在iOS 11里众羡，在導(dǎo)航欄直接設(shè)置searchbar為titleView慈参，由于searchbar本身的圓角效果暴匠，會(huì)導(dǎo)致searchbar的高度變的比設(shè)計(jì)的要大蔚携，進(jìn)而導(dǎo)致navigationbar的高度也發(fā)生變化精耐，不再是最初的44.
可以使用下面的方法來解決這個(gè)問題：
UIView *titleView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 200, 32)];
UISearchBar *searchBar = [[UISearchBar alloc] initWithFrame:titleView.bounds];
searchBar.placeholder = @"搜索";
searchBar.searchBarStyle = UISearchBarStyleMinimal;
[titleView addSubview:searchBar];
self.navigationItem.titleView = titleView;
