用方向传感器实现 指南针

step1:新建一个项目Compass,并将一张指南针图片导入到res/drawable-hdpi目录中

step2:设计应用的UI界面,main.xml

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

step3：MainActivity.java

import android.app.Activity;
import android.content.Context;
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;

public class MainActivity extends Activity {

 private ImageView imageView;

 /** 传感器管理器 */
 private SensorManager manager;

 private SensorListener listener = new SensorListener();

 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);

  imageView = (ImageView) this.findViewById(R.id.imageView);
  imageView.setKeepScreenOn(true);//屏幕高亮
  //获取系统服务（SENSOR_SERVICE)返回一个SensorManager 对象
  manager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
 }

 @Override
 protected void onResume() {
  /**
  *  获取方向传感器
  *  通过SensorManager对象获取相应的Sensor类型的对象
  */
  Sensor sensor = manager.getDefaultSensor(Sensor.TYPE_ORIENTATION);
  //应用在前台时候注册监听器
  manager.registerListener(listener, sensor,
    SensorManager.SENSOR_DELAY_GAME);
  super.onResume();
 }

 @Override
 protected void onPause() {
  //应用不在前台时候销毁掉监听器
  manager.unregisterListener(listener);
  super.onPause();
 }

 private final class SensorListener implements SensorEventListener {

  private float predegree = 0;

  @Override
  public void onSensorChanged(SensorEvent event) {
   /**
    *  values[0]: x-axis 方向加速度
   　　 values[1]: y-axis 方向加速度
   　　 values[2]: z-axis 方向加速度
    */
   float degree = event.values[0];// 存放了方向值
   /**动画效果*/
   RotateAnimation animation = new RotateAnimation(predegree, degree,
     Animation.RELATIVE_TO_SELF,0.5f,Animation.RELATIVE_TO_SELF,0.5f);
   animation.setDuration(200);
   imageView.startAnimation(animation);
   predegree=-degree;
   
   /**
   float x=event.values[SensorManager.DATA_X];
   float y=event.values[SensorManager.DATA_Y];
   float z=event.values[SensorManager.DATA_Z];
   Log.i("XYZ", "x="+(int)x+",y="+(int)y+",z="+(int)z);
   */
  }

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

  }

 }
}

step4:AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="cn.roco.sensor"
      android:versionCode="1"
      android:versionname="1.0">
    <uses-sdk android:minSdkVersion="8" />

    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name="MainActivity"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    </application>
</manifest>