Paste Formatted Text, Not Images or HTML

Question

I am trying to emulate the pasteboard behavior of the iOS Pages and Keynote apps. In short, allowing basic NSAttributedString text formatting (i.e. BIU) to be pasted into a

Answer 1

Some copy/paste goodies and ideas, for you :)

// Setup code in overridden UITextView.copy/paste
let pb = UIPasteboard.generalPasteboard()
let selectedRange = self.selectedRange
let selectedText = self.attributedText.attributedSubstringFromRange(selectedRange)

// UTI List
let utf8StringType = "public.utf8-plain-text"
let rtfdStringType = "com.apple.flat-rtfd"
let myType = "com.my-domain.my-type"

• Override UITextView copy: and use your custom pasteboard type pb.setValue(selectedText.string, forPasteboardType: myType)

• To allow rich text copy (in copy:):

  // Try custom copy
  do {
      // Convert attributedString to rtfd data
      let fullRange = NSRange(location: 0, length: selectedText.string.characters.count)
      let data:NSData? = try selectedText.dataFromRange(fullRange, documentAttributes: [NSDocumentTypeDocumentAttribute: NSRTFDTextDocumentType])
      if let data = data {
  
          // Set pasteboard values (rtfd and plain text fallback)
          pb.items = [[rtfdStringType: data], [utf8StringType: selectedText.string]]
  
          return
      }
  } catch { print("Couldn't copy") }
  
  // If custom copy not available;
  // Copy as usual
  super.copy(sender)
  

• To allow rich text paste (in paste:):

  // Custom handling for rtfd type pasteboard data
  if let data = pb.dataForPasteboardType(rtfdStringType) {
      do {
  
          // Convert rtfd data to attributedString
          let attStr = try NSAttributedString(data: data, options: [NSDocumentTypeDocumentAttribute: NSRTFDTextDocumentType], documentAttributes: nil)
  
          // Bonus: Possibly strip all unwanted attributes here.
  
          // Insert it into textview
          replaceSelection(attStr)
  
          return
      } catch {print("Couldn't convert pasted rtfd")}
  }
  // Default handling otherwise (plain-text)
  else { super.paste(sender) }
  

• Even better then using a custom pasteboard type, white-list all possibly wanted tags, loop through and strip away all other on paste.

• (Bonus: help UX in other apps by stripping away unnecessary attributes you've added, on copy (like font and fg-color))

• Also worth noting, the textView might not want to allow pasting when the pasteboard contains a specific type, to fix that:

  // Allow all sort of paste (might want to use a white list to check pb.items agains here)
  override func canPerformAction(action: Selector, withSender sender: AnyObject?) -> Bool {
      if action == #selector(UITextView.paste(_:)) {
          return true
      }
      return super.canPerformAction(action, withSender: sender)
  }
  

• Furthermore, cut: could be nice to implement as well. Basically just copy: and replaceSelection(emptyString)

• For your convenience:

  // Helper to insert attributed text at current selection/cursor position
  func replaceSelection(attributedString: NSAttributedString) {
      var selectedRange = self.selectedRange
  
      let m = NSMutableAttributedString(attributedString: self.attributedText)
      m.replaceCharactersInRange(self.selectedRange, withAttributedString: attributedString)
  
      selectedRange.location += attributedString.string.characters.count
      selectedRange.length = 0
  
      self.attributedText = m
      self.selectedRange = selectedRange
  }
  

Good luck!

Refs: Uniform Type Identifiers Reference

Answer 2

This should be a comment on Leonard Pauli's answer, but I don't have enough reputation to make comments yet.

Instead of:

selectedRange.location += attributedString.string.characters.count 

(or attributedString.string.count as it is in more recent versions of Swift)

It's best to use:

selectedRange.location += attributedString.length

Otherwise when you paste text that contains emoji that cause attributedString.length and attributedString.string.count to differ, the selection will end up in the wrong place.