Optionally ignore @UIThread call when @EFragment is detached from Activity?

When using @Background in conjunction with @UIThread annotations on an @EFragment, it's possible that many developers don't want to run the method annotated with the @UIThread annotation if the Fragment is no longer attached to the activity. I think it would be great to add an annotation (something like @IgnoredWhenDetached) with the following rules:

Must also have the @UIThread annotation
Can only be used in conjunction with @EFragment classes
Simply wraps the @UIThreadmethod call in an if block like so

if(isAdded()) {
    //executable code
}

or

if(getActivity() != null) {
    //executable code
}

Here is a simple example and in my application I have dozens of things similar to this

@EFragment
public class LoaderFragment extends Fragment {

    @Background
    void longTask() {
        try {
            updateProgress(0);
            Thread.sleep(1000);
            updateProgress(50);
            Thread.sleep(1000);
            updateProgress(100);
        } catch (InterruptedException e) {
            killActivity()        
        }
    }

    @IgnoredWhenDetached
    @UiThread
    void updateProgress(int progress) {
        getActivity().setProgress(progress);
    }

    @IgnoredWhenDetached
    @UiThread
    void killActivity(int progress) {
        getActivity().finish();
    }

This essentially prevents the two @UIThread methods from getting a NPE if the Fragment were to have been destroyed at any point during the execution of the @Background method. While I realize this is something that can be easily guarded against by a simple null check, it makes the code much cleaner and is a very common use case in conjunction with Fragments. I would be more than happy to submit a pull request pending thoughts/comments about this. This could also be useful in conjunction with @Background on an @EFragment as well, but not a very common use case.

Vince

Actually #823 proposed the same, but it was rejected.

I read his actually before posting this. This is slightly different in that I'm not proposing making it the default behavior of @UIThread for @EFragment classes.

Yes, you are right.

Yeah, I prefer this solution as the developer still have the choice to handle theses cases as he want.
This may be in 3.1 :)

I tought about the API, and bringed up a version which uses a parameter in the @UiThread and not a new annotation. But i changed my mind since this feature is only for Fragments, @UiThread API should not be affected.
I think you can start to implement this if you want. :)

I think we could use this annotation even on methods which are not annotated with @UIThread or @Background.

I think you may be right. I'll look at doing another pull request then let the authors decide which, if any, they would like to merge.

@yDelouis

@yDelouis > Good idea 👍

This is an extremely good idea!
I'm currently using

if(isAdded()) {
    //executable code
}

in order to avoid the problem when switching really fast through fragments. An annotation like that makes total sense.

@yDelouis

Merged. Thanks to @yDelouis and @vincentjames501 for this

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Optionally ignore @UIThread call when @EFragment is detached from Activity? #875

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Optionally ignore @UIThread call when @EFragment is detached from Activity? #875

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WonderCsabo commented on Jan 11, 2014

vincentjames501 commented on Jan 11, 2014

WonderCsabo commented on Jan 11, 2014

DayS commented on Jan 11, 2014

WonderCsabo commented on Jan 13, 2014

yDelouis commented on Jan 13, 2014

vincentjames501 commented on Jan 13, 2014

DayS commented on Jan 13, 2014

toshe commented on May 17, 2014

DayS commented on Jun 8, 2014

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