If application root is reinitialized, update ActionSheet and Toast refs

[fredmon3]

This PR is related to issues #1397, #1315, #937.

There is potential that React Native may unmount and remount the root node of the application due to Android lifecycle events without clearing the JS execution environment. (This is possible even if native-base's Root is the top level component.) This results in actionSheetInstance being invalid as it pointed to the previously mounted application root's ActionSheet component that was unmounted.

This pull request updates the static actionSheetInstance and toastInstance refs regardless of what state they are in such that stale refs will be overwritten appropriately.

According to the React Ref documentation:

React will call the ref callback with the DOM element when the component mounts, and call it with null when it unmounts.

Thus, there is a null check on c in the ref callbacks.

[nachofregeiro]

Will this pull request be approved soon to fix both ActionSheet and Toast issues?

[fredmon3]

If there's any additional information that I can provide to assist with this pull request, please let me know. Thank you!

[SunburtReynolds]

Is there an ETA on this PR?

[adamawang]

+1

[akemys]

+1

[NappyPirate]

+1

[galo2002]

+1

[akhil-ga]

Fixes #1397 #937 #1121 #1895 #1790

[douglasjunior]

I think you don't need to check if c is valid. Just do the assignment.

[fredmon3]

Thanks for taking a look at this @douglasjunior. Does GeekyAnts have a preference on how to handle the case where c is null? @akhil-geekyants @SupriyaKalghatgi

[douglasjunior]

https://reactjs.org/docs/refs-and-the-dom.html#callback-refs

React will call the ref callback with the DOM element when the component mounts, and call it with null when it unmounts. ref callbacks are invoked before componentDidMount or componentDidUpdate lifecycle hooks.

I think if the component has been unmounted, you should not keep the ref. This is memory leak.

[schie]

@akhil-geekyants @douglasjunior @fredmon3 any updates?

[SupriyaKalghatgi]

This week 💯

[kstolte]

@SupriyaKalghatgi
will this be in the next release?

[gogulanareshkw]

"native-base": "^2.8.1",
"react": "^16.4.1",
"react-native": "^0.55.4",
please help me, am getting error as cannot read property 'showActionSheet' of null

to reproduce this issue follow these steps:

actionsheet available in page 1, for the first actionsheet is working
navigate to page 2 from page1, and then page 3 from page2 (page1 -> page2 -> page3)
then goback to page1 and click actionsheet, now getting error

[tapir]

Having the same issue as @gogulanareshkw.
Trying to show actionsheet twice after selecting an option triggers it