安卓bindService() NullPointerException

Question

下面的代码一直抛出空指针异常..。

​

public class MainActivity extends Activity implements OnClickListener{
	Button but;
	Button but2;
	LocalBinder binder;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		but = (Button) findViewById(R.id.button1);
		but.setOnClickListener(this);
		but = (Button) findViewById(R.id.button2);
	}
	
	ServiceConnection connection = new ServiceConnection(){

		@Override
		public void onServiceConnected(ComponentName arg0, IBinder arg1) {
			Log.d("D1", "connecting");
			binder = (LocalBinder) arg1;
			
		}

		@Override
		public void onServiceDisconnected(ComponentName arg0) {
			Log.d("D1", "disconnecting");
			
		}
		
	};
	
	public static class ServiceTest extends Service{

		@Override
		public IBinder onBind(Intent arg0) {
			// TODO Auto-generated method stub
			return new LocalBinder();
		}
		
		public class LocalBinder extends Binder{
			public void toast(){
				Toast.makeText(getApplicationContext(), "hope this works", Toast.LENGTH_LONG).show();
			}
		}
	}

	@Override
	public void onClick(View arg0) {
		Intent i = new Intent(getApplicationContext(), ServiceTest.LocalBinder.class);
		bindService(i, connection, Context.BIND_AUTO_CREATE);
		Toast.makeText(getApplicationContext(), "bind completed", Toast.LENGTH_LONG).show();
	}
	
	public void binderMethod(View v){
		binder.toast();
	}
}

​

我猜原因是onServiceConnected没有执行，这导致绑定器保持为空。(但是按钮在but2执行binder.toast()时将服务绑定到活动；-当按下but2时抛出异常)

最基本的问题是:为什么onServiceConnected不执行？

Answer 1

我认为，这种意图应该导致服务，而不是服务中的粘合剂：Intent i = new Intent(getApplicationContext(), ServiceTest.class);