AIDL 客户端未绑定到远程服务

Question

I am trying to run a simple multiplication with a remote service. I have AIDL server file declaring and defining methods. In AIDL, i have copied the same AIDL file as server under the server's package name. I have given the action for the intent filter of server's service. Still my AIDL client code is not connecting to the service.

AIDLServer:

Manifest

<service
            android:name=".CalService"
            android:enabled="true"
            android:exported="true"
            android:process=":remote">
            <intent-filter>
                <action android:name="mutliply"/>
            </intent-filter>
        </service>

ICalService.aidl

interface ICalService {
        String getMessage(String name);
        int getResult(int val1, int val2);
}

CalService.java

public class CalService extends Service {
    public CalService() {
    }

    private final ICalService.Stub binder = new ICalService.Stub() {
        @Override
        public String getMessage(String name) throws RemoteException {
            return "Hello " + name + ". The result is: ";
        }

        @Override
        public int getResult(int val1, int val2) throws RemoteException {
            return val1 * val2;
        }
    };

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

AIDLCLient:

MainActivity.java

@Override
    protected void onStart() {
        super.onStart();
        editName = (EditText) findViewById(R.id.editName);
        editVal1 = (EditText) findViewById(R.id.editVal1);
        editVal2 = (EditText) findViewById(R.id.editVal2);
        resultView = (TextView) findViewById(R.id.resultView);

        if(calService == null) {
            Log.v("CALSERVICE", "cal service null");
            Intent it = new Intent("multiply");
            it.setPackage("com.example.aidlserver");
            if(getBaseContext().getApplicationContext().bindService(
                    it, connection, Context.BIND_AUTO_CREATE
            ) == true){
                Log.v("Bind", "Bind service Succeeded");
            } else {
                Log.v("Bind", "Bind service failed");
            }
        } else {
            Log.v("Cal", "Cal Service not null");
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        unbindService(connection);
    }

    public void mutiply(View v) {
        switch (v.getId()) {
            case R.id.btnCal:
                int num1 = Integer.parseInt(editVal1.getText().toString());
                int num2 = Integer.parseInt(editVal2.getText().toString());
                try {
                    int result = calService.getResult(num1, num2);
                    String msg = calService.getMessage(editName.getText().toString());
                    resultView.setText(msg + result);
                } catch (RemoteException e) {
                    e.printStackTrace();
                }
                break;
        }
    }


    private ServiceConnection connection = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            Log.d("onServiceConnected", "Connected");
            calService = ICalService.Stub.asInterface(service);
            Toast.makeText(getApplicationContext(), "Service Connected",
                    Toast.LENGTH_SHORT).show();
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
            Log.d("onServiceDisconnected", "Disconnected");
            calService = null;
            Toast.makeText(getApplicationContext(), "Service Disconnected",
                    Toast.LENGTH_SHORT).show();
        }
    };

Answer 1

The code shows its an implicit intent used while bindService call.

Intent it = new Intent("multiply");
it.setPackage("com.example.aidlserver");

If you are above API level 21, you must update your code with an explicit intent. Please update your code with setClassName() API to make the bind service call with an explicit intent.

    Intent it = new Intent("multiply");            
    it.setClassName("com.example.aidlserver","com.example.aidlserver.CalService");
    if(getBaseContext().getApplicationContext().bindService(it, connection, Context.BIND_AUTO_CREATE) == true){
        Log.v("Bind", "Bind service Succeeded");
    } else {
        Log.v("Bind", "Bind service failed");
    }

Please note the following:

Caution: To ensure that your app is secure, always use an explicit intent when starting a Service and don't declare intent filters for your services. Using an implicit intent to start a service is a security hazard because you cannot be certain of the service that responds to the intent, and the user cannot see which service starts. Beginning with Android 5.0 (API level 21), the system throws an exception if you call bindService() with an implicit intent. Ref: https://developer.android.com/guide/components/services

Also check this too,

"To receive implicit intents, you must include the CATEGORY_DEFAULT category in the intent filter"

<category android:name="android.intent.category.DEFAULT"/>

https://developer.android.com/guide/components/intents-filters#Receiving

Answer 2

All you need is to add in client app Manifest, where you want tu bind 3rd party app Service. With the same package name you set in the Intent:

val intent = Intent("example_action")
intent.`package` = "your package name"
bindService(intent, connection, Context.BIND_AUTO_CREATE)

Manifest:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="io.github.asvid.services.client">
    <queries>
         <package android:name="io.github.asvid.services.server" />
    </queries>
...
</manifest>

Alternatively you can stay with compileSdk 29 but I don't recommend that:)