计算 UILabel 文本大小

Question

我正在以编程方式绘制UILabels。他们从数据库中获取大小。所以我不能只使用sizeToFit。我已经实现了一个以通过率重绘UILabels 的函数。所以我只需要找到UILabel 中的文本，从我的角度来看，这需要最大比率来重绘UILabels。 所以最后我需要做这样的事情：

    double ratio = 1.00;
    for (UILabel* labels in sec.subviews) {

        float widthLabel = labels.frame.size.width;
        float heightLabel = labels.frame.size.height;
        float heightText = //get the text height here
        float widthText = //get the text width here
        if (widthLabel < widthText) {
            ratio = MAX(widthText/widthLabel,ratio);
        }
        if (heightLabel < heightText) {
            ratio = MAX(heightText/heightLabel, ratio);
        }
    }
    //redraw UILabels with the given ratio here

那么我怎样才能获得文本的高度和宽度大小，因为我的一些文本不适合标签我不能简单地使用标签边界？我正在使用 Xcode 5 和 iOS 7。

Answer 1

所有 [NSString sizeWithFont...] 方法在 iOS 7 中都已弃用。请改用它。

CGRect labelRect = [text
                    boundingRectWithSize:labelSize
                    options:NSStringDrawingUsesLineFragmentOrigin
                    attributes:@{
                     NSFontAttributeName : [UIFont systemFontOfSize:14]
                    }
                    context:nil];

另见https://developer.apple.com/documentation/foundation/nsstring/1619914-sizewithfont。

更新 - boundingRectWithSize 输出示例

根据您的评论，我做了一个简单的测试。代码和输出如下。

// code to generate a bounding rect for text at various font sizes
NSString *text = @"This is a long sentence. Wonder how much space is needed?";
for (NSNumber *n in @[@(12.0f), @(14.0f), @(18.0f)]) {
    CGFloat fontSize = [n floatValue];
    CGRect r = [text boundingRectWithSