The current approach is hard to maintain, for example the last key
"autofill" was not displayed.
This implements a PreferenceGroup that contains the check boxes for
every extra keys without involving listing the preferences in
settings.xml.
A custom layout is used to remove the 'title' text view.
The list of extra keys is moved into the new class.
'ExtraKeyCheckBoxPreference' becomes a nested class.
This activity points to the system settings page for enabling input
methods. This is purely a shortcut but is expected by many users.
It could be made more useful in the future or hidden whenever the
keyboard is enabled.
Add a "Theme" option to choose between a dark and light theme.
The light theme uses the colors of the dark theme with the luminance
inversed.
The reloading after a configuration change is changed slightly:
- Special handling is needed when the Theme is changed (recreate the views)
- The default implementation of 'onConfigurationChanged' is used
Which triggers more refresh (but don't recreate the views)
- 'onCreateInputView' is no longer needed
