Can I replicate programmatically what a tap on the UIStatusBar does w/ UISearchController?

Question

I can't find a way to scroll a UIScrollView to the top in the same way the UIStatusBar does when the UINavigationItem contains a UISearchController. In that case, the scroll view scrolls to the top including showing the search bar. If I try to do this with the usual suspects (calling scroll, setting the content offset, etc.), I can't seem to make the search bar appearing.

Can I replicate programmatically what a tap on the UIStatusBar does?

Answer 1

In my opinion, I think Apple uses private API here to make it. But if you want to replicate something look like it, make the search bar appearing. You can follow step:

• Scroll UIScrollView to top

  self.scrollView.contentOffset = CGPointZero;
  

• After that, show search bar and large title

  // Show large title
  self.navigationItem.hidesSearchBarWhenScrolling = NO;
  // Show search bar
  self.navigationItem.largeTitleDisplayMode = UINavigationItemLargeTitleDisplayModeAlways;
  

• When search bar and large title are displayed, reset navigationItem properties to give scrollView normal behavior

  self.navigationItem.hidesSearchBarWhenScrolling = YES;
  self.navigationItem.largeTitleDisplayMode = UINavigationItemLargeTitleDisplayModeAutomatic;
  

Result:

Working code:

[UIView animateWithDuration:0.25f animations:^{
  self.scrollView.contentOffset = CGPointZero;
} completion:^(BOOL finished) {
  [UIView animateWithDuration:0.25f animations:^{
    self.navigationItem.hidesSearchBarWhenScrolling = NO;
    self.navigationItem.largeTitleDisplayMode = UINavigationItemLargeTitleDisplayModeAlways;
  } completion:^(BOOL finished) {
    self.navigationItem.hidesSearchBarWhenScrolling = YES;
    self.navigationItem.largeTitleDisplayMode = UINavigationItemLargeTitleDisplayModeAutomatic;
  }];
}];

For more detail, you can take a look at my demo repo.