Android簡單步驟利用方向傳感器實現指南針

步驟1:新建一個項目Compass,並將一張指南針圖片導入到res/drawable-hdpi目錄中

步驟2:設計應用的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>

步驟3：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;  
      
    /** 傳感器管理器 */
    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  
        //獲取系統服務（SENSOR_SERVICE)返回一個SensorManager 對象  
        manager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);  
    }  
      
    @Override
    protected void onResume() {  
        /** 
         *  獲取方向傳感器 
         *  通過SensorManager對象獲取相應的Sensor類型的對象 
         */
        Sensor sensor = manager.getDefaultSensor(Sensor.TYPE_ORIENTATION);  
        //應用在前台時候注冊監聽器  
        manager.registerListener(listener, sensor,  
                SensorManager.SENSOR_DELAY_GAME);  
        super.onResume();  
    }  
      
    @Override
    protected void onPause() {  
        //應用不在前台時候銷毀掉監聽器  
        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  
            /**動畫效果*/
            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) {  
      
        }  
      
    }  
}

步驟4: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>