Sending data via broadcast

Question

 public class MainActivity extends Activity implements SurfaceHolder.Callback 
{
private Intent intent;

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


       if (activityReceiver != null)
{ 
       IntentFilter intentFilter = new IntentFilter();
      registerReceiver(activityReceiver, intentFilter);
}

    intent = new Intent(this, Service.class);
    startService(intent);

    }

 private BroadcastReceiver activityReceiver = new BroadcastReceiver(){
    public void onReceive(Context context, Intent intent) {
    int value=intent.getIntExtra("VALUE", 0);
    txtData.setText(""+value);
    }}

}

SERVICE

public class Service extends IOIOService {
//Intent intent=new Intent(this, MainActivity.class);
private final int BUTTON_PIN = 34;
@Override
protected IOIOLooper createIOIOLooper() {
    return new BaseIOIOLooper() {
        private DigitalOutput led_;
        private DigitalInput mButton;
        int  oneTime = 0;



        @Override
        protected void setup() throws ConnectionLostException,
                InterruptedException {
            led_ = ioio_.openDigitalOutput(IOIO.LED_PIN);
            mButton = ioio_.openDigitalInput(BUTTON_PIN, DigitalInput.Spec.Mode.PULL_UP);
        }

        @Override
        public void loop() throws ConnectionLostException,
                InterruptedException {

             final boolean reading1 = mButton.read();
             if (reading1) 
             {
                 led_.write(false);
                 if(oneTime == 0)
                 {
                                             Intent intent = new Intent();
                     intent.putExtra("VALUE", 100);
                     sendBroadcast(intent);
                     oneTime = 1;
                 }

                          } 
             else 

             {
                               led_.write(true);
                             }
            Thread.sleep(100);
              }

    };
}
}
  @Override
public void onStart(Intent intent, int startId) {
    super.onStart(intent, startId);
    NotificationManager nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
    if (intent != null && intent.getAction() != null
            && intent.getAction().equals("stop")) {
        // User clicked the notification. Need to stop the service.
        nm.cancel(0);
        stopSelf();
    } else 
    {
        // Service starting. Create a notification.
        Notification notification = new Notification(
                R.drawable.ic_launcher, "IOIO service running",
                System.currentTimeMillis());
        notification
                .setLatestEventInfo(this, "IOIO Service", "Click to stop",
                        PendingIntent.getService(this, 0, new Intent(
                                "stop", null, this, this.getClass()), 0));
        notification.flags |= Notification.FLAG_ONGOING_EVENT;
        nm.notify(0, notification);
    }
}

@Override
public IBinder onBind(Intent arg0) {
    return(null);

}

} I am trying to send an integer value from service to activity using broadcast and displaying that integer into a textbox in activity. Its a simple thing but still my program is getting crashed. This is a part of my code where i have added the code for broadcasting. Can anyone please tell me whats wrong in this ? Is there anything to add more ?

@user3040168 yes its there but its been extended. original code lies in IOIOService class. hope that extends service class and its proper, else with this code hard to find out the issue. — Sush, Dec 27 '13 at 06:48
The stacktrace is not from the code you posted. You have already commented out the part that causes it (initializing an `Intent` member variable of the service at object init time when Service is not usable as Context). Please post the actual code/problem. — laalto, Dec 27 '13 at 08:07

GrIsHu · Accepted Answer · 2013-12-27T07:10:31.077

1

In your onCreate() change the below lines :

   intent = new Intent(this, Service.class);
    startService(new Intent(this, Service.class));

to this:

intent = new Intent(this, Service.class);
startService(intent);

EDITED:

//send broadcast from activity to all receivers listening to the action 
        Intent intent = new Intent();
        intent.putExtra("VALUE", 100);
        sendBroadcast(intent);

And fetch the value in the activity's onRecieve() method.

