iOS UITextField resignFirstResponder on viewWillDisappear

Question

I have an application with two simple screen. The first screen always opens same instance of the second screen. The second screen has a text field and a button to manually hide keyboard.

The resignFirstResponder on viewWillDisappear is not working.

Case 1:

Click openSearchButton on the main screen.
SearchViewController is opened.
Click text field.
Keyboard becomes visible.
Click back button.
Application returns to the first screen.
Click openSearchButton on the main screen.
(iOS 10.2) Screen is completely white for a short time.
SearchViewController is opened.
The text field becomes first responder and keyboard becomes visible.

Case 2:

Click openSearchButton on the main screen.
SearchViewController is opened.
Click text field.
Keyboard becomes visible.
Click hideKeyboardButton
Keyboard becomes hidden.
Click back button.
Application returns to the first screen.
Click openSearchButton on the main screen.
SearchViewController is opened.

Code:

         @implementation MainViewController
        -(void) viewDidLoad {
            [super viewDidLoad];
            UIStoryboard *sb = [UIStoryboardWithName:@"Main" bundle:nil];
            self.searchView = (SearchViewController*) [sb instantiateViewControllerWithIdentifier:@"searchView"];
        }

        - (IBAction)openSearchButtonClicked:(id)sender{
            [self.navigationController pushViewController:self.searchView animated:YES];
        }
        @end

        @implementation SearchViewController
        - (void)viewWillDisappear:(BOOL)animated{
            assert(self.searchTextField != nil);    
            [self.searchTextField resignFirstResponder];
            [super viewWillDisappear:animated];
        } 

        - (IBAction)hideKeyboardButtonClicked:(id)sender{
            [self.searchTextField resignFirstResponder];
        }
        @end

Is your (IBAction)hideKeyboardButtonClicked is working properly? — Chanchal Warde, Jan 25 '17 at 08:06
@ChanWarde Yes. If I click hideKeyboardButton before clicking back button, keyboard is hidden. It remains hidden after re-opening searchView. — fthdgn, Jan 25 '17 at 08:09
Why don't you try call this method on back button action then navigate to previous screen. — Chanchal Warde, Jan 25 '17 at 08:11
Back button is default back button of navigation controller. I have to implement a custom back button. — fthdgn, Jan 25 '17 at 08:13
Ok , then provide your code then i will be able to help. There must be something missing. — Chanchal Warde, Jan 25 '17 at 08:15
My all code is this. I created an empty storyboard project with a navigation controller and two view controller. Then connected searchTextField and button action methods. — fthdgn, Jan 25 '17 at 08:18
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/133956/discussion-between-chanwarde-and-fthdgn). — Chanchal Warde, Jan 25 '17 at 08:22

fthdgn · Answer 1 · 2017-01-25T09:20:05.300

I have solved the problem with a workaround. I checked stack trace of textFieldDidBeginEditing after re-opening searchView. Somehow UIKit decides to call becomeFirstResponder on text field.

My solution is this: not allow text field to be first responder until the view controller appeared. However flashing white screen still occurs on iOS 10.2.

- (void)viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];
    self.allowToBecomeFirstResponser = YES;
}
- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField{
    return self.allowToBecomeFirstResponser ;
}
- (void)viewWillDisappear:(BOOL)animated{
    self.allowToBecomeFirstResponser = NO;
    [super viewWillDisappear:animated];
}     

0 ??? 0x000000011d54d91c 0x0 + 4787067164, 
1 DEMO 0x000000010c24d880 main + 0, 
2 UIKit 0x000000010d60a227 -[UITextField _becomeFirstResponder] + 481, 
3 UIKit 0x000000010d04d28d -[UIResponder becomeFirstResponder] + 324, 
4 UIKit 0x000000010cf42e03 -[UIView(Hierarchy) becomeFirstResponder] + 99, 
5 UIKit 0x000000010d609ad7 -[UITextField becomeFirstResponder] + 51, 
6 UIKit 0x000000010cf42e3b -[UIView(Hierarchy) deferredBecomeFirstResponder] + 49, 
7 UIKit 0x000000010cf43144 __45-[UIView(Hierarchy) _postMovedFromSuperview:]_block_invoke + 175, 
8 UIKit 0x000000010cf43086 -[UIView(Hierarchy) _postMovedFromSuperview:] + 437, 
9 UIKit 0x000000010cf4cf4b -[UIView(Internal) _addSubview:positioned:relativeTo:] + 1604, 
10 UIKit 0x000000010cecf392 -[_UIParallaxDimmingView didMoveToWindow] + 123, 
11 UIKit 0x000000010cf4a9a0 -[UIView(Internal) _didMoveFromWindow:toWindow:] + 1482, 
12 UIKit 0x000000010cf4a68e -[UIView(Internal) _didMoveFromWindow:toWindow:] + 696, 
13 UIKit 0x000000010cf43112 __45-[UIView(Hierarchy) _postMovedFromSuperview:]_block_invoke + 125, 
14 UIKit 0x000000010cf43086 -[UIView(Hierarchy) _postMovedFromSuperview:] + 437, 
15 UIKit 0x000000010cf4cf4b -[UIView(Internal) _addSubview:positioned:relativeTo:] + 1604, 
16 UIKit 0x000000010cecbc38 __53-[_UINavigationParallaxTransition animateTransition:]_block_invoke + 2101, 
17 UIKit 0x000000010cf475ce +[UIView(Animation) performWithoutAnimation:] + 65, 
18 UIKit 0x000000010cecb072 -[_UINavigationParallaxTransition animateTransition:] + 1225, 
19 UIKit 0x000000010d01fe6c -[UINavigationController _startCustomTransition:] + 3038, 
20 UIKit 0x000000010d02b3fe -[UINavigationController _startDeferredTransitionIfNeeded:] + 386, 
21 UIKit 0x000000010d02bf47 -[UINavigationController __viewWillLayoutSubviews] + 43, 
22 UIKit 0x000000010d171509 -[UILayoutContainerView layoutSubviews] + 202,

zero3nna · Answer 2 · 2017-01-25T08:42:43.463

0

 -(BOOL) textFieldShouldReturn: (UITextField *) textField
 {
    [textField resignFirstResponder];
    return YES;
 }

But you need to add the UITextFieldDelegate to your SearchViewController to make -(BOOL) textFieldShouldReturn: work in there.

edited Jan 25 '17 at 08:42

answered Jan 25 '17 at 08:36

zero3nna

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iOS UITextField resignFirstResponder on viewWillDisappear

2 Answers2