iOS 11 SearchBar in NavigationBar

You can change the height of UISearchBar in iOS 11 by adding a constraint of height 44:

if #available(iOS 11.0, *) {
    searchBar.heightAnchor.constraint(equalToConstant: 44.0).isActive = true
}

I was having the same issue and after a few day googling the issue, I found this page - https://translate.google.com/translate?hl=en&sl=zh-CN&u=http://www.jianshu.com/p/262f6e34a7d3&prev=search.

This page leads to this git repo - https://github.com/DreamTravelingLight/searchBarDemo - this demo project shows how to use the old way with titleView to still have a searchBar without the sizing issue.

The key lines are these

_searchBar = [self addSearchBarWithFrame:CGRectMake(0, 0, kScreenWidth - 2 * 44 - 2 * 15, 44)];
UIView *wrapView = [[UIView alloc] initWithFrame:_searchBar.frame];
[wrapView addSubview:_searchBar];
self.navigationItem.titleView = wrapView;

If you embed the UISearchBar inside a view, and set that wrapView as the titleView, the UISearchBar will have the size you set for it, and will fit the nav bar as intended.

Thanks, David

There's a new searchController property on navigationItem in iOS 11.

https://developer.apple.com/documentation/uikit/uinavigationitem/2897305-searchcontroller

Use like this...

if #available(iOS 11.0, *) {
     navigationItem.searchController = searchController
} else {
     // Fallback on earlier versions
     navigationItem.titleView = searchController?.searchBar
}

In Objective-C the if statement looks like this:

if (@available(iOS 11.0, *)) {

On iOS 11, if you don't set navigationItem.hidesSearchBarWhenScrolling = false, the search bar may initially be hidden, unless the user scrolls down to reveal it. If you do set it to false, it appears stacked below where the title would go without the user having to scroll.