iOS 11 search bar jumping to top of screen

问题

I've got a UITableView in which I set its header to be a search bar.

tableView.tableHeaderView = searchController.searchBar

Everything works according to plan until you click it and it seemingly detaches from the tableView and jumps to the top of the screen. The tableView rows stay in place. Any reason it would do that in iOS 11 and not iOS 10?

回答1:

It is encouraged to apply the new way to show search bar/search controller on iOS 11. Here is what I have done:

    if #available(iOS 11.0, *) {
        navigationItem.searchController = searchController
    } else {
        tableView.tableHeaderView = searchController.searchBar
    }

回答2:

My first post on SO, i hope i am doing this right.

I had the exact same problem and really struggled with finding a solution. But now i have managed to fix it by subclassing UISearchController.

This subclass has two properties:

var customDelegate : CustomSearchControllerDelegate!
var searchBarWithCustomSize : UISearchBar!

So instead of using the searchBar of UISearchController i can now use the new property searchBarWithCustomSize from my custom searchController, like this:

tableView.tableHeaderView = customSearchController.searchBarWithCustomSize

This makes the searchbar behave correctly when active. You also have more freedom with this searchBarWithCustomSize, for example you can change its frame if needed and so on.

In my implementation i need the delegate to know when the searchbar textfield has been changed but i guess the usage of a delegate is dependent on your situation.

回答3:

I had the exact same issue - weird jumping behaviour of the UISearchBar on iOS11, where on iOS10 everything is fine.

Regarding the advice by Simon Wang above - the problem I had there is that I am not defining my UISearchBar inside a UIViewController, I am instead inside another UITableViewCell - so therefore I don't have access to the navigationItem and can't present my search bar that way.

Anyway, after much trial and error, the only way I could get things working was to scrape the UISearchController and related delegates altogether.

Instead I define a UISearchBar inside Interface Builder, and define its layout constraints as appropriate. I then make its parent class conform to UISearchBarDelegate and do searchBar.delegate = self

I then add a bunch of delegate methods to catch content changes to the search bar, and update my table results accordingly:

func searchBarTextDidBeginEditing(_ searchBar: UISearchBar) {  
   filterContentForSearchText(self.searchBar.text!)
}

func searchBarTextDidEndEditing(_ searchBar: UISearchBar) {
   filterContentForSearchText(self.searchBar.text!)
   self.searchBar.resignFirstResponder()
}

func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
   filterContentForSearchText(self.searchBar.text!)
}

And life is good again. Hope this helps!

回答4:

Try this:

if (@available(iOS 11, *)){
    [searchVC.searchBar addObserver:self forKeyPath:@"frame" options: NSKeyValueObservingOptionNew context:nil];
}else{
    [view addSubview:searchVC.searchBar];
}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    CGRect rect = [change[@"new"] CGRectValue];
    if (rect.origin.y == 14) {
        CGRect temp = rect;
        temp.origin.y = 20;
        [self.searchVC.searchBar setValue:@(temp) forKey:@"frame"];
    }else if (rect.size.height == 56){
        CGRect temp = rect;
        temp.size.height = 50;
        [self.searchVC.searchBar setValue:@(temp) forKey:@"frame"];
    }
}

回答5:

Try this.

if #available(iOS 11.0, *) {
    searchBar.heightAnchor.constraint(equalToConstant: 44).isActive = true
}

来源：https://stackoverflow.com/questions/45798923/ios-11-search-bar-jumping-to-top-of-screen

标签

ios

uitableview

ios11

swift4