react-native/RNTester
Moti Zilberman 5898817fc1 Implement letterSpacing on Android >= 5.0
Summary:
`letterSpacing` is completely missing from RN Android at the moment.

I've reviewed the `letterSpacing` implementations in #13199, #13877 and #16801 (that all seem to have stalled) and managed to put together an improved one based on #13199, updated to merge cleanly post 6114f863c3, that resolves the [issues](https://github.com/facebook/react-native/pull/13199#issuecomment-354568863) I've identified with that code.

I believe this is the closest PR yet to a correct implementation of this feature, with a few caveats:

- As with the other PRs, this only works on Android >= 5.0 (silently falling back to no letter spacing on older versions). Is this acceptable for a RN feature, in general? Would a dev mode warning be desirable?
- The other PRs seem to have explored the space of potential solutions to the layout issue ([Android renders space _around_ glyphs](https://issuetracker.google.com/issues/37079859), iOS to the _right_ of each one) and come up empty, so I've opted to merely document the difference.
- I have neither updated nor tested the "Flat" UI implementation - everything compiles but I've taken [this comment](https://github.com/facebook/react-native/issues/12770#issuecomment-294052694) to mean there's no point in trying to wade through it on my own right now; I'm happy to tackle it if given some pointers.
- The implementation in `ReactEditText` is only there to handle the placeholder text, as `ReactBaseTextShadowNode` already affects the input control's contents correctly.
  - I'm not sure whether `<TextInput>` is meant to respect `allowFontScaling`; I've taken my cue here from `ReactTextInputManager.setFontSize()`, and used the same units (SP) to interpret the value in `ReactEditText.setLetterSpacingPt()`.
  - I'm not sure whether `<TextInput>` is even meant to support `letterSpacing` - it doesn't actually work on iOS. I'm not going to be able to handle the Objective-C side of this, not as part of this PR at least.
- I have not added unit tests to `ReactTextTest` - is this desirable? I see that some other props such as `lineHeight` aren't covered there (unless I'm not looking in the right place).
- Overall, I'm new to this codebase, so it's likely I've missed something not mentioned here.

Note comment re: unit tests above; RNTester screenshots follow.

| iOS (existing functionality, amended test) | Android (new functionality & test) |
| - | - |
| <img src=https://user-images.githubusercontent.com/2246565/34458459-c8d59498-edcb-11e7-8c8f-e7426f723886.png width=300> | <img src=https://user-images.githubusercontent.com/2246565/34458473-2a1ca368-edcc-11e7-9ce6-30c6d3a48660.png width=300> |

| iOS _(not implemented, test not in this branch)_ | Android (new functionality & test) |
| - | - |
| <img src=https://user-images.githubusercontent.com/2246565/34458481-6c60a36e-edcc-11e7-9af5-9734dd722ced.png width=300> | <img src=https://user-images.githubusercontent.com/2246565/34458486-8b3cdcf8-edcc-11e7-974b-25c6085fa674.png width=300> |

| iOS _(not implemented, test not in this branch)_ | Android (new functionality & test) |
| - | - |
| <img src=https://user-images.githubusercontent.com/2246565/34458492-d69a77be-edcc-11e7-896f-21212621dbee.png width=300> | <img src=https://user-images.githubusercontent.com/2246565/34458490-b3a1139e-edcc-11e7-88c8-79d4430d1514.png width=300> |

https://github.com/facebook/react-native-website/pull/105 - this docs PR is edited slightly from what's in `TextStylePropTypes` here; happy to align either one to the other after a review.

[ANDROID] [FEATURE] [Text] - Implemented letterSpacing
Closes https://github.com/facebook/react-native/pull/17398

Reviewed By: mdvacca

Differential Revision: D6837718

Pulled By: hramos

fbshipit-source-id: 5c9d49e9cf4af6457b636416ce5fe15315aab72c
2018-02-27 14:53:58 -08:00
..
RNTester Update license headers for MIT license 2018-02-16 18:31:53 -08:00
RNTester-tvOS Re-license and rename UIExplorer integration test app as RNTester 2017-05-08 11:31:19 -07:00
RNTester.xcodeproj Reimagining of RCTShadowView layout API 2018-02-12 00:32:43 -08:00
RNTesterIntegrationTests Fixed problem in Text measurent on iOS 2018-02-25 09:37:38 -08:00
RNTesterUnitTests Update license headers for MIT license 2018-02-16 18:31:53 -08:00
android/app Update license headers for MIT license 2018-02-16 18:31:53 -08:00
js Implement letterSpacing on Android >= 5.0 2018-02-27 14:53:58 -08:00
README.md Move packager launcher scripts outside of `packager/` 2017-05-23 16:17:09 -07:00

README.md

RNTester

The RNTester showcases React Native views and modules.

Running this app

Before running the app, make sure you ran:

git clone https://github.com/facebook/react-native.git
cd react-native
npm install

Running on iOS

Mac OS and Xcode are required.

  • Open RNTester/RNTester.xcodeproj in Xcode
  • Hit the Run button

See Running on device if you want to use a physical device.

Running on Android

You'll need to have all the prerequisites (SDK, NDK) for Building React Native installed.

Start an Android emulator (Genymotion is recommended).

cd react-native
./gradlew :RNTester:android:app:installDebug
./scripts/packager.sh

Note: Building for the first time can take a while.

Open the RNTester app in your emulator.

See Running on Device in case you want to use a physical device.

Running with Buck

Follow the same setup as running with gradle.

Install Buck from here.

Run the following commands from the react-native folder:

./gradlew :ReactAndroid:packageReactNdkLibsForBuck
buck fetch rntester
buck install -r rntester
./scripts/packager.sh

Note: The native libs are still built using gradle. Full build with buck is coming soon(tm).

Built from source

Building the app on both iOS and Android means building the React Native framework from source. This way you're running the latest native and JS code the way you see it in your clone of the github repo.

This is different from apps created using react-native init which have a dependency on a specific version of React Native JS and native code, declared in a package.json file (and build.gradle for Android apps).