Android IPC通信bindService不能回调onServiceConnected方法

[SugarAnnie]

Server端：
用aidl定义了一个接口，接口中有个add方法，然后写了一个Service实现了这个接口

public class CalculateService extends Service {
    private static final String TAG = "CalculateService";

    @Override
    public void onCreate() {
        super.onCreate();
    }

    @Override
    public IBinder onBind(Intent arg0) {
        // TODO Auto-generated method stub
        Log.d(TAG, "onBind()");
        return mBinder;
    }

    private final ICalculateInterface.Stub mBinder = new ICalculateInterface.Stub() {

        @Override
        public int add(int a, int b) throws RemoteException {
            Log.d(TAG, "远程计算中...");
            Log.d(TAG, a + " + " + b + " = " + (a + b));

            return a + b;
        }

        @Override
        public void basicTypes(int anInt, long aLong, boolean aBoolean, float aFloat, double aDouble, String aString) throws RemoteException {

        }
    };
}

在AndroidManifest.xml中注册了服务

<service
    android:name=".CalculateService">
        <intent-filter>
             <action android:name="CalculateService"/>
        </intent-filter>
 </service>

Client端

public class MainActivity extends AppCompatActivity {
    private final String TAG = "MainActivity";
    private EditText num1 = null;
    private EditText num2 = null;
    private TextView result = null;
    private Button btn = null;
    private ICalculateInterface calculateInterface = null;

    ServiceConnection serviceConnection = new ServiceConnection() {

        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            calculateInterface = ICalculateInterface.Stub.asInterface(service);
            if (calculateInterface == null) {
                Log.d(TAG, "calculateInterface 对象为空");
            } else {
                Log.d(TAG, "获取 calculateInterface 对象");
            }
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
            calculateInterface = null;
        }
    };

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

        num1 = (EditText) findViewById(R.id.et1);
        num2 = (EditText) findViewById(R.id.et2);
        result = (TextView) findViewById(R.id.tv4);
        btn = (Button) findViewById(R.id.btn);

        btn.setOnClickListener(new ButtonClickListener());
    }

    class ButtonClickListener implements View.OnClickListener {

        @Override
        public void onClick(View v) {
            Intent intent = new Intent("CalculateService");
            Intent eintent = new Intent(createExplicitFromImplicitIntent(MainActivity.this, intent));
            bindService(eintent, serviceConnection, Context.BIND_AUTO_CREATE);
            if (calculateInterface == null)
                Log.d(TAG, "未连接服务器");
            try {
                int res = calculateInterface.add(Integer.parseInt(num1.getText().toString()), Integer.parseInt(num2.getText().toString()));
                result.setText(res + "");
            } catch (RemoteException e) {
                e.printStackTrace();
            }
        }
    }

    public static Intent createExplicitFromImplicitIntent(Context context, Intent implicitIntent) {
        // Retrieve all services that can match the given intent
        PackageManager pm = context.getPackageManager();
        List<ResolveInfo> resolveInfo = pm.queryIntentServices(implicitIntent, 0);

        // Make sure only one match was found
        if (resolveInfo == null || resolveInfo.size() != 1) {
            return null;
        }

        // Get component info and create ComponentName
        ResolveInfo serviceInfo = resolveInfo.get(0);
        String packageName = serviceInfo.serviceInfo.packageName;
        String className = serviceInfo.serviceInfo.name;
        ComponentName component = new ComponentName(packageName, className);

        // Create a new intent. Use the old one for extras and such reuse
        Intent explicitIntent = new Intent(implicitIntent);

        // Set the component to be explicit
        explicitIntent.setComponent(component);

        return explicitIntent;
    }
}

运行的时候int res = calculateInterface.add那行报错：
java.lang.NullPointerException: Attempt to invoke interface method 'int com.cumt.aidl.ICalculateInterface.add(int, int)' on a null object reference
打印“未连接服务器”，onServiceConnected中的代码也没有执行
求大神帮忙看看我哪里学错了，或者少些了什么？？

[SugarAnnie]

找到原因了，把下面这几行从onClick()方法中移到onCreate方法中就可以了

Intent intent = new Intent();
intent.setAction("CalculateService");
intent.setPackage("com.cumt.aidldemoserver");
 bindService(intent, serviceConnection, Context.BIND_AUTO_CREATE);

[SugarAnnie]

但是不知道原因是什么，求大神赐教！！

[focuseyes]

bindService() 方法不是你定义的内部类的方法，