如何检测UITextView中下划线的敲击？

Question

I have a UITextView with certain words being replaced out by underscores to give it a fill in the blanks effect. I am having difficulties detecting taps on these 'blanks'. What I have tried so far is to get the range of the word that was tapped on using rangeEnclosingPosition with Granularity set to Word but it looks like it does not recognise taps on special characters. Now, I am looking to give my 'underscore' strings custom attributes so I can then check to see if the word that was tapped on had any custom attributes set. Any ideas would be really helpful please.

Answer 1

您可以尝试使用UITextViewDelegate方法-textViewDidChangeSelection ，当插入符在文本视图中的位置发生更改时得到通知，如果插入符当前位置的下一个字符是您的特殊字符，请在此处进行逻辑处理。

Answer 2

Here is how I did it -

Add custom attributes to the special characters in your text. In my case, I knew the special characters would be all underscores or that was only what I was looking for. So I added a custom attribute in the following manner -

NSAttributedString* attributedString = [[NSAttributedString alloc] initWithString:underscoreString attributes:@{ @"yourCustomAttribute" : @"value", NSFontAttributeName : [ UIFont boldSystemFontOfSize:22.0] }];

To look for taps on the special character, add a UITapGestureRecognizer in the following manner -

UITapGestureRecognizer *textViewTapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tappedTextView:)];
textViewTapRecognizer.delegate = self;
[self.textView addGestureRecognizer:textViewTapRecognizer];

and define its selector in the following manner -

-(void) tappedTextView:(UITapGestureRecognizer *)recognizer
{
UITextView *textView = (UITextView *)recognizer.view;

// Location of the tap in text-container coordinates

NSLayoutManager *layoutManager = textView.layoutManager;
CGPoint location = [recognizer locationInView:textView];
location.x -= textView.textContainerInset.left;
location.y -= textView.textContainerInset.top;

// Find the character that's been tapped on

NSUInteger characterIndex;
characterIndex = [layoutManager characterIndexForPoint:location
                                       inTextContainer:textView.textContainer
              fractionOfDistanceBetweenInsertionPoints:NULL];
NSString *value;
if (characterIndex < textView.textStorage.length) {
    NSRange range;
    value = [[textView.attributedText attribute:@"yourCustomAttribute" atIndex:characterIndex effectiveRange:&range] intValue];
    NSLog(@"%@, %lu, %lu", value, (unsigned long)range.location, (unsigned long)range.length);
}
}

If you get a value, your special character was tapped. There could be better ways of doing this but this worked for me for now.