@TargetApi(Build.VERSION_CODES.LOLLIPOP)
private void toolbarSetElevation(float elevation) {
// setElevation() only works on Lollipop
if (AndroidUtils.isLollipop()) {
tToolbar.setElevation(elevation);
}
}
@TargetApi(Build.VERSION_CODES.LOLLIPOP)
@Override
protected void onSaveInstanceState(Bundle outState) {
if (AndroidUtils.isLollipop()) {
outState.putFloat(STATE_TOOLBAR_ELEVATION, tToolbar.getElevation());
}
outState.putFloat(STATE_TOOLBAR_TRANSLATION_Y, tToolbar.getTranslationY());
outState.putInt(STATE_VERTICAL_OFFSET, verticalOffset);
outState.putInt(STATE_SCROLLING_OFFSET, scrollingOffset);
outState.putParcelable(STATE_RECYCLER_VIEW, rvCities.getLayoutManager().onSaveInstanceState());
super.onSaveInstanceState(outState);
}
@TargetApi(Build.VERSION_CODES.LOLLIPOP)
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
// Assign Toolbar to the activity
tToolbar = (Toolbar) findViewById(R.id.tToolbar);
setSupportActionBar(tToolbar);
getSupportActionBar().setTitle(R.string.app_name);
// RecyclerView with sample data
rvCities = (RecyclerView) findViewById(R.id.rvCities);
rvCities.setLayoutManager(new LinearLayoutManager(this));
rvCities.setAdapter(new CitiesAdapter(CityUtils.CITIES));
if (savedInstanceState != null) {
if (AndroidUtils.isLollipop()) {
tToolbar.setElevation(savedInstanceState.getFloat(STATE_TOOLBAR_ELEVATION));
}
tToolbar.setTranslationY(savedInstanceState.getFloat(STATE_TOOLBAR_TRANSLATION_Y));
verticalOffset = savedInstanceState.getInt(STATE_VERTICAL_OFFSET);
scrollingOffset = savedInstanceState.getInt(STATE_SCROLLING_OFFSET);
rvCities
.getLayoutManager()
.onRestoreInstanceState(savedInstanceState.getParcelable(STATE_RECYCLER_VIEW));
}
// We need to detect scrolling changes in the RecyclerView
rvCities.addOnScrollListener(
new RecyclerView.OnScrollListener() {
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
if (newState == RecyclerView.SCROLL_STATE_IDLE) {
if (scrollingOffset > 0) {
if (verticalOffset > tToolbar.getHeight()) {
toolbarAnimateHide();
} else {
toolbarAnimateShow(verticalOffset);
}
} else if (scrollingOffset < 0) {
if (tToolbar.getTranslationY() < tToolbar.getHeight() * -0.6
&& verticalOffset > tToolbar.getHeight()) {
toolbarAnimateHide();
} else {
toolbarAnimateShow(verticalOffset);
}
}
}
}
@Override
public final void onScrolled(RecyclerView recyclerView, int dx, int dy) {
verticalOffset = rvCities.computeVerticalScrollOffset();
scrollingOffset = dy;
int toolbarYOffset = (int) (dy - tToolbar.getTranslationY());
tToolbar.animate().cancel();
if (scrollingOffset > 0) {
if (toolbarYOffset < tToolbar.getHeight()) {
if (verticalOffset > tToolbar.getHeight()) {
toolbarSetElevation(TOOLBAR_ELEVATION);
}
tToolbar.setTranslationY(-toolbarYOffset);
} else {
toolbarSetElevation(0);
tToolbar.setTranslationY(-tToolbar.getHeight());
}
} else if (scrollingOffset < 0) {
if (toolbarYOffset < 0) {
if (verticalOffset <= 0) {
toolbarSetElevation(0);
}
tToolbar.setTranslationY(0);
} else {
if (verticalOffset > tToolbar.getHeight()) {
toolbarSetElevation(TOOLBAR_ELEVATION);
}
tToolbar.setTranslationY(-toolbarYOffset);
}
}
}
});
}