Summary: Hi, This PR Solves this issue #3083. This PR solves the problem of default color on TabBar being always grey. Which looks great if the barTintColor is unchanged. However if we set the barTintColor to something else (like blue in example) text and icons become quite unreadable.  Commit (c206417) - Enable setting color of unselected tabs Solves this issue with a prop (unselectedTintColor) on TabBarIOS to which you just pass a color like you can for barTintColor and tintColor. This leaves us with a result that is on second picture. Notice the color of text on tabs.  Or change it to yellow for demonstrating purposes  for Building React Native installed.
Start an Android emulator (Genymotion is recommended).
cd react-native
./gradlew :Examples:UIExplorer:android:app:installDebug
./packager/packager.sh
Note: Building for the first time can take a while.
Open the UIExplorer 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 uiexplorer
buck install -r uiexplorer
./packager/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).