NSTextView 在粘贴前修改字符串

Question

我的目标是在将字符串粘贴到 NSTextView 之前修改字符串 - 删除所有非字母（数字、空格等）。

通过这个link，我想出了以下代码：

override func paste(_ sender: Any?) {
    let pasteboard = NSPasteboard.general
 // receive string from pasteboard
    if let pasteboardString = pasteboard.string(forType: .string) {
        let lettersOnly = CharacterSet.letters

     // filter the incoming string
        let lettersOnlyString = String(pasteboardString.unicodeScalars.filter { lettersOnly.contains([=10=]) })

     // put back filtered string into pasteboard
        pasteboard.setString(lettersOnlyString, forType: .string)
        super.paste(sender)

     // put back initial formatted string
        pasteboard.setString(pasteboardString, forType: .string)
    }
}

lettersOnlyString确实是修改后的字符串，但最后还是粘贴了原字符串，我仍然看到所有非字母字符。

我在这里错过了什么，也许这不是要走的路？也许我需要为此覆盖另一种方法？

Answer 1

~~我想我找到了答案，我必须在 pasteboard.setString 之前添加 pasteboard.clearContents()。~~

为了完整起见，这是工作代码：

override func paste(_ sender: Any?) { let pasteboard = NSPasteboard.general // get string from pasteboard if let pasteboardString = pasteboard.string(forType: .string) { // remove formatting from string let lettersOnly = CharacterSet.letters let lettersOnlyString = String(pasteboardString.unicodeScalars.filter { lettersOnly.contains([=10=]) }) // put modified string on pasteboard pasteboard.clearContents() pasteboard.setString(lettersOnlyString, forType: .string) // paste string from pasteboard as plain text pasteAsPlainText(sender) // put original string back on pasteboard pasteboard.clearContents() pasteboard.setString(pasteboardString, forType: .string) } }

更新：

可以做得更简单：

override func paste(_: Any?) {
    let pasteboard = NSPasteboard.general
    guard let pasteboardString = pasteboard.string(forType: .string),
        let validatedInput = validateInput(pasteboardString)
    else { return }

    insertText(validatedInput, replacementRange: NSMakeRange(NSNotFound, 0))
}

其中 validateInput() 是过滤输入字符串的重构函数。

NSTextView 在粘贴前修改字符串

NSTextView modify string before pasting

macos

nstextview

nspasteboard