Steps to Reproduce

Hey,

I have a TextField with keyboardType: TextInputType.number. I tested this on a galaxy s8 running android 7.0 and it works fine.

On a galaxy note 4 running android 6.0.1, the keyboard only has numbers, there are no decimal separators or the negative symbol.

Flutter Doctor

[✓] Flutter (on Mac OS X 10.13.2 17C88, locale en, channel master)
[✓] Android toolchain - develop for Android devices (Android SDK 27.0.1)
[✓] iOS toolchain - develop for iOS devices (Xcode 9.2)
[✓] Android Studio
[✓] IntelliJ IDEA Community Edition (version 2017.3.4)
[✓] Connected devices

• No issues found!