Register the Broadcast in activity:

public class MainActivity extends Activity implements SurfaceHolder.Callback 
{
private Intent intent;

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    intent = new Intent(this, Service.class);
    startService(intent);
if (activityReceiver != null)
  {
           IntentFilter intentFilter = new IntentFilter();
        //Map the intent filter to the receiver
         registerReceiver(activityReceiver, intentFilter);
  }

}

 private BroadcastReceiver activityReceiver = new BroadcastReceiver() {

    @Override
    public void onReceive(Context context, Intent intent) {
        Toast.makeText(getApplicationContext(), "received message in activity..!", Toast.LENGTH_SHORT).show();
           int value=intent.getIntExtra("VALUE", 0);
           txtData.setText(value);
    }
};


 }

edited Dec 27 '13 at 07:10

answered Dec 27 '13 at 06:18

GrIsHu

29,068
10
64
102

Tried it earlier ...still crashing – Aswathy Dec 27 '13 at 06:20
I think the issue is with the this line `Intent intent=new Intent(this, MainActivity.class);` in your service class. As its not able to get the context. Just comment this line and then check @user3040168 – GrIsHu Dec 27 '13 at 06:22
Yes it worked without crashing but the code in service is nt executed...the integer is not passed. – Aswathy Dec 27 '13 at 06:34
In your code the intent is null that is why its not getting the value. – GrIsHu Dec 27 '13 at 06:43
@GrlHu But then when i command Intent intent=new Intent(this, MainActivity.class);, it asks to intialize the "intent" – Aswathy Dec 27 '13 at 06:45
@GrlsHu should we declare "ACTION_STRING_ACTIVITY" as a constant that has to be passed to the activity – Aswathy Dec 27 '13 at 06:53
No need of that i had just shown for understanding only. Check out my updated answer. @user3040168 – GrIsHu Dec 27 '13 at 06:53
@GrlHu I have edited the code as you suggested..but nothin is passed..In on recieve method the value is displayed in the textbox...nothing is displayed... – Aswathy Dec 27 '13 at 07:02
You have not registered your activity to recieve the broadcast that is why its not getting the value. Check out the tutorial it will help you. http://androidexperinz.wordpress.com/2012/02/14/communication-between-service-and-activity-part-1/ – GrIsHu Dec 27 '13 at 07:05
Let me know if any query. – GrIsHu Dec 27 '13 at 07:06
@GrlsHu thanks i read that...am using broadcast first time....what i understood is...to recieve anything u need to create a broadcast reciever and then u need to register this reciever. am i right ? – Aswathy Dec 27 '13 at 07:31
@GrlsHu i have edited my code...could you pls check it out.. i am confused wid this line... IntentFilter intentFilter = new IntentFilter(); – Aswathy Dec 27 '13 at 08:04
Check for the null value in your broadcast reciever as i have checked in activity. – GrIsHu Dec 27 '13 at 08:15
@GrlsHu do we need to unregister it anywhere if it registered ? – Aswathy Dec 27 '13 at 08:21
Yes you need to unregister it in `onDestroy` like `@Override public void onDestroy() { super.onDestroy(); Log.d("Service", "onDestroy"); //STEP3: Unregister the receiver unregisterReceiver(activityReceiver); }` – GrIsHu Dec 27 '13 at 08:26
@GrlsHu on adding unregisteration also its nt working..ther is no error in logcat also hw cn i find the bug? – Aswathy Dec 27 '13 at 08:55
@GrlsHu logcat is error free...only the thing is it is not dispalyed – Aswathy Dec 27 '13 at 09:21
@GrlsHu i tried by passing a string and it worked...thanks my actual intention is done – Aswathy Dec 27 '13 at 09:37

score 0 · Answer 2 · answered Dec 27 '13 at 06:09

0

declare service in manifest.

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

answered Dec 27 '13 at 06:09

vipul mittal

17,343
3
41
44

score 0 · Answer 3 · answered Dec 27 '13 at 06:45

0

             // cuase for null pointer exception, intent is getting set as null first
then ur using putExtra method on it.  
              Intent intent = null;
                 intent.putExtra("VALUE", 100);
                 sendBroadcast(intent);
                 oneTime = 1;

answered Dec 27 '13 at 06:45

Sush

3,864
2
17
35

intent.putExtra("VALUE", 100);...dis line is asking for initializing the "intent"...since Intent intent=new Intent(this, MainActivity.class); is not used – Aswathy Dec 27 '13 at 06:48

Sending data via broadcast

3 Answers3