hi.

hello, gonzobrains!

Sorry I am late.

that's OK -- do you have a quick question?

Yes.

I am having trouble with fragments remaining on the screen after resuming an app that was paused. If the user tries to use them it causes the app to crash. In one case I manage to call the fragment's Dismiss() when the Activity's OnPause() is called. This works for that particular case, but often times OnPause() doesn't get called.

So now I have to troubleshoot both these "ghost" fragments and why OnPause() isn't getting called in the first place. Any ideas?

nothing leaps to mind

all attached fragments should get the same lifecycle events as their enclosing activity

that's what I thought.

if you are not getting lifecycle events, perhaps the fragment is no longer attached

I think that may be the case.

in terms of "remaining on the screen", perhaps there is something in how the fragment sets up the UI, where it goes behind the activity's back (e.g., directly adds widgets to containers)

I will look into that. I inherited this code so I am not completely familiar with the design.

ah

for example, make sure that if it inflates a layout, it uses the three-parameter inflate() method, and passes false for the third parameter

The design relies on a single activity which just displays fragments for each thing the app needs to do.

and certain fragments display yet another fragment that acts as a drop-down.

I haven't seen that drop-down technique used before

at the fragment level, that is

if that dropdown is displayed when the user puts the phone to sleep, it will still be displayed when the app resumes despite its "parent" fragment having gone away already.

yeah, me neither.

I think it is basically a listview within a fragment. and an edit text to search within it.

there may be something screwy with how that drop-down is being implemented, but it's tough for me to say exactly how it is going haywire

on one screen, I can call that "drop down" fragment's Dismiss() when the parent fragment's OnPause() is called. That cures it. But for some reason not all screen fragments get their OnPause() called for some reason.

add some logging to onAttach()/onDetach() and see what turns up

ahh, okay.

and see how the drop-down fragment is doing its UI

I logged all the OnPause/OnStop/OnDestroy methods but not attach/detach.

i will see if I can this.Dismiss() the drop-down fragment on OnDestroy

dismiss() is the sort of thing that I associate with a DialogFragment, but if you're using a DialogFragment for a drop-down, it may be trying to do some fancy footwork to arrange to display the drop-down window in the right spot

i'm sorry I meant OnDetach()

and it may be that the "fancy footwork" has bugs

yes, I believe the drop-down is derived from DialogFragment

there are lots of expandable-view libraries on the Android Arsenal

you might wind up switching to one of those, rather than trying to have a DialogFragment serve in that role

anyway, that's a wrap for today's chat

yeah that's a good idea.

the transcript will be posted to https://commonsware.com/office-hours/ in a bit

thanks.

ok thanks again.

you're welcome!

the next chat is tomorrow at 7:30pm US Eastern

have a pleasant day!

you, too!