how to know when text is pasted into UITextView

Question

What event is fired when a block of text is pasted into a UITextView? I need to modify the frame of my textView when the text is pasted in.

Thanks for reading.

Answer 1

Here is what i use to detect paste events in UITextView:

 // Set this class to be the delegate of the UITextView. Now when a user will paste a text in that textview, this delegate will be called.
-(BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text {

    // Here we check if the replacement text is equal to the string we are currently holding in the paste board
    if ([text isEqualToString:[UIPasteboard generalPasteboard].string]) {

        // code to execute in case user is using paste

    } else {

        // code to execute other wise
    }

    return YES;
}

Answer 2

Checking the pasteboard's string by if string == UIPasteboard.general.string takes a couple of seconds if you have long sentence in the pasteboard. The user sees the keypad is frozen while this check. My solution is to check if the length of new characters is longer than 1. If it is longer than 1, the string is from the pasteboard.

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        if string.characters.count > 1{
            //User did copy & paste

        }else{
            //User did input by keypad
        }            
         return true
 }

Answer 3

Your UITextView will call its UITextViewDelegate method

 - (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text

if a delegate has been set up. This gets called both when a character is typed on the keyboard, and when text is pasted into the text view. The text pasted in is the replacementText argument.

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

Answer 4

This is working Perfect in

Xcode 11x Swift 5x

 func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
    if text.contains(UIPasteboard.general.string ?? "") {
        return false
    }
    return true
}

When ever the user try to Paste into text field the if condition will execute
This code will stop pasting

Answer 5

It is for Swift5.1

func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
    if let paste = UIPasteboard.general.string, text == paste {
       print("paste")
    } else {
       print("normal typing")
    }
    return true
}

Answer 6

try subclasses UITextview,and override this function.

public override func paste(_ sender: Any?) 

Answer 7

In iOS 14 there is notification which is triggered every time when application gets value from UIPasteboard.general.string
So the proper way of detect if user pasted something is overriding paste(_) function:

var isPastingContent = false

open override func paste(_ sender: Any?) {
    isPastingContent = true
    super.paste(sender)
}

func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
    if isPastingContent {
         // do something
    }
    isPastingContent = false
}

Answer 8

carlos16196 was a good approach, but I would also tweak it by changing [text isEqualToString:[UIPasteboard generalPasteboard].string] to [text containsString:[UIPasteboard generalPasteboard].string]

By doing this, you will detect when user pastes in the textview after other typed text that is not in the UIPasteboard.

This is the code:

-(BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text {

// Here we check if the replacement text is equal to the string we are currently holding in the paste board
if ([text containsString:[UIPasteboard generalPasteboard].string]) {

    // code to execute in case user is using paste

} else {

    // code to execute other wise
}

return YES;
}

Answer 9

iOS 13 with Combine

public extension UITextView {
    var textDidChangePublisher: AnyPublisher<String, Never> {
        NotificationCenter.default
            .publisher(for: UITextView.textDidChangeNotification, object: self)
            .compactMap { $0.object as? UITextView }
            .compactMap(\.text)
            .eraseToAnyPublisher()
    }
    
    var attributedTextDidChangePublisher: AnyPublisher<NSAttributedString, Never> {
        NotificationCenter.default
            .publisher(for: UITextView.textDidChangeNotification, object: self)
            .compactMap { $0.object as? UITextView }
            .compactMap(\.attributedText)
            .eraseToAnyPublisher()
    }
}

var cancellable = Set<AnyCancellable>()

textView.textDidChangePublisher
    .removeDuplicates()
    .sink { [weak self] newValue in
        guard let self = self else { return }
        // what you want
    }
    .store(in: &cancellable)

Answer 10

This is what I use to detect pasted images:

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
    if (UIPasteboard.generalPasteboard.image &&
        [UIPasteboard.generalPasteboard.string.lowercaseString isEqualToString:text.lowercaseString]) {

       //Pasted image

        return NO;
    }

    return YES;
}

Answer 11

This is the only way that I was able to get it to work. I used a textField but the same concept should still work for a textView.

In the shouldChangeCharactersIn delegate method below I casted the string argument to a NSString, then back to a String. Then I compared it to whatever was pasted. Everything else is in the comments above the code.

// 1. class property for anything that was copied and will be pasted
var pasted: String?

// 2. When the user first taps the textfield set the above class property to the copied text (if there is any)
func textFieldDidBeginEditing(_ textField: UITextField) {

    // 3. set it here
    pasted = UIPasteboard.general.string // this is what was copied and will be pasted
}

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {

    guard let safeText = textField.text else { return true }

    let currentString: NSString = safeText as NSString
    let newString: NSString = currentString.replacingCharacters(in: range, with: string) as NSString

    let str = newString as String

    // 4. compare the above str constant to the pasted variable
    if str == self.pasted {
        print("pasted")

    } else {

        print("typed")
    }

    return true
}

func textFieldDidEndEditing(_ textField: UITextField) {

    // 5. when the user is finished with the textField set the pasted property to nil
    pasted = nil
}

Answer 12

In SWIFT 4:

func textViewDidChange(_ textView: UITextView) {

    if(textView.text == UIPasteboard.general.string)
    {
        //Text pasted
    }
}