ㅆㅂ 존나 더럽게 detect해야되네

contentView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {

Rect r = new Rect();
contentView.getWindowVisibleDisplayFrame(r);
int screenHeight = contentView.getRootView().getHeight();

// r.bottom is the position above soft keypad or device button.
// if keypad is shown, the r.bottom is smaller than that before.
int keypadHeight = screenHeight - r.bottom;

Log.d(TAG, "keypadHeight = " keypadHeight);

if (keypadHeight > screenHeight * 0.15) { // 0.15 ratio is perhaps enough to determine keypad height.
// keyboard is opened
}
else {
// keyboard is closed
}
}
});