Issue 1:
Description

Shifting BottomNavigationBar widgets don't seem to be rendering properly:

If you manually set the type to fixed, it looks the way it should. At first, I thought it was because I had too many items in the bar, but it also doesn't work with just two. I also tried setting the fixedColor property on the bar, and the backgroundColor properties on the items themselves, but it doesn't change the outcome. I'm not that experienced with Flutter (I've just been playing with it for the last few days), but I'd love to try submitting a PR to fix this if someone could help me out.

For reference, here's the code:

import 'package:flutter/material.dart';

void main() => runApp(new App());

class App extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new MaterialApp(
title: 'Tab Bar Test',
theme: new ThemeData(primarySwatch: Colors.blue),
home: new Scaffold(
appBar: new AppBar(title: new Text('Flutter Issue')),
bottomNavigationBar: new BottomNavigationBar(
type: BottomNavigationBarType.fixed,
items: [
new BottomNavigationBarItem(
icon: new Icon(Icons.favorite),
title: new Text('FAVORITES')
),
new BottomNavigationBarItem(
icon: new Icon(Icons.people),
title: new Text('CONTACTS')
),
new BottomNavigationBarItem(
icon: new Icon(Icons.phone),
title: new Text('PHONE')
),
new BottomNavigationBarItem(
icon: new Icon(Icons.voicemail),
title: new Text('VOICEMAIL')
)
]
),
)
);
}
}

Steps to Reproduce

Run the attached code on an iPhone running iOS 11.2.6.

Observe the incorrect appearance of the BottomNavigationBar.

Logs

flutter run:

Launching lib/main.dart on Pranjal's iPhone in debug mode...
Found saved certificate choice "***". To clear, use "flutter config".
Signing iOS app for device deployment using developer identity: "***"
Running Xcode clean... 1.7s
Starting Xcode build...
├─Building Dart code... 7.1s
├─Assembling Flutter resources... 6.5s
└─Compiling, linking and signing... 8.8s
Xcode build done 24.4s
Installing and launching... 12.6s
Syncing files to device Pranjal's iPhone... 3.4s

🔥 To hot reload your app on the fly, press "r". To restart the app entirely, press "R".
An Observatory debugger and profiler on Pranjal's iPhone is available at: http://127.0.0.1:8101/
For a more detailed help message, press "h". To quit, press "q".

flutter analyze:

No issues found!
Ran in 5.6s

Flutter Doctor

[✓] Flutter (Channel beta, v0.1.5, on Mac OS X 10.13.3 17D102, locale en-US)
• Flutter version 0.1.5 at /Users/pranjalsatija/flutter
• Framework revision 3ea4d06340 (13 days ago), 2018-02-22 11:12:39 -0800
• Engine revision ead227f118
• Dart version 2.0.0-dev.28.0.flutter-0b4f01f759

[✓] Android toolchain - develop for Android devices (Android SDK 27.0.3)
• Android SDK at /Users/pranjalsatija/Library/Android/sdk
• Android NDK location not configured (optional; useful for native profiling support)
• Platform android-27, build-tools 27.0.3
• Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-915-b08)

[✓] iOS toolchain - develop for iOS devices (Xcode 9.2)
• Xcode at /Applications/Xcode.app/Contents/Developer
• Xcode 9.2, Build version 9C40b
• ios-deploy 1.9.2
• CocoaPods version 1.3.1

[✓] Android Studio (version 3.0)
• Android Studio at /Applications/Android Studio.app/Contents
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-915-b08)

[✓] IntelliJ IDEA Ultimate Edition (version 2017.2.6)
• Flutter plugin version 21.2.2
• Dart plugin version 172.4343.25

[✓] Connected devices (1 available)
• Pranjal's iPhone • XXX • ios • iOS 11.2.6

• No issues found!

Issue 2:
Steps to Reproduce

When adding more than 3 items in a BottomNavigationBar, all items turn white, and are unreadable on the light-gray background. Also, the active item is also white, and not the provided fixedColor. A minimal code sample can be found here

Also see the following images:

Logs

N/A

Flutter Doctor

[✓] Flutter (on Mac OS X 10.13.1 17B1003, locale nl-NL, channel alpha)
• Flutter at /Users/dirk/Developer/flutter/sdk
• Framework revision 8f65fec5f5 (5 days ago), 2017-12-12 09:50:14 -0800
• Engine revision edaecdc8b8
• Tools Dart version 1.25.0-dev.11.0
• Engine Dart version 2.0.0-edge.d8ae797298c3a6cf8dc9f4558707bd2672224d3e

[✓] Android toolchain - develop for Android devices (Android SDK 26.0.0)
• Android SDK at /Users/dirk/Library/Android/sdk
• Android NDK location not configured (optional; useful for native profiling support)
• Platform android-26, build-tools 26.0.0
• Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 1.8.0_112-release-b06)

[-] iOS toolchain - develop for iOS devices (Xcode 9.2)
• Xcode at /Applications/Xcode.app/Contents/Developer
• Xcode 9.2, Build version 9C40b
✗ libimobiledevice and ideviceinstaller are not installed. To install, run:
brew install --HEAD libimobiledevice
brew install ideviceinstaller
✗ ios-deploy not installed. To install:
brew install ios-deploy
• CocoaPods version 1.2.0

[✓] Android Studio (version 2.3)
• Android Studio at /Applications/Android Studio.app/Contents
• Java version OpenJDK Runtime Environment (build 1.8.0_112-release-b06)

[✓] IntelliJ IDEA Ultimate Edition (version 2017.3)
• Flutter plugin version 20.0.3
• Dart plugin version 173.3727.108

[✓] Connected devices
• iPhone X • 9500EA8E-1292-4223-BFFF-1B2134D5C47C • ios • iOS 11.2 (simulator)