[英]Replace UITextViews text with attributed string
我有一个UITextView
,当用户在其中输入文本时,我想即时格式化文本。 像语法高亮这样的东西......
为此,我想使用UITextView
...
一切正常,但有一个问题:我从文本视图中获取文本并从中创建一个NSAttributedString
。 我对此属性字符串进行了一些编辑,并将其重新设置为textView.attributedText
。
每次用户键入时都会发生这种情况。 所以我必须在编辑到attributedText
selectedTextRange
之前记住selectedTextRange
并在之后将其设置回来,以便用户可以继续在他之前输入的地方输入。 唯一的问题是,一旦文本足够长需要滚动,如果我输入缓慢, UITextView
现在将开始滚动到顶部。
下面是一些示例代码:
- (void)formatTextInTextView:(UITextView *)textView
{
NSRange selectedRange = textView.selectedRange;
NSString *text = textView.text;
// This will give me an attributedString with the base text-style
NSMutableAttributedString *attributedString = [self attributedStringFromString:text];
NSError *error = nil;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"#(\\w+)" options:0 error:&error];
NSArray *matches = [regex matchesInString:text
options:0
range:NSMakeRange(0, text.length)];
for (NSTextCheckingResult *match in matches)
{
NSRange matchRange = [match rangeAtIndex:0];
[attributedString addAttribute:NSForegroundColorAttributeName
value:[UIColor redColor]
range:matchRange];
}
textView.attributedText = attributedString;
textView.selectedRange = selectedRange;
}
有没有不直接使用 CoreText 的解决方案? 我喜欢UITextView
的选择文本等功能....
我不确定这是正确的解决方案,但它有效。
只需在格式化文本之前禁用滚动并在格式化后启用它
- (void)formatTextInTextView:(UITextView *)textView
{
textView.scrollEnabled = NO;
NSRange selectedRange = textView.selectedRange;
NSString *text = textView.text;
// This will give me an attributedString with the base text-style
NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:text];
NSError *error = nil;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"#(\\w+)" options:0 error:&error];
NSArray *matches = [regex matchesInString:text
options:0
range:NSMakeRange(0, text.length)];
for (NSTextCheckingResult *match in matches)
{
NSRange matchRange = [match rangeAtIndex:0];
[attributedString addAttribute:NSForegroundColorAttributeName
value:[UIColor redColor]
range:matchRange];
}
textView.attributedText = attributedString;
textView.selectedRange = selectedRange;
textView.scrollEnabled = YES;
}
我自己使用了 Sergeys 的答案并将其移植到 Swift 2:
func formatTextInTextView(textView: UITextView) {
textView.scrollEnabled = false
let selectedRange = textView.selectedRange
let text = textView.text
// This will give me an attributedString with the base text-style
let attributedString = NSMutableAttributedString(string: text)
let regex = try? NSRegularExpression(pattern: "#(\\w+)", options: [])
let matches = regex!.matchesInString(text, options: [], range: NSMakeRange(0, text.characters.count))
for match in matches {
let matchRange = match.rangeAtIndex(0)
attributedString.addAttribute(NSForegroundColorAttributeName, value: UIColor.redColor(), range: matchRange)
}
textView.attributedText = attributedString
textView.selectedRange = selectedRange
textView.scrollEnabled = true
}
在 Swift 4 中:
func createAttributedText() {
let stringText = "Test String"
let stringCount = stringText.count
let string: NSMutableAttributedString = NSMutableAttributedString(string: stringText)
string.addAttribute(NSForegroundColorAttributeName, value: UIColor.red, range: NSMakeRange(0, stringCount))
self.textView.attributedText = string
}
斯威夫特 2.0:
let myDisplayTxt:String = "Test String"
let string: NSMutableAttributedString = NSMutableAttributedString(string: self.myDisplayTxt)
string.addAttribute(NSForegroundColorAttributeName, value: UIColor.redColor(), range: NSMakeRange(0, 5))
string.addAttribute(String(kCTForegroundColorAttributeName), value: UIColor.redColor().CGColor as AnyObject, range: NSMakeRange(0, 5))
self.sampleTextView.attributedText = string
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