Java 通过活动与服务进行沟通

我正试着和服务人员沟通。我找到了这个

我确实喜欢第一个示例，但我有一个错误：

java.lang.RuntimeException:无法绑定到服务 com.example.internetcall。MyService@41763970有意{ cmp=com.example.internetcall/.MyService}： java.lang.NullPointerException:println需要一条消息

这是一项活动：

public class StartService extends Activity{

String telephoneNumber;
TextView statusTextView, numberTextView;
MyService myService;
Boolean myBound;

ServiceConnection mConnection = new ServiceConnection() {

    @Override
    public void onServiceConnected(ComponentName arg0, IBinder arg1) {
        Log.i("bnf","qui");
        LocalBinder binder = (LocalBinder) arg1;
        myService = binder.getService();
        myBound = true;
    }

    @Override
    public void onServiceDisconnected(ComponentName arg0) {
        myBound = false;
    }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    this.setContentView(R.layout.start_service_layout);

    statusTextView = (TextView) this.findViewById(R.id.statusTextView);
    numberTextView = (TextView) this.findViewById(R.id.numberTextView);

    Intent i = this.getIntent();
    telephoneNumber = i.getStringExtra("number");

    numberTextView.setText(telephoneNumber);

    if(isMyServiceRunning()){
        statusTextView.setText("Online");
        statusTextView.setTextColor(Color.GREEN);
    }else{
        statusTextView.setText("Offline");
        statusTextView.setTextColor(Color.RED);
    }

    Intent intent = new Intent(this, MyService.class);
    bindService(intent, mConnection, Context.BIND_AUTO_CREATE);

    //SupportClass.myService.setNumber(telephoneNumber);

}

private boolean isMyServiceRunning() {
    ActivityManager manager = (ActivityManager) getSystemService(ACTIVITY_SERVICE);
    for (RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)) {
        if ("com.example.internetcall.MyService".equals(service.service.getClassName().toString())) {
             return true;
        }
    }
    return false;
}



}

这是我的服务：

public class MyService extends Service{

MyWebSocket mws;
private final IBinder mBinder = new LocalBinder();
Boolean onCall;
String telephoneNumber;
String myTelephoneNumber = null;

@Override
public IBinder onBind(Intent arg0) {
    Log.i("bnf",arg0.getStringExtra("number"));
    return mBinder;
}

public class LocalBinder extends Binder {
    MyService getService() {
        Log.i("bnf","localbinder");
        // Return this instance of LocalService so clients can call public methods
        return MyService.this;
    }
}

有人知道这个问题的解决方案吗

如果我犯了一些语法错误，我很抱歉，但我不太懂英语。

您的异常发生在Log.ibnf，arg0.getStringExtranumber；arg0.getStringExtranumber为空。您没有在绑定服务的意图中传递字符串号