Binder mechanisam to update UI in android

Question

In my project I am using binder mechanism to communicate to remote service. The remote service class will call JNI function and updates to UI for every 10 seconds. The JNI function has below code

static int n = 100;
  return ++n;

This JNI function calling in Service class and updating to UI like below

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

        private final Handler serviceHandler = new Handler();

        @Override
        public void onCreate() {
            // TODO Auto-generated method stub
            super.onCreate();  

            System.out.println("inside service onCreate");
            Log.d(TAG, "entered onStart");
            serviceHandler.removeCallbacks(sendUpdatesToUI);
            serviceHandler.postDelayed(sendUpdatesToUI, 1000); // 1 second      
        }

1.      private IMyService.Stub bioStub = new IMyService.Stub() {
2.          
3.          @Override
4.          public int intFromJNI() throws RemoteException {
5.              // TODO Auto-generated method stub  


6.              int libData = Abcd.intFromJNI();
7.              System.out.println("inside ****** stub"+libData);
8.              return libData;         
            }       
        };      


        @Override
        public IBinder onBind(Intent arg0) {

                    // TODO Auto-generated method stub
            System.out.println("inside binder ");       
            return bioStub; 
        }   

        private Runnable sendUpdatesToUI = new Runnable() {
            public void run() {

                Log.d(TAG, "entered Runnable");

                     try {
                        bioStub.intFromJNI();
                        serviceHandler.postDelayed(this, 10000); 
                    } catch (RemoteException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }       

            }
        }; 



    }

This service class is calling in Activty



     @Override
            protected void onResume() {
                // TODO Auto-generated method stub
                super.onResume();

                Intent serviceIntent=new Intent();
                serviceIntent.setClass(context, MyService.class);
                boolean ok=bindService(serviceIntent, mServiceConnection , Context.BIND_AUTO_CREATE);
                Log.v("ok", String.valueOf(ok));
            }

            private ServiceConnection mServiceConnection=new ServiceConnection(){

                @Override
                public void onServiceConnected(ComponentName arg0, IBinder service) {
                    // TODO Auto-generated method stub


                     System.out.println("inside ServiceConnection");
                        myService = IMyService.Stub.asInterface(service);

                    try {

                         Log.d("Client", "entered mServiceConnection");             
8.                       int jniValue = myService.intFromJNI();                      
9.                       System.out.println("value if JNI==>"+jniValue);             
10.                      
                    } catch (RemoteException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }

                }

                @Override
                public void onServiceDisconnected(ComponentName arg0) {
                    // TODO Auto-generated method stub

                }

            };

Here my problem is, The service class is not updating UI for every 10 seconds and the value is not incremeting in UI but the value is incrementing for every 10 seconds in service class i.e the print statement below is updating for every 10 seconds which is in line Number 7 in above code(Service).

System.out.println("inside ****** stub"+libData);

But I want to it update in UI also. i.e the statement line num 10.

System.out.println("value if JNI==>"+jniValue); 

I`t is not happening in my code . How to solve this one .`

score 1 · Accepted Answer · answered May 30 '13 at 09:07

You are missing any way for the Service to tell the Activity about new events. The call from the Activity to the Service, intFromJNI, is a one-off function call which happens just once - it has no ongoing responsibility for telling the UI about changes in future.

You should add some listener class. For example, add IMyServiceListener.aidl with something like this:

package com.something;

interface IMyServiceListener {
    void valueUpdated(int newValue);
}

And then in IMyService.aidl add this:

import com.something.IMyServiceListener;

void addListener(in IMyServiceListener newListener);

Then, within your IMyService.Stub class you will need to implement addListener - you should add the resulting object to some array of listeners, and call valueUpdated on each listener, each time the value changes.

Within the activity, you should call myService.addListener and pass in some object which receives notification of the changes. You can then display that on the UI within the activity.

Binder mechanisam to update UI in android

1 Answers1