CODEWITHSUNDEEP
androidmultithreadingintentservice
Cilenco
Cilenco

Reputation: 7117

Update ListView from IntentService

I have an IntentService which creates an Overlay with the help of a WindowManager. In the WindowManager I add a View which contains a ListView. Now I want to add a new Item to the ListView in the onHandleIntent Method but if I call 

data.add("String");
adapter.notifyDataSetChanged();

the system throws an error

Only the original thread that created a view hierarchy can touch its views.

What can I do to prevent this?

Upvotes: 0

Views: 1118

Answers (2)

Dale Wilson
Dale Wilson

Reputation: 9434

The screen may only be updated by the UI thread. A service cannot guarantee that it is running in the UI thread. Therefor a service may not update the screen directly.

The solution is to send a message to the UI thread. There are many ways to do this. Here is one:

In onCreate() for the Activity attached to the screen create a message handler:

  mHandler = new Handler(Looper.getMainLooper()) {
    @Override
    public void handleMessage(Message inputMessage) {
       Update the UI here using data passed in the message.
    }
  }

Make mHandler available to the service (possibly via the intent used in StartService().

In the service send the a message to the handler:

    Message msg = mHandler.obtainMessage(...);
      ... add info to msg as necessary
    msg.sendToTarget();

These pages may help with the details:

http://developer.android.com/reference/android/os/Handler.html

and

http://developer.android.com/reference/android/os/Message.html

Upvotes: 1

Alê Oliveira
Alê Oliveira

Reputation: 6439

You could solve this by letting the Activity that holds the ListView to do the update. Activity.runOnUiThread() should do the job =]

Upvotes: 0

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