Binding VestelService to Applications (Android)

This document explains how to use the VestelService interface in your applications. Briefly, it consists of 3 steps: Creating Folder Structure for aidl, Connecting to VestelService and Using VestelService Methods.

IVestelService.aidl

First, you need the aidl file to make calls to VestelService. This file should be placed into the following directory in your project:

The reason we have to put it there is that package of the aidl file you use in your project should match the original aidl’s package in the framework. You most likely will miss some of these directories in your project. If so, please create the folder structure like above.

package android.os;
/**
* {@hide}
*/
interface IVestelService {
    String sendCustomUartCommand(String command);
}

Connect to VestelService

The following example shows how the connection can be established. Please notice that bindService returns a boolean based on whether it has found the service or not. If it returns true, it doesn’t necessarily mean that connection has been made. There is a delay between bindService returning true and receiving the onServiceConnected callback. During this period, mService might still be null, especially if it’s used immediately after bindService. Because of this, it’s a good idea to check whether mService is null or not before using it.

// Following imports are needed
import android.os.IVestelService;
import android.os.IBinder;
import android.content.ServiceConnection;
import android.content.Intent;
import android.content.ComponentName;
 
// Declare following variables in your class for VestelService connection
private IVestelService mService;
private ServiceConnection mServiceConnection;
 
// Example function to establish VestelService connection.
private void connectToVestelService(){
    this.mServiceConnection = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder binder) {
            mService = IVestelService.Stub.asInterface(binder);
        }
        @Override
        public void onServiceDisconnected(ComponentName name) {
            mService = null;
        }
    };
    // Bind to VestelService
    bindService(new Intent("VestelServiceConnector").setPackage("android"),mServiceConnection,BIND_AUTO_CREATE);
}

Note: Please be extra careful if you’re trying to bind during the application’s lifecycle. Since onServiceConnected is executed in the same thread as the lifecycle, if you try to bind in for example onCreate method, your connection will not be made before onCreate ends no matter how much you wait. So trying to make calls during the lifecycle can be unpredictable. If you need to make some initializations after the connection is made, you can do it in onServiceConnected method instead.

To prevent leaks, you should unbind the service when you’re done with it. You can do this in onDestroy method:

@Override
public void onDestroy() {
    super.onDestroy();
    if (mServiceConnection != null) {
        unbindService(mServiceConnection);
    }
}

if (mService != null){
    mService.sendCustomUartCommand("SETRTCDATE 10:10:2010 10:10");
    mService.sendCustomUartCommand("GTZ"); // Get timezone
     
    // Read volume level
    String volStr = mService.sendCustomUartCommand("GETVOLUME");
    if (volStr != null){
        Log.i("VolumeResponse",volStr);
    }
}