android bindService（）NullPointerException

Question

以下代码不断抛出空指针异常...

 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(); } } 

我猜这是因为onServiceConnected无法执行，导致绑定程序保持为空。 （but按钮将服务绑定到活动，而but2执行bind.toast（）；-按下but2时抛出异常）

基本上，问题是：为什么onServiceConnected不执行？

Answer 1

我认为，该意图应该导致服务，而不是服务中的绑定器： Intent i = new Intent(getApplicationContext(), ServiceTest.class);