Android Service总结 Android Service总结及仔细讲解

package com.newcj.test;
 
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
 
public class LocalService1 extends Service {
 
  /**
   * onBind 是 Service 的虚方法，因此我们不得不实现它。
   * 返回 null，表示客服端不能建立到此服务的连接。
   */
  @Override
  public IBinder onBind(Intent intent) {
    return null;
  }
   
  @Override
  public void onCreate() {
    super.onCreate();
  }
   
  @Override
  public void onStart(Intent intent, int startId) {
    super.onStart(intent, startId);
  }
   
  @Override
  public void onDestroy() {
    super.onDestroy();
  }
 
}

// 启动一个 Activity
startActivity(new Intent(this, LocalService1.class));
...
// 停止一个 Activity
stopService(new Intent(this, LocalService1.class));

package com.newcj.test;
 
import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
 
public class LocalService extends Service {
 
  /**
   * 在 Local Service 中我们直接继承 Binder 而不是 IBinder,因为 Binder 实现了 IBinder 接口，这样我们可以少做很多工作。
   * @author newcj
   */
  public class SimpleBinder extends Binder{
    /**
     * 获取 Service 实例
     * @return
     */
    public LocalService getService(){
      return LocalService.this;
    }
     
    public int add(int a, int b){
      return a + b;
    }
  }
   
  public SimpleBinder sBinder;
   
  @Override
  public void onCreate() {
    super.onCreate();
    // 创建 SimpleBinder
    sBinder = new SimpleBinder();
  }
   
  @Override
  public IBinder onBind(Intent intent) {
    // 返回 SimpleBinder 对象
    return sBinder;
  }
 
}

package com.newcj.test;
 
import android.app.Activity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
 
public class Main extends Activity {
  private final static String TAG = "SERVICE_TEST";
  private ServiceConnection sc;
  private boolean isBind;
 
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    sc = new ServiceConnection() {
       
      @Override
      public void onServiceDisconnected(ComponentName name) {
 
      }
       
      @Override
      public void onServiceConnected(ComponentName name, IBinder service) {
        LocalService.SimpleBinder sBinder = (LocalService.SimpleBinder)service;
        Log.v(TAG, "3 + 5 = " + sBinder.add(3, 5));
        Log.v(TAG, sBinder.getService().toString());
      }
    };
    findViewById(R.id.btnBind).setOnClickListener(new OnClickListener() {
       
      @Override
      public void onClick(View v) {
        bindService(new Intent(Main.this, LocalService.class), sc, Context.BIND_AUTO_CREATE);
        isBind = true;
      }
    });
    findViewById(R.id.btnUnbind).setOnClickListener(new OnClickListener() {
       
      @Override
      public void onClick(View v) {
        if(isBind){
          unbindService(sc);
          isBind = false;
        }
      }
    });
  }
}

package com.newcj.test;
 
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
 
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.os.IBinder;
 
public class ForegroundService extends Service {
 
  private static final Class[] mStartForegroundSignature = new Class[] {
    int.class, Notification.class};
  private static final Class[] mStopForegroundSignature = new Class[] {
    boolean.class};
  private NotificationManager mNM;
  private Method mStartForeground;
  private Method mStopForeground;
  private Object[] mStartForegroundArgs = new Object[2];
  private Object[] mStopForegroundArgs = new Object[1];
   
  @Override
  public IBinder onBind(Intent intent) {
    return null;
  }
   
  @Override
  public void onCreate() {
    super.onCreate();
    mNM = (NotificationManager)getSystemService(Context.NOTIFICATION_SERVICE);
    try {
      mStartForeground = ForegroundService.class.getMethod("startForeground", mStartForegroundSignature);
      mStopForeground = ForegroundService.class.getMethod("stopForeground", mStopForegroundSignature);
    } catch (NoSuchMethodException e) {
      mStartForeground = mStopForeground = null;
    }
     // 我们并不需要为 notification.flags 设置 FLAG_ONGOING_EVENT，因为
     // 前台服务的 notification.flags 总是默认包含了那个标志位
    Notification notification = new Notification(R.drawable.icon, "Foreground Service Started.",
        System.currentTimeMillis());
    PendingIntent contentIntent = PendingIntent.getActivity(this, 0,
        new Intent(this, Main.class), 0);
    notification.setLatestEventInfo(this, "Foreground Service",
        "Foreground Service Started.", contentIntent);
    // 注意使用 startForeground ，id 为 0 将不会显示 notification
    startForegroundCompat(1, notification);
  }
   
  @Override
  public void onDestroy() {
    super.onDestroy();
    stopForegroundCompat(1);
  }
   
  // 以兼容性方式开始前台服务
  private void startForegroundCompat(int id, Notification n){
    if(mStartForeground != null){
      mStartForegroundArgs[0] = id;
      mStartForegroundArgs[1] = n;
       
      try {
        mStartForeground.invoke(this, mStartForegroundArgs);
      } catch (IllegalArgumentException e) {
        e.printStackTrace();
      } catch (IllegalAccessException e) {
        e.printStackTrace();
      } catch (InvocationTargetException e) {
        e.printStackTrace();
      }
       
      return;
    }
    setForeground(true);
    mNM.notify(id, n);
  }
   
  // 以兼容性方式停止前台服务
  private void stopForegroundCompat(int id){
    if(mStopForeground != null){
      mStopForegroundArgs[0] = Boolean.TRUE;
       
      try {
        mStopForeground.invoke(this, mStopForegroundArgs);
      } catch (IllegalArgumentException e) {
        e.printStackTrace();
      } catch (IllegalAccessException e) {
        e.printStackTrace();
      } catch (InvocationTargetException e) {
        e.printStackTrace();
      }
      return;
    }
     
    // 在 setForeground 之前调用 cancel，因为我们有可能在取消前台服务之后
    // 的那一瞬间被kill掉。这个时候 notification 便永远不会从通知一栏移除
    mNM.cancel(id);
    setForeground(false);
  }
 
}