service的生命周期

 public void onClick(View v){
    	if(v==bind){
    		Log.i("aa","start");
    		Intent i = new Intent();
    		i.setClass(this, service.class);
    		bindService(i, conn, BIND_AUTO_CREATE);
    	}
    	else if (v==unbind){
    		Log.i("aa","stop");
    		unbindService(conn);
    	}
    	else if (v==start){
    		Intent intent =new Intent();
    		intent.setClass(this,service.class);
    		startService(intent);
    	}
    	else {
    		Intent intent = new Intent();
    		intent.setClass(this, service.class);
    		stopService(intent);
    	}
    }

第一次执行startService 会执行 onCreate -> onStartCommand -> onStart

第二次执行 startService 不会调用 onCreate 也不会生成新的实例，但是会再次调用 onStartCommand -> onStart （在onStart里new timer()会导致多个timer线程同时存在）

stop执行后 调用 onDestroy 服务停止后 执行stop不会有反应。

执行bind      onCreate(第一次创建服务实例，但不会开始执行服务，即不调用onStart)->onBinder->serviceConnection      

unbind 调用 onUnbinder->onDestroy 没有实例的时候会崩

	private ServiceConnection conn = new ServiceConnection(){
		@Override
		public void onServiceDisconnected(ComponentName name){
			Log.i("aaa","onServiceDisconnection");
		}
		@Override
		public void onServiceConnected(ComponentName name,IBinder service){
			Log.i("aaa","onServiceconnection");
		}
	};

public class service extends Service{
	@Override 
	public IBinder onBind(Intent intent){
		Log.i("aaa","onbinder");
		return new Binder();
	}
	@Override
	public boolean onUnbind(Intent intent){
		Log.i("aaa","onUnbind"+" "+intent.getType());
		return super.onUnbind(intent);
	}
	@Override
	public void onDestroy(){
		Log.i("aaa","onDestroy");
		super.onDestroy();
	}
	@Override
	public void onCreate(){
		Log.i("aaa","onCreate");
		super.onCreate();
	}
	@Override
	public void onStart(Intent intent , int startId){
		Log.i("aaa","onStart"+" "+startId);
		super.onStart(intent, startId);
	}
	@Override
	public int onStartCommand(Intent intent,int flags,int startId){
		Log.i("aaa","onstartCommand");
		return super.onStartCommand(intent, flags, startId);
	}
}

最后注意要把 service 加在manifest里

<service android:name="com.ServiceTest.service" android:exported="true"></service>