我在ViewController中有一个UITextView。我已经从UITextViewDelegate实现了shouldChangeTextInRange委托方法。我通过上述委托方法获得的用于删除单个字符的range值类似于{location,1}。
但是如果我在执行删除操作之前使用滑入式机制插入单词,则会删除整个单词,而不是单个字符。我需要对此进行跟踪。
例如,我使用幻灯片类型机制插入“ Hello”。如果按键盘上的Delete键,则会得到{4,1}作为范围,但是在文本视图中整个单词“ Hello”已被删除。在这种情况下,我需要将范围设置为{0,5},就像选择文本“ Hello”并删除它一样。
是否有办法区分普通删除操作和幻灯片到类型的删除操作?如何获得在文本视图中已删除的实际范围?
非常感谢您的帮助。
这是我尝试过的。
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
self.addTextView()
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
self.view.endEditing(true)
}
}
extension ViewController {
func addTextView() {
let textContainer = NSTextContainer(size: CGSize(width: 200, height: CGFloat.greatestFiniteMagnitude))
let layoutManager = NSLayoutManager()
layoutManager.addTextContainer(textContainer)
let textStorage = NSTextStorage()
textStorage.delegate = self
textStorage.addLayoutManager(layoutManager)
let textViewFrame = CGRect(x: 50, y: 50, width: 200, height: 200)
let textView = UITextView(frame: textViewFrame, textContainer: textContainer)
textView.backgroundColor = .green
textView.delegate = self
self.view.addSubview(textView)
}
}
extension ViewController: UITextViewDelegate {
func textViewDidBeginEditing(_ textView: UITextView) {
print("text editing began")
}
func textViewDidChange(_ textView: UITextView) {
print("text view content changed")
}
func textViewDidChangeSelection(_ textView: UITextView) {
print("text view selection changed")
}
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
print("should change \(text) in \(range)")
return true
}
func textViewDidEndEditing(_ textView: UITextView) {
print("text editing ended")
}
}
extension ViewController: NSTextStorageDelegate {
func textStorage(_ textStorage: NSTextStorage, willProcessEditing editedMask: NSTextStorage.EditActions, range editedRange: NSRange, changeInLength delta: Int) {
print("will process \(editedRange)")
}
func textStorage(_ textStorage: NSTextStorage, didProcessEditing editedMask: NSTextStorage.EditActions, range editedRange: NSRange, changeInLength delta: Int) {
print("did process \(editedRange)")
}
}
编辑1:
我有一个独立的存储机制,我可以根据该存储机制根据shouldChangeText委托方法中提供的范围和替换文本来更新对文本视图的更改。为了简单起见,我没有将其包括在内。
我只是注意到了完全相同的一件事,并且努力了好一阵子,试图以一种优雅的方式解决这个问题。在我看来,这必须是一个错误,因此希望它将尽快得到解决。提交提出的解决方案后,我将向Apple提交错误报告。
// Variable to keep track of when a word might have been deleted
fileprivate var didJustDelete = false
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
if text.count > 0 {
// Code to handle adding text
...
} else {
// Code to handle deleting text
didJustDelete = true
...
}
}
func textViewDidChange(_ textView: UITextView) {
// Check for deleting an entire word
if didJustDelete {
didJustDelete = false
let difference = actualText.count - textView.text.count
if difference > 0 {
// Code to handle deleting a word
let range = NSRange(location: textView.text.count, length: difference)
...
}
}
}