How to handle data output in an Observer?

Posted by Mannaz on Stack Overflow See other posts from Stack Overflow or by Mannaz
Published on 2010-04-08T08:12:45Z Indexed on 2010/04/08 10:23 UTC
Read the original article Hit count: 341

Filed under:

android

|

java

|

exception

|

observer

|

thread

I have an Observable and an Observer. The observable does download some stuff in a background thread and calls notifyObservers to let the observers read the status.

At some point in public void update the observer tries to updates the GUI

((TextView)findViewById('R.id.foo')).setText("bar");

but it seems like the observable thread calls this method, because the Observable (!!!) throws this:

 android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
 at android.view.ViewRoot.checkThread(ViewRoot.java:2462)
 at android.view.ViewRoot.requestLayout(ViewRoot.java:512)
 ...
 at com.mynamespace.acitivty.TrackActivity.startPlay(TrackActivity.java:72)
 at com.mynamespace.acitivty.TrackActivity.update(TrackActivity.java:107)
 at java.util.Observable.notifyObservers(Observable.java:147)
 at java.util.Observable.notifyObservers(Observable.java:128)
 at com.mynamespace.module.communication.Download.stateChanged(Download.java:213)
 at com.mynamespace.module.communication.Download.run(Download.java:186)
 at java.lang.Thread.run(Thread.java:1058)

Is there some way I can prevent this from happening? I'm sure I'm missing something obvious here.

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