Changing a TextView in another class from a Service

Question

I have two classes, one is a standard activity , the other a service . I would like the service to update a TextView (via .setText() ) of the Activity on certain events that happen within the service.

I've tried to achieve this by programming something like a setter-method inside the Activity-Class, but TextViews don't accept a static -reference, and when I try invoking an instance of the Activity-class instead (via MyActivityClassName aVariable = new MyActivityClassName(); ), I get a NullPointer Exception , even though the View in questions is visible at the time of the call.

Could anyone tell me what I'm doing wrong :-)? It is probably more of a basic Java question than an Android-one, but since it might have to do with the nature of Android-services, I've still added the android-tag.

Thanks for your help!

Answer 1

I would like the service to update a TextView (via .setText) of the Activity on certain events that happen within the service.

I would strongly recommend greater logical decoupling. Have the Service tell the Activity to update the TextView .

You can do that via a broadcast Intent , or by having the Activity provide a listener object that the Service calls. In either case, be sure the Activity detaches from the service (unregisters the listener or broadcast Intent receiver), lest you cause a memory leak.

And, of course, this only works if the activity is actually running.