Summary:
I wrote up a bunch of context for this in response to #27038 by fat. That comment is reproduced here in this commit message. You can see it in it's original contxt here: https://github.com/facebook/react-native/pull/27038
Okay, here is what I think is happening. For context, here is a diagram I have of how focus and blur propagates through the system. This might be interesting to refer back to as you go through the rest of my explanation.
ScrollView's scrollResponder is responsible for blurring text inputs when a touch occurs in the ScrollView but outside of the currently focused TextInput. The code for that is here:
https://github.com/facebook/react-native/blob/6ba2769f0f92ca75fb0eb60ccb8337920a9c31eb/Libraries/Components/ScrollResponder.js#L301-L314
This happens on `scrollResponderHandleResponderRelease` aka, touch up.
It checks for what the currently focused textinput is by calling `TextInputState.currentlyFocusedField()`.
That function is a JS variable that is being updated by calls to `TextInputState.focusTextInput` and `TextInputState.blurTextInput`:
https://github.com/facebook/react-native/blob/6ba2769f0f92ca75fb0eb60ccb8337920a9c31eb/Libraries/Components/TextInput/TextInputState.js#L36-L71
I added some console logs to those methods to see which ones are being called when running your repro (thanks for the repro!). **This is without your fix**
Click on and off:
```
// Click on input 1
focusTextInput input1
TextInput's _onFocus called
// Click on blank space
scrollResponderHandleResponderRelease blur input1
blurTextInput input1
TextInput's _onBlur called
```
Click on input1, then input 2, then off
```
// Click on input 1
focusTextInput input1
TextInput's _onFocus called for input1
// Click on input 2
focusTextInput input2
TextInput's _onBlur called for input1
TextInput's _onFocus called for input2
// Click on blank space
scrollResponderHandleResponderRelease blur input2
blurTextInput input2
TextInput's _onBlur called for input2
```
And now for the bug. Click on input 1, tab to 2, then off
```
// Click on input 1
focusTextInput input1
TextInput's _onFocus called for input1
// Tab to input 2
TextInput's _onBlur called for input1
TextInput's _onFocus called for input2
// Click on blank space
scrollResponderHandleResponderRelease blur input1
blurTextInput input1
```
Notice how `focusTextInput` was never called with input2 in the last example. Since this is the function that sets the `currentlyFocusedField` when we click on the blank space RN is trying to blur the first input instead of the second.
# The root cause
We are tracking the state of which field is focused in JS which has to stay in sync with what native knows is focused. We [listen to _onPress](https://github.com/facebook/react-native/blob/6ba2769f0f92ca75fb0eb60ccb8337920a9c31eb/Libraries/Components/TextInput/TextInput.js#L1103-L1107) and call `TextInputState.focusTextInput` in that handler. However, we don't currently have anything listening to other ways for an input to become focused (like tabbing) so it doesn't end up updating the `currentlyFocusedField`.
We have the same problem with blur that we actually fixed the same way you did here in this PR:
https://github.com/facebook/react-native/blob/6ba2769f0f92ca75fb0eb60ccb8337920a9c31eb/Libraries/Components/TextInput/TextInput.js#L1182-L1189
If you look back at my diagram at the beginning of this post, you'll notice the missing edge from `TextInput._onFocus` to `TextInputState.focusTextInput`. That's the problem. :)
The reason this solution works is because this function **is** the notification from native that an input was focused or blurred. This solution is *fine* because this updates the `currentlyFocusedID` but isn't great because it both sets that value and **calls the native code to focus or blur again**. Luckily the native code doesn't send an event back to JS if you try to blur an already blurred TextInput otherwise we'd have an infinite loop.
# The correct solution
The correct thing would probably be to have all of this tracking in native code and not in JavaScript code. That's a pretty big change though and very out of scope. Something for our team to keep in mind for the future.
A short term term solution would be to refactor `focusTextInput` and `blurTextInput` to pull out the part that sets the `currentlyFocusedID` that we could call from `TextInput` directly from `_onFocus` and `_onBlur`.
