[Android] fix: screen height wrong. Not catering correctly for action bar

[hboon]

No description provided.

[hboon]

Shucks. Hold this, please. Might have introduced a bug.

[hboon]

Done!

This approach isn't quite so efficient because whenever show_bar() or hide_bar() is called, we update the heights of every screen (fragment) in the navigation stack and re-layout them. We can probably have a flag to defer to re-layout, haven't added it for simplicity. I can't figure out a more elegant way though.

Someone review this? :)

[lrz]

Looks good. I would suggest to cache the result in UI::Navigation.bar_height as this may be called multiple times and the value seems to be constant.

[hboon]

Hmm.. I suppose the bar height might change if the user changes their theme? (but that will probably break this code anyway so maybe that doesn't matter...). Will follow soon with a commit.

[hboon]

Bar height now cached.