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使用CoreText和Touchs创建可单击的操作

core-text ipad objective-c iphone

9

jer · 技术社区 · 15 年前

UIWebView 只是为了得到可点击的链接。一旦用户点击该链接(而不是整个表视图单元格),我想启动一个委托方法,然后用它来呈现一个模式视图,其中包含指向该url的web视图。

我将路径和字符串本身保存为视图的实例变量,绘图代码在 -drawRect:

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [touches anyObject];
    CGPoint point = [touch locationInView:self];
    CGContextRef context = UIGraphicsGetCurrentContext();

    NSLog(@"attribString = %@", self.attribString);
    CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)self.attribString);
    CTFrameRef ctframe = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, self.attribString.length), attribPath, NULL);

    CFArrayRef lines = CTFrameGetLines(ctframe);
    for(CFIndex i = 0; i < CFArrayGetCount(lines); i++)
    {
        CTLineRef line = CFArrayGetValueAtIndex(lines, i);
        CGRect lineBounds = CTLineGetImageBounds(line, context);

        // Check if tap was on our line
        if(CGRectContainsPoint(lineBounds, point))
        {
            NSLog(@"Tapped line");
            CFArrayRef runs = CTLineGetGlyphRuns(line);
            for(CFIndex j = 0; j < CFArrayGetCount(runs); j++)
            {
                CTRunRef run = CFArrayGetValueAtIndex(runs, j);
                CFRange urlStringRange = CTRunGetStringRange(run); 
                CGRect runBounds = CTRunGetImageBounds(run, context, urlStringRange);

                if(CGRectContainsPoint(runBounds, point))
                {
                    NSLog(@"Tapped run");
                    CFIndex* buffer = malloc(sizeof(CFIndex) * urlStringRange.length);
                    CTRunGetStringIndices(run, urlStringRange, buffer);
                    // TODO: Map the glyph indices to indexes in the string & Fire the delegate
                }
            }
        }
    }
}

这不是目前最漂亮的代码,我仍在努力让它工作,所以请原谅代码质量。

"Tapped line" 如果我点击同一行,链接就会被打印出来,这是不会发生的,我希望两者都是 “抽头线” 和 "Tapped run" 如果我点击网址就会被打印出来。

更新 :我已将问题缩小为协调问题。我已经翻转了坐标(并没有如上所示),我得到的问题是,我接触寄存器,因为我期望,但坐标空间是翻转,我似乎不能翻转回来。

3 回复 | 直到 15 年前

1

9

Nick Hingston 13 年前

我刚刚这样做是为了从touch位置获取字符串索引。在这种情况下,行号为i:

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    NSLog(@"touch ended");

    UITouch* touch = [touches anyObject];

    CGPoint pnt = [touch locationInView:self];

    CGPoint reversePoint = CGPointMake(pnt.x, self.frame.size.height-pnt.y);

    CFArrayRef lines = CTFrameGetLines(ctFrame);

    CGPoint* lineOrigins = malloc(sizeof(CGPoint)*CFArrayGetCount(lines));

    CTFrameGetLineOrigins(ctFrame, CFRangeMake(0,0), lineOrigins);

    for(CFIndex i = 0; i < CFArrayGetCount(lines); i++)
    {
        CTLineRef line = CFArrayGetValueAtIndex(lines, i);

        CGPoint origin = lineOrigins[i];
        if (reversePoint.y > origin.y) {
            NSInteger index = CTLineGetStringIndexForPosition(line, reversePoint);
            NSLog(@"index %d", index);
            break;
        }
    }
    free(lineOrigins);
}

2

0

msg 15 年前

你可以试着把你的文本图形添加到一个CALayer中,把这个新图层作为你的视图图层的子图层,然后在你的touchesend中对它进行hittest?如果您这样做,您应该能够创建一个更大的可触摸区域,使层大于绘制的文本。

// hittesting 
UITouch *touch = [[event allTouches] anyObject];
touchedLayer = (CALayer *)[self.layer hitTest:[touch locationInView:self]];

3

0

KristopherGBaker 8 年前

尼克H247答案的Swift 3版本:

var ctFrame: CTFrame?

override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    guard let touch = touches.first, let ctFrame = self.ctFrame else { return }

    let pnt = touch.location(in: self.view)
    let reversePoint = CGPoint(x: pnt.x, y: self.frame.height - pnt.y)
    let lines = CTFrameGetLines(ctFrame) as [AnyObject] as! [CTLine]

    var lineOrigins = [CGPoint](repeating: .zero, count: lines.count)
    CTFrameGetLineOrigins(ctFrame, CFRange(location: 0, length: 0), &lineOrigins)

    for (i, line) in lines.enumerated() {
        let origin = lineOrigins[i]

        if reversePoint.y > origin.y {
            let index = CTLineGetStringIndexForPosition(line, reversePoint)
            print("index \(index)")
            break
        }
    }
}