How can you intercept pasting into a NSTextView to remove unsupported formatting?

Question

I\'m trying to create a simple NSTextView-based window for simple WYSIWYG editing. However, I only want to allow certain types of formatting (e.g. Bold, Italic, Underline a

Answer 1

[Edit: see Joshua Nozzi's comment!]

One possible solution would be to make your NSTextView implement this template method:

- (void)paste:(id)sender {
    NSPasteboard *pb = [NSPasteboard generalPasteboard];
    //receive formatted string from pasteboard
    //remove formatting from string
    //put back plaintext string into pasteboard
    [super paste:sender];
    //put back initial formatted string
}

This way you don't have to handle any of the actual insertion/pasting but can mess with the pasteboard before the actual pasting.

You might also want to look into these methods of NSTextView dealing with the Pasteboard:

• preferredPasteboardTypeFromArray:restrictedToTypesFromArray:
• readSelectionFromPasteboard:
• readSelectionFromPasteboard:type:
• readablePasteboardTypes
• writablePasteboardTypes
• writeSelectionToPasteboard:type:
• writeSelectionToPasteboard:types:
• validRequestorForSendType:returnType:

Answer 2

In your NSTextView subclass:

  override func paste(_ sender: Any?) {
     pasteAsPlainText(sender)
  }