java.lang.ClassCastException: android.os.BinderPro

问题:

I have a Service that I am trying to bind to my main Activity, but I am receiving a

java.lang.ClassCastException: android.os.BinderProxy cannot be cast to com.walintukai.rubix.ConnectionService$LocalBinder.

I have declared the service in my manifest. Why is this happening?

Manifest Declaration

<service android:name=".ConnectionService" />

Service (simplified code)

public class ConnectionService extends Service {

static final String TAG = ConnectionService.class.getName();

private BluetoothAdapter mBtAdapter = null;
public BluetoothGatt mBluetoothGatt = null;
private ConnectionServiceEventListener mIRedBearServiceEventListener;
HashMap<String, BluetoothDevice> mDevices = null;
private BluetoothGattCharacteristic txCharc = null;
private final IBinder mBinder = new LocalBinder();

@Override
public IBinder onBind(Intent intent) {
    return mBinder;
}

public class LocalBinder extends Binder {
    public ConnectionService getService() {
        return ConnectionService.this;
    }
}

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

    final BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
    mBtAdapter = bluetoothManager.getAdapter();

    if (mBtAdapter == null) 
        return;

    if (mDevices == null) 
        mDevices = new HashMap<String, BluetoothDevice>();
}

@Override
public void onDestroy() {
    if (mBluetoothGatt == null)
        return;

    mBluetoothGatt.close();
    mBluetoothGatt = null;

    super.onDestroy();
}

}

Main Activity

public class MainActivity extends ActionBarActivity {

private ConnectionService service;

ServiceConnection connection = new ServiceConnection() {

    @Override
    public void onServiceDisconnected(ComponentName name) {
        Log.i("ConnectionService", "Disconnected");
        service = null;
    }

    @Override
    public void onServiceConnected(ComponentName name, IBinder service) {
        LocalBinder binder = (LocalBinder) service;
        service = (IBinder) binder.getService();

        if (service != null) {
            Log.i("RedBearService", "Connected");

        }
    }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    if (savedInstanceState == null) {
        getSupportFragmentManager().beginTransaction().add(R.id.container, ViewPagerFragment.newInstance()).commit();
    }
}

@Override
public void onStart() {
    super.onStart();
    startService();
}

@Override
public void onStop() {
    super.onStop();
    stopService();
}

private void startService() {
    Intent service = new Intent(this, ConnectionService.class);
    bindService(service, connection, Context.BIND_AUTO_CREATE);
}

private void stopService() {
    unbindService(connection);
}

}

Stacktrace

07-30 17:19:39.065: E/AndroidRuntime(20891): java.lang.ClassCastException: android.os.BinderProxy cannot be cast to com.walintukai.rubix.ConnectionService$LocalBinder
07-30 17:19:39.065: E/AndroidRuntime(20891):    at com.walintukai.rubix.MainActivity$1.onServiceConnected(MainActivity.java:58)
07-30 17:19:39.065: E/AndroidRuntime(20891):    at android.app.LoadedApk$ServiceDispatcher.doConnected(LoadedApk.java:1110)
07-30 17:19:39.065: E/AndroidRuntime(20891):    at android.app.LoadedApk$ServiceDispatcher$RunConnection.run(LoadedApk.java:1127)
07-30 17:19:39.065: E/AndroidRuntime(20891):    at android.os.Handler.handleCallback(Handler.java:733)
07-30 17:19:39.065: E/AndroidRuntime(20891):    at android.os.Handler.dispatchMessage(Handler.java:95)
07-30 17:19:39.065: E/AndroidRuntime(20891):    at android.os.Looper.loop(Looper.java:136)
07-30 17:19:39.065: E/AndroidRuntime(20891):    at android.app.ActivityThread.main(ActivityThread.java:5050)
07-30 17:19:39.065: E/AndroidRuntime(20891):    at java.lang.reflect.Method.invokeNative(Native Method)
07-30 17:19:39.065: E/AndroidRuntime(20891):    at java.lang.reflect.Method.invoke(Method.java:515)
07-30 17:19:39.065: E/AndroidRuntime(20891):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
07-30 17:19:39.065: E/AndroidRuntime(20891):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:605)
07-30 17:19:39.065: E/AndroidRuntime(20891):    at dalvik.system.NativeStart.main(Native Method)

回答1:

You've got it flipped:

public void onServiceConnected(ComponentName name, IBinder service) {
    LocalBinder binder = (LocalBinder) service;
    service = (IBinder) binder.getService();
    ...
}

should be:

public void onServiceConnected(ComponentName name, IBinder service) {
    LocalBinder binder = (LocalBinder) service;
    MainActivity.this.service = (ConnectionService) binder.getService();
    ...
}

回答2:

This question is a few years old and the accepted answer didn't work for me. Perhaps something has changed in the Android environment since the question was asked and answered.

But I stumbled on a simple solution that worked. I saw another question on SO that was trying to start 2 services and they had a similar error (Getting java.lang.ClassCastException: android.os.BinderProxy every time i declare and run two services). One of the answers (@Coeffect) mentioned that the 2 services don't necessarily run in the same process.

I got to thinking that it is possible (probable?) that in my case the activity and the service were run in different processes. So I added the android:process element to both my activity and my server, and that fixed it.

Here's an example AndroidManifest.xml. Note that both the <activity> and <service> tags include android:process=":location":

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="net.byteslinger.locationservice">

    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

    <application
        android:process=":location"
        android:allowBackup="true"
        android:icon="@mipmap/icon"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/icon"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity"
            android:process=":location"
            android:screenOrientation="portrait">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <service
            android:process=":location"
            android:name=".LocationService"
            android:enabled="true" />
    </application>

</manifest>