Detect Start and Stop Editing UITextView

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名媛妹妹
名媛妹妹 2021-02-06 22:39

How can I call some code upon entering a UITextView (user taps to edit it) and leaving the view (user taps to leave it)?

Appreciate any help.

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  • 2021-02-06 23:18
    txtviewaddress.text="Address"
    
    txtViewAddress.TextColor = UIColor.LightGray;
    txtViewAddress.ShouldBeginEditing += (textView) =>
            {
     txtViewAddress.Text = "";
                txtViewAddress.TextColor = UIColor.Black;
                return true;
    };
    txtViewAddress.ShouldEndEditing += (textView) =>
            {
                if (textView.Text == "")
                {
                    txtViewAddress.Text = " Address";
                    txtViewAddress.TextColor = UIColor.LightGray;
    
                }
                return true;
            };
    
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  • 2021-02-06 23:26

    http://developer.apple.com/library/ios/#documentation/uikit/reference/UITextViewDelegate_Protocol/Reference/UITextViewDelegate.html#//apple_ref/occ/intf/UITextViewDelegate

    Here you can find several useful methods to investigate:

    • textViewDidBeginEditing:
    • textViewDidEndEditing:

    Moreover to live UITextView you often should implement action that calls [yourTextView resignFirstResponder];

    Objective-C example

    //you may specify UITextViewDelegate protocol in .h file interface, but it's better not to expose it if not necessary
    @interface ExampleViewController()<UITextViewDelegate> 
    
    @end
    
    @implementation ExampleViewController
    
    - (void)viewDidLoad {
        [super viewDidLoad];
    
        //assuming _textView is already instantiated and added to its superview
        _textView.delegate = self;
    }
    
    
    //it's nice to separate delegate methods with pragmas but it's up to your local code style policy
    #pragma mark UITextViewDelegate
    
    - (void)textViewDidBeginEditing:(UITextView *)textView {
        //handle user taps text view to type text
    }
    
    - (void)textViewDidEndEditing:(UITextView *)textView {
        //handle text editing finished    
    }
    
    @end
    

    Swift Example

    class TextViewEventsViewController: UIViewController, UITextViewDelegate {
    
        @IBOutlet weak var exampleTextView: UITextView!
    
        override func viewDidLoad() {
            super.viewDidLoad()
    
            self.exampleTextView.delegate = self
        }
    
        func textViewDidBeginEditing(_ textView: UITextView) {
            print("exampleTextView: BEGIN EDIT")
        }
    
        func textViewDidEndEditing(_ textView: UITextView) {
            print("exampleTextView: END EDIT")
        }
    }
    
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  • 2021-02-06 23:32

    You could also implement the UITextViewDidChange delegate methods. I use the code below in my app for taking quick notes. Whenever the user has entered a character, the observer catches this from the notification center and calls the saveText method.

    Here's how:

    Add this line to the viewDidLoad method:

    [NSNotificationCenter.defaultCenter addObserver:self selector:@selector(textViewDidChange:) name:UITextViewTextDidChangeNotification object:nil];
    

    and these lines at the appropriate place in your code (like in the section that handles the text view delegate methods. TIP: Use pragma marks for this (#pragma mark - TextView Delegate Methods):

    - (void)textViewDidChange:(UITextView *)textView{
    
        NSLog(@"textViewShouldEndEditing"); // Detect in log output if the method gets called
        [self saveText:nil]; // Call any method you like
    
    }
    
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  • 2021-02-06 23:42

    use the delegate and use:

    - (void) textViewDidBeginEditing:(UITextView *) textView {
        // Your code here
    }
    
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