Android Hardware Back press required twice

[HarshulSharma000]

Description-
Inside any of the streams to go to previous screen by hardware back press, it is required to be pressed twice. Thus it seems like first back key press is being ignored. And after that app navigates to first screen(home) of main tab navigator. Instead if it should keep the progress of previous tab navigator.

Platform: Android 6
Steps to Reproduce:-

1. Go to the streams tab of main tab navigator.
2. Enter into any of the streams
3. Press Android hardware back key.

[HarshulSharma000]

I would like to work over this @borisyankov @gnprice @jainkuniya

[borisyankov]

Sure you can work on that. In fact, this is an important bug to fix fast.
This is likely an issue with React Navigation (though some chance it is with our code). I noticed it too.
@jainkuniya did you fix the previous similar bug? If so, can you remind me and @HarshulSharma000 what was the issue?

[jainkuniya]

Yup! I fixed the previous similar bug.
My previous commit 2a3e821

Actually each navigation in react-navigation (drawer, tabs, stack navigation) have their own implementation of handling back button press. Now the question is: when you press button it should be captured by which component.

On Current master if you observe carefully you will notice that:
for e.g.:
if you are on setting tab and open lets say Switch Account page, and then press button, you requires two back button press. First one is captured by MainTabs (HomeTabs) and 2nd one by stack navigation (which is responsible for going back). (Another version of this one: If you are on All Stream tab and then switch to Setting tabs and then Switch Account. In this case 3 press are required. One for MainTabs, one for StreamTabs and one for StackNavigation)

react-navigation/react-navigation#3200
I proposed react-navigation to add optional prop so that we can handle Back button as they want. But the better solution which I got from them is to override their implementation, the way I have done in my commit.

@HarshulSharma000 think logically at which level we need to override it. Feel free to reach me if you face any problem. Also claim issue by commenting @zulipbot claim.

[HarshulSharma000]

@zulipbot claim

[zulipbot]

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[jainkuniya]

@zulipbot label "help wanted"

[jainkuniya]

@HarshulSharma000 Now you can claim

[HarshulSharma000]

@zulipbot claim

[zulipbot]

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[HarshulSharma000]

@jainkuniya We can also try screen wise custom back behaviour as described in- https://reactnavigation.org/docs/custom-android-back-button-handling.html

[pulkonet]

It is not an issue on Android 8.0.0. Can't reproduce it.

[borisyankov]

It likely is not dependent on platform version so you probably just missed it 😄

[HarshulSharma000]

@borisyankov I think I have found the problem please check mobile channel.

[pulkonet]

@borisyankov Checked it again. It goes back in a single press. Not sure why this might be happening.

[borisyankov]

Fixed by #2180