void updateAdapter(PagerAdapter oldAdapter, PagerAdapter newAdapter) {
if (oldAdapter != null) {
oldAdapter.unregisterDataSetObserver(mPageListener);
}
if (newAdapter != null) {
newAdapter.registerDataSetObserver(mPageListener);
}
if (mPager != null) {
mLastKnownCurrentPage = -1;
mLastKnownPositionOffset = -1;
updateText(mPager.getCurrentItem(), newAdapter);
requestLayout();
}
}
