Add SegmentedControlIOS

[clayallsopp]

Fixes#534:

<SegmentedControlIOStintColor="#ff0000"values={["One","Two","Three","Four"]}selectedValue={"One"}momentary={false}disabled={false}onValueChange={(value)=>console.log(value)}/>

This only supports string-based segments, not images. Also doesn't support full customization (no separator images etc); I figure this is a good MVP to lock-down a basic API

I also included a snapshot test case, but the images keep coming out funky. When I look at the sim, I see that the text labels show up for the selected segment, but the snapshot keeps coming out with no text on those segments. I tried forcing a delay, but same result. Is that explainable?

Obviously happy to change anything about the API, code-style nitpicks, etc

[a2]

Nit: Remove extra line.

[a2]

Clay, this looks great. I only have a few nit requests but if you can make those edits, we can merge this straightaway. 😃

[ashwinb]

Hm, we should ideally just use selectedIndex in the backing implementation, and expose both selectedValue and selectedIndex to the user. Or just avoid selectedValue completely. It just seems like a bad idea that typos there will result in undefined behavior.

[a2]

@ashwinb Good idea. I like that better. The user should be able to set the selectedIndex and values separately.

[clayallsopp]

@a2@ashwinb I went back and forth on this; I figured that, on the JS side, people would be doing the index -> value conversion on every callback to make their logic not dependent on ordering, so we might as well do it for them. I.e.:

_onSegmentValueChanged : (value) =>
// this is resilient to ordering changes
switch(value) {
case "Profile":
break;
}

vs

_onSegmentValueChanged : (selectedIndex) =>
value = this.props.segments[selectedIndex]
// now it is resilient to order changes
switch() {
}

maybe a compromise is to 1) allow selectedValue and selectedSegmentIndex as props, and prefer selectedIndex if given 2) pass both selectedSegmentIndex and selectedValue in the callback event, for raw onChange listeners, but keep onValueChange returning the segment value for the case above

but my opinion isn't terribly strong, so will defer to your judgement

[ashwinb]

Yes, passing both (index, value) seems like a good idea in the callback, although I am fine even with just (value) as you have done. However, what I am opposed to is the selectedValue prop -- that is an unnecessary landmine of typos (unless, of course, you make it an enum, etc. if you are using something like flowtype). We should just avoid it if possible.

[clayallsopp]

I've updated the PR; check out the API examples

[vjeux]

It doesn't patch cleanly anymore, can you rebase? Sorry about this

[clayallsopp]

@vjeux done, np

[jozan]

What's the status of this?

[jozan]

Needs RCT_EXPORT_MODULE(); to work in current version.

[nicklockwood]

Hey, sorry about the radio silence on this. The internal diff sort of got lost in transmission for a while, however the good news is that this has now been merged and will ship with the next release.

[clayallsopp]

Lovely, thanks!