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Zhuinden / simple-stack

[ACTIVE] Simple Stack, a backstack library / navigation framework for simpler navigation and state management (for fragments, views, or whatevers).
Apache License 2.0
1.36k stars 76 forks source link

Transparent screens #193

Closed jamolkhon closed 5 years ago

jamolkhon commented 5 years ago

Sorry, couldn't come up with a better title.

Having screens A and B where B has transparent background. Will A be (partially) seen when B is the topmost screen?

If not what is the best way to accomplish this? I've started working on a new project where almost half of the screens should be or look like dialogs.

Zhuinden commented 5 years ago

I'd have to see the design to tell you something concrete (and I know that's not as easy to just show off 🤔 ) but as simple-stack handles the management of navigation state in the form of a list, technically what you do in the handleStateChange method is totally up to you -- you are not confined to the FragmentStateChanger nor the DefaultViewStateChanger.

The real trickery is the handling of [], [A,B,C] type of state changes, for example after process death or configuration changes. Because the views are destroyed and recreated by Android on configuration change, so if it needs to be "see-through", then in that case you'd have to restore the active screens in order after such recreation. Which you can, because you know exactly that [A,B,C] screens should be showing. So in such scenario, you would remove views only if its key is not in the stateChange.newKeys

I think this scenario is actually easier with simple-stack than it would be with any other navigation library available.

jamolkhon commented 5 years ago

profile-screen-or-dialog

This is how a typical see-through screen looks.

Zhuinden commented 5 years ago

I can imagine this as a [MapKey, MenuKey], just gotta make sure you add the MapKey to the screen it's in the new keys even if it's not the top (and not yet on the screen).

Zhuinden commented 5 years ago

Did that answer your question?

jamolkhon commented 5 years ago

Yes, it did. The solution was surprisingly easy. I just removed FragmentTransaction.detach calls then added a FragmentTransaction.add call for non-top keys as you suggested. Thanks for the help!

Zhuinden commented 5 years ago

(make sure to add fragments only if they are !isAdded 😉 )

Happy to hear!