UISearchController: show results even when search bar is empty

Question

As I understand, the default behaviour of UISearchController is:

1. On tapping search bar, background is dimmed and \'cancel\' button is shown.

Answer 1

With tricky things like this I recommend the sledge hammer approach! That is to detect when something tries to make it hidden and when it does, change it back. This can be done via KVO (Key Value Observing). This will work no matter what, without having to handle all the intricacies of the search bar. Sorry the code is complicated but KVO is an older style API but my code follows recommend practice. In your SearchResultsViewController put this:

static int kHidden;

@implementation SearchResultsViewController

-(void)viewDidLoad{
    [super viewDidLoad];
    [self.view addObserver:self
                   forKeyPath:@"hidden"
                      options:(NSKeyValueObservingOptionNew |
                               NSKeyValueObservingOptionOld)
                      context:&kHidden];
}

- (void)observeValueForKeyPath:(NSString *)keyPath
                      ofObject:(id)object
                        change:(NSDictionary *)change
                       context:(void *)context {
    // if it was our observation
    if(context == &kHidden){
        // if the view is hidden then make it visible.
        if([[change objectForKey:NSKeyValueChangeNewKey] boolValue]){
            self.view.hidden = NO;
        }
    }
    else{
        // if necessary, pass the method up the subclass hierarchy.
        if([super respondsToSelector:@selector(observeValueForKeyPath:ofObject:change:context:)]){
            [super observeValueForKeyPath:keyPath
                                 ofObject:object
                                   change:change
                                  context:context];
        }
    }
}

- (void)dealloc
{
    [self.view removeObserver:self forKeyPath:@"hidden"];
}

// Here have the rest of your code for the search results table.

@end

This works in all cases including if the text is cleared.

Lastly, to prevent the table doing an ugly fade to grey then to white when the search activates, use this:

self.searchController.dimsBackgroundDuringPresentation = NO;

Answer 2

I have tried PetahChristian solution, the preload result did show up when we first focus the searchbar, but when we enter something then clear it, the preload results will not reappear.

I came up with another solution. We only need to add a delegate into SearchResultsController and call it when our searchController.searchBar.text is empty. Something like this:

SearchResultsController:

protocol SearchResultsViewControllerDelegate {
   func reassureShowingList() -> Void
}

class FullSearchResultsViewController: UIViewController, UISearchResultsUpdating{
   var delegate: SearchResultsViewControllerDelegate?
   ...
   func updateSearchResultsForSearchController(searchController: UISearchController) {
    let query = searchController.searchBar.text?.trim()
    if query == nil || query!.isEmpty {
        ...
        self.delegate?.reassureShowingList()
        ...
    }
    ...
}

And in the controller contains the SearchController, we add our delegate:

self.searchResultsController.delegate = self
func reassureShowingList() {
    searchController.searchResultsController!.view.hidden = false
}

Answer 3

You can simply implement the UISearchResultsUpdating protocol and set the results controller view to always show in updateSearchResultsForSearchController:

 func updateSearchResultsForSearchController(searchController: UISearchController) {

   // Always show the search result controller
   searchController.searchResultsController?.view.hidden = false

   // Update your search results data and reload data
   ..
}

This works because the method is called even when the search bar is activated, without any text.

Answer 4

I really liked Simon Wang's answer and worked with it and this is what I did and it works perfectly:

I subclass the UISearchController in my custom class:

class CustomClass: UISearchController {
  override var searchResultsController: UIViewController? {
    get {
      let viewController = super.searchResultsController
      viewController?.view.isHidden = false
      return viewController
    }
    set {
      // nothing
    }
  }
}

Also make sure you don't have this anywhere in your code:

self.resultsSearchController.isActive = true

resultsSearchController is my UISearchController

Answer 5

Swift 4 version of malhals answer:

class SearchController: UISearchController {

    private var viewIsHiddenObserver: NSKeyValueObservation?

    override func viewDidLoad() {
        super.viewDidLoad()

        viewIsHiddenObserver = self.searchResultsController?.view.observe(\.hidden, changeHandler: { [weak self] (view, _) in
            guard let searchController = self else {return}
            if view.isHidden && searchController.searchBar.isFirstResponder {
            view.isHidden = false
            }
        })

    }

}

Please note the [weak self]. Otherwise you would introduce a retain cycle.

Answer 6

What is being hidden is the search results controller's view. Therefore it is sufficient to unhide it any time it might be hidden. Simply do as follows in the search results controller:

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    self.view.isHidden = false
}

func updateSearchResults(for searchController: UISearchController) {
    self.view.isHidden = false
    // ... your other code goes here ...
}

Now the results view (i.e. the table view) is always visible, even when the search bar text is empty.

By the way, the iOS Mail app behaves like this, and I assume that's how it's implemented (unless Apple has access to some secret private UISearchController setting).

[Tested in iOS 10 and iOS 11; I didn't test on any earlier system.]