所以基本上我想在UITextView中添加一个无序列表。对于另一个UITextView我想添加一个有序列表。
我尝试使用此代码，但它仅在用户第一次按 Enter 后给了我一个项目符号，(仅此而已(，我什至无法退格。
- (void)textViewDidChange:(UITextView *)textView
{
if ([myTextField.text isEqualToString:@"n"]) {
NSString *bullet = @"u2022";
myTextField.text = [myTextField.text stringByAppendingString:bullet];
}
}
如果你只找到一种使用 Swift 执行它的方法，那么请随时发布代码的 Swift 版本。
问题是你正在使用
if ([myTextField.text isEqualToString:@"n"]) {
作为您的条件，因此如果整个myTextField.text等于""，则执行块。但是，如果您没有输入除"">以外的任何内容，则整个myTextField.text仅等于""。这就是为什么现在，这段代码只在"用户第一次按 Enter 时"工作;当你说"我什至不能退格键"时，问题实际上是项目符号点被重新添加到对textViewDidChange:的调用中，因为仍然满足相同的条件。
在这种情况下，我建议不要使用shouldChangeTextInRange: textViewDidChange:，这样您就可以知道替换文本是什么，无论它在UITextView文本字符串中的位置如何。通过使用此方法，即使在文本块中间输入换行符，您也可以自动插入项目符号点......例如，如果用户决定输入一堆信息，然后跳回几行以输入更多信息，然后尝试在两者之间按换行符，则以下内容应该仍然有效。以下是我的建议：
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text {
// If the replacement text is "n" and the
// text view is the one you want bullet points
// for
if ([text isEqualToString:@"n"]) {
// If the replacement text is being added to the end of the
// text view, i.e. the new index is the length of the old
// text view's text...
if (range.location == textView.text.length) {
// Simply add the newline and bullet point to the end
NSString *updatedText = [textView.text stringByAppendingString:@"nu2022 "];
[textView setText:updatedText];
}
// Else if the replacement text is being added in the middle of
// the text view's text...
else {
// Get the replacement range of the UITextView
UITextPosition *beginning = textView.beginningOfDocument;
UITextPosition *start = [textView positionFromPosition:beginning offset:range.location];
UITextPosition *end = [textView positionFromPosition:start offset:range.length];
UITextRange *textRange = [textView textRangeFromPosition:start toPosition:end];
// Insert that newline character *and* a bullet point
// at the point at which the user inputted just the
// newline character
[textView replaceRange:textRange withText:@"nu2022 "];
// Update the cursor position accordingly
NSRange cursor = NSMakeRange(range.location + @"nu2022 ".length, 0);
textView.selectedRange = cursor;
}
// Then return "NO, don't change the characters in range" since
// you've just done the work already
return NO;
}
// Else return yes
return YES;
}
以防万一，有人正在寻找解决同一问题的 Swift 2.x 解决方案，这里有一个解决方案：
func textView(textView: UITextView, shouldChangeTextInRange range: NSRange, replacementText text: String) -> Bool {
// If the replacement text is "n" and the
// text view is the one you want bullet points
// for
if (text == "n") {
// If the replacement text is being added to the end of the
// text view, i.e. the new index is the length of the old
// text view's text...
if range.location == textView.text.characters.count {
// Simply add the newline and bullet point to the end
var updatedText: String = textView.text!.stringByAppendingString("n u{2022} ")
textView.text = updatedText
}
else {
// Get the replacement range of the UITextView
var beginning: UITextPosition = textView.beginningOfDocument
var start: UITextPosition = textView.positionFromPosition(beginning, offset: range.location)!
var end: UITextPosition = textView.positionFromPosition(start, offset: range.length)!
var textRange: UITextRange = textView.textRangeFromPosition(start, toPosition: end)!
// Insert that newline character *and* a bullet point
// at the point at which the user inputted just the
// newline character
textView.replaceRange(textRange, withText: "n u{2022} ")
// Update the cursor position accordingly
var cursor: NSRange = NSMakeRange(range.location + "n u{2022} ".length, 0)
textView.selectedRange = cursor
}
return false
}
// Else return yes
return true
}
斯威夫特 5.x 版本。
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
//
// If the replacement text is "n" and the
// text view is the one you want bullet points
// for
if (text == "n") {
// If the replacement text is being added to the end of the
// text view, i.e. the new index is the length of the old
// text view's text...
if range.location == textView.text.count {
// Simply add the newline and bullet point to the end
let updatedText: String = textView.text! + "n u{2022} "
textView.text = updatedText
}
else {
// Get the replacement range of the UITextView
let beginning: UITextPosition = textView.beginningOfDocument
let start: UITextPosition = textView.position(from: beginning, offset: range.location)!
let end: UITextPosition = textView.position(from: start, offset: range.length)!
let textRange: UITextRange = textView.textRange(from: start, to: end)!
// Insert that newline character *and* a bullet point
// at the point at which the user inputted just the
// newline character
textView.replace(textRange, withText: "n u{2022} ")
// Update the cursor position accordingly
let cursor: NSRange = NSMakeRange(range.location + "n u{2022} ".count, 0)
textView.selectedRange = cursor
}
return false
}
// Else return yes
return true
}