When using the sliding spacebar language switch on ICS, both
LatinIME.toggleLanguage() and
InputMethodService.onCurrentInputMethodSubtypeChanged() invoke
LatinIME.onRefreshKeyboard(). This change eliminates the first one if
it isn't necessary.
This change also cleans up the followings.
* reuse theme Context when the keyboard theme hasn't been changed.
* clear the Keyboard cache when theme has been switched.
* eliminates unnecessary Context reference from LatinKeyboard and
SlidingLocaleDrawable.
* recycle Bitmap and reuse Canvas in KeyboardView.
Bug: 4725930
Change-Id: I87366e9304879d94d12b7345adea768d86d43519
Previously the key preview was implemented by PopupWindow. The key
preview popup window would be dismissed and shown each time the key
was released and pressed. It turned out that it was taking several
milliseconds.
This change implements the key preview by a simple TextView which will
be layout-ed at absolute coordinates within the screen FrameLayout.
And dismissing and showing the key preview is implemented by the
TextView's visibility.
This implementation needs careful coordination of candidates.xml
layout and LatinIME.onComputeInsets to control suggestion strip
visibility.
Bug: 4179964
Change-Id: Id6347cb35b91eb14ab20dd2f312e58b54b6625a7
