Up navigation examples are hard to find

[LeafyLappa]

It seems that all examples for "up" back arrow navigation are in the "legacy-architecture-samples". A bit hard to find especially as they are "legacy" and written in java.

By up navigation I mean this:

simple-stack/samples/legacy-architecture-samples/simple-stack-example-mvvm-fragments/src/main/java/com/zhuinden/simplestackexamplemvvm/application/BaseKey.java

Line 65 in 842bfc7

public abstract boolean shouldShowUp();

[Zhuinden]

Heyo, it's primarily because the icon being "back" is typically encoded in either the screen itself, or can be evaluated with shouldBeUpArrow = stateChange.getNewKeys().size > 1 in the SimpleStateChanger.

But I haven't worked on app with a design that actually shares the toolbar across the entire app in a very long time, which is why you only saw that in the legacy example.

The title scared me for half a sec because goUp() and goUpChain() really aren't really used anywhere in any samples, even if the support is there.

[LeafyLappa]

Ahh, I see. I'm so used to Jetpack Navigation where up arrow seems to be handled via magic (once you call something like setupActionBarWithNavController) I did not realize I should simply put a toolbar in my fragments or main activity and define the navigation behavior myself, wew

shouldBeUpArrow = stateChange.getNewKeys().size > 1

It would be nice however to have something like a TLDR or recipes page for things like this.

[Zhuinden]

Technically it does exist in this sample:

simple-stack/tutorials/tutorial-sample/src/main/java/com/zhuinden/simplestacktutorials/steps/step_3/Step3Activity.kt

Line 52 in 528fb85

binding.step3TitleButtonBack.showIf { newKeys.size > 1 } // show up if can go back

but I'll try to think of a way

[Zhuinden]

Relevant #287