Capitalize first letter of a text in track selector menu items

[moneytoo]

This is how the audio selector of StyledPlayerView looks like in two languages (English and Czech):

In Czech (and other languages probably as well), the language name (angličtina) is in all lower case characters. But because of the use in this menu, I think the first letter should be upper cased in DefaultTrackNameProvider.buildLanguageOrLabelString().

• ExoPlayer version number: 2.15.0
• Android version: Android 10
• Android device: OnePlus 7

[krocard]

This is the string returned by Local.getDisplayName, I'm not sure we want to do any transformation on it. The characters returned might not even have a upper case concept. @ojw28 you are marked as UI owner in our triage guide, so assigning to you as minor.

[ojw28]

I think Locale.getDisplayName returns a string that would be suitable for use mid-sentence. In English, language names are generally capitalized whether they occur at the start or in the middle of a sentence, so it makes no difference. I'm guessing this is not the case in Czech, which is why this ends up being problematic. We probably want to use UCharacter.toTitleCase to convert the string into a suitable title case before returning it.

[moneytoo]

Locale names are "title cased" at least in the platform Settings app. This is what it uses internally: https://android.googlesource.com/platform/frameworks/base.git/+/refs/tags/android-11.0.0_r45/core/java/com/android/internal/app/LocaleHelper.java#68

[ojw28]

Thanks for the pointer!

[ojw28]

This is fixed by the three commits ref'd above (the second is a rollback, and third is a roll forward that includes a fix for the initial commit).