# ^This short term term solution is what this commit is doing.
Changelog:
[General][Changed] TextInput no longer does an extra round trip to native on focus/blur
Reviewed By: RSNara
Differential Revision: D18278359
fbshipit-source-id: 417566f25075a847b0f4bac2888f92fbac934096
Summary:
We are going to need to change some of these APIs to use refs instead of findNodeHandle. I figured I'd start by adding some tests
Changelog:
[Internal] Adding tests for TextInput
Reviewed By: yungsters
Differential Revision: D17892806
fbshipit-source-id: f59ff99fa4d064239f171acb64a8441e07bb71c1
Summary:
This is the next step in moving RN towards standard path-based requires. All the requires in `Libraries` have been rewritten to use relative requires with a few exceptions, namely, `vendor` and `Renderer/oss` since those need to be changed upstream. This commit uses relative requires instead of `react-native/...` so that if Facebook were to stop syncing out certain folders and therefore remove code from the react-native package, internal code at Facebook would not need to change.
See the umbrella issue at https://github.com/facebook/react-native/issues/24316 for more detail.
[General] [Changed] - Migrate "Libraries" from Haste to standard path-based requires
Pull Request resolved: https://github.com/facebook/react-native/pull/24749
Differential Revision: D15258017
Pulled By: cpojer
fbshipit-source-id: a1f480ea36c05c659b6f37c8f02f6f9216d5a323
Summary:
Currently calling native methods on internal react native components throw a warning. I believe this is problematic because _users_ aren't calling native methods on internal components, the _component_ is making the call.
So for instance, if I unmount a component that has a form with a few uses of `TextInput`, which is a perfectly valid test case, my test output will be full of warnings that I can't call `.blur()` in the test renderer environment. That's very misleading, because I didn't, the internal component did. In fact, as far as I can tell, there's not really even anything I can do to stop that call or use the output from it, its all internal. `TextInput` is a black box, and 99% of users writing tests probably won't even know it calls `.blur()` under the hood on unmount.
I want to change these to `jest.fn()` because I think this eliminates a lot of chatter in test output, but also doesn't send users down a rabbit hole of trying to find workarounds that may involve filtering console output, which could potentially lead them to inadvertently filter out real warnings that they should see.
So I'm willing to change the implementation of how I did this, but I don't think its right to warn users that they called a native method when they didn't. If they build a component that calls these methods, I believe it's on them to do something similar to this, and maybe we can make this exposed as a helper that can be used for third party component mocks?
[General] [Changes] - Changed MockNativeMethods for core components to `jest.fn()` instead of function that warns about calling native methods.
Pull Request resolved: https://github.com/facebook/react-native/pull/24337
Differential Revision: D14822126
Pulled By: cpojer
fbshipit-source-id: 2199b8c8da8e289d38823bdcd2c43c82f3f635c9
Summary:
Back it out again. This time really not sure why this is breaking, but it seems to be production only. The error seems to be "RCTSinglelineTextInputView" was not found in the UIManager" but the relavent logic is not changed in this diff, just moved around, so unclear why it would trigger a failure.
Reverting to be safe. When we re-apply the diff, we'll need to test a full OTA to prod to verify the fix.
Reviewed By: blairvanderhoof
Differential Revision: D13108463
fbshipit-source-id: 5f877a0c1a08dc114ce45921d6d92bf619575977
Summary: D10515754 reapplied by backing out D12989604 and then fixed by manually forwarding the instance methods to the host function instead of using `forwardRef`. This also removes the need for the $flowFixMe.
Reviewed By: TheSavior
Differential Revision: D13048482
fbshipit-source-id: ff2447aff123e0960eddaef645f7dc976a426e14
Summary: Adds a basic test that would have prevented S168585. We should expand coverage of this and other components as well.
Reviewed By: TheSavior
Differential Revision: D13038064
fbshipit-source-id: 14cf4742efd53d7bca2a3f8d1c5c34ebc6227674
Eli White
James Ide
Brandon Carroll
Spencer Ahrens
