fix missing lines in the ios picker

[adnanbabar]

Hi,

Just opening this issues again this is a case where the picker is missing the highlight lines for the currently selected picker item.

http://stackoverflow.com/questions/39564660/uipickerview-selection-indicator-not-visible-in-ios10

Issue was raised here as well
#14442

Fixed was proposed in another issue(link below) but it was never merged.
#13342

Additional Information
"react-native": "0.53.3",
Platform: iOS 10.2
Development Operating System: macOS

Thanks
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[yangtaufoo]

I’m having this issue too. It’s completely missing after upgrading from RN0.51.

React Native 0.53.3 & 0.53.0
Platform: iOS 11.2

[adnanbabar]

Okay, I will try my best to provide more information.

React native 0.53.3 on
Mac OSX 10.13.1.
Simulator 11.3

After adding a picker component first time to the screen I can see the "separator lines" the minute I interact and reload simulator the lines disappear. After this even if I restart the whole app by running "react-native run-ios" command I don't see the separator lines. Screenshot link below
https://raw.githubusercontent.com/louietan/PickerIOSIssue/master/demo.png

Reproduction steps:

1. Add Picker component with some values
2. Interact with picker
3. And reload ios simulator by cmd+R
4. Separator lines disappear at this point.

Again issues have already been raised twice below

Issue was raised here as well
#14442

Fixed was proposed in another issue(link below) but it was never merged.
#13342

Please let me know if you need anymore information

[adnanbabar]

@hramos Any update on this, please?

[hramos]

I don't have anything to add, other than making sure you fill in the template in your original post and to provide sample code that reproduces the issue.

[react-native-bot]

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[yangtaufoo]

@hramos Can i know the rationale for the dispatch action in setSelectedIndex in RCTPicker.m?

Running on,
react-native: 0.54.2
react: 16.3.0-alpha.1
ios: 11.2

I have the missing picker lines issue and it seems that modifying from,

dispatch_async(dispatch_get_main_queue(), ^{
      [self selectRow:selectedIndex inComponent:0 animated:animated];
});

to this,

[self selectRow:selectedIndex inComponent:0 animated:animated];

(i.e. removing the dispatch_async) will allow for the lines to show

Other ways to make it show,
• Launching a modal and immediately closing it when the picker is shown
• Putting the picker in a modal