我想检查我的 UILabel 是否被触摸。但我需要的不止这些。文字被触动了吗？现在，如果使用以下方法触摸了 UILabel 帧，我只会得到真/假:

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [[event allTouches] anyObject];
    if (CGRectContainsPoint([self.currentLetter frame], [touch locationInView:self.view]))
    {
        NSLog(@"HIT!");
    }
}

最佳答案

tl;博士:您可以点击测试文本的路径。 Gist is available here .

我会采用的方法是检查点击点是否在文本路径内。在详细介绍之前，让我为您概述一下这些步骤。

@interface TextHitTestingLabel (/*Private stuff*/)
@property (assign) CGPathRef textPath;
@end

- (void)setText:(NSString *)text {
    [super setText:text];

    [self textChanged];
}

- (void)setAttributedText:(NSAttributedString *)attributedText {
    [super setAttributedText:attributedText];

    [self textChanged];
}

- (void)awakeFromNib {
    [self textChanged];
}

#import <CoreText/CoreText.h>

// Get the text
NSAttributedString *attributedString = nil;
if ([self respondsToSelector:@selector(attributedText)]) { // Available in iOS 6
    attributedString = self.attributedText; 
}
if (!attributedString) { // Either earlier than iOS6 or the `text` property was set instead of `attributedText`
    attributedString = [[NSAttributedString alloc] initWithString:self.text
                                                       attributes:@{NSFontAttributeName: self.font}];
}

// Create a mutable path for the paths of all the letters.
CGMutablePathRef letters = CGPathCreateMutable();

// Create a line from the attributed string and get glyph runs from that line
CTLineRef line = CTLineCreateWithAttributedString((CFAttributedStringRef)attributedString);
CFArrayRef runArray = CTLineGetGlyphRuns(line);

// A line with more then one font, style, size etc will have multiple fonts.
// "Hello" formatted as " *Hel* lo " (spaces added for clarity) is two glyph
// runs: one italics and one regular. The first run contains 3 glyphs and the
// second run contains 2 glyphs.
// Note that " He *ll* o " is 3 runs even though "He" and "o" have the same font.
for (CFIndex runIndex = 0; runIndex < CFArrayGetCount(runArray); runIndex++)
{
    // Get the font for this glyph run.
    CTRunRef run = (CTRunRef)CFArrayGetValueAtIndex(runArray, runIndex);
    CTFontRef runFont = CFDictionaryGetValue(CTRunGetAttributes(run), kCTFontAttributeName);

    // This glyph run contains one or more glyphs (letters etc.)
    for (CFIndex runGlyphIndex = 0; runGlyphIndex < CTRunGetGlyphCount(run); runGlyphIndex++)
    {
        // Read the glyph itself and it position from the glyph run.
        CFRange glyphRange = CFRangeMake(runGlyphIndex, 1);
        CGGlyph glyph;
        CGPoint position;
        CTRunGetGlyphs(run, glyphRange, &glyph);
        CTRunGetPositions(run, glyphRange, &position);

        // Create a CGPath for the outline of the glyph
        CGPathRef letter = CTFontCreatePathForGlyph(runFont, glyph, NULL);
        // Translate it to its position.
        CGAffineTransform t = CGAffineTransformMakeTranslation(position.x, position.y);
        // Add the glyph to the 
        CGPathAddPath(letters, &t, letter);
        CGPathRelease(letter);
    }
}
CFRelease(line);

// Transform the path to not be upside down
CGAffineTransform t = CGAffineTransformMakeScale(1, -1); // flip 1
CGSize pathSize = CGPathGetBoundingBox(letters).size; 
t = CGAffineTransformTranslate(t, 0, -pathSize.height); // move down

// Create the final path by applying the transform
CGPathRef finalPath = CGPathCreateMutableCopyByTransformingPath(letters, &t);

// Clean up all the unused path
CGPathRelease(letters);

self.textPath = finalPath;

// Override -pointInside:withEvent to determine that ourselves.
- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event {
    // Check if the points is inside the text path.
    return CGPathContainsPoint(self.textPath, NULL, point, NO);
}

- (IBAction)labelWasTouched:(UITapGestureRecognizer *)sender {
    NSLog(@"LABEL!");
}

CGPathRef endPath = CGPathCreateMutableCopyByTransformingPath(letters, &t);

CGMutablePathRef finalPath = CGPathCreateMutableCopy(endPath);
CGPathRef strokedPath = CGPathCreateCopyByStrokingPath(endPath, NULL, 7, kCGLineCapRound, kCGLineJoinRound, 0);
CGPathAddPath(finalPath, NULL, strokedPath);

// Clean up all the unused paths
CGPathRelease(strokedPath);
CGPathRelease(letters);
CGPathRelease(endPath);

self.textPath = finalPath;

关于iphone - 如何检查 UILabel 文本是否被触摸？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/17259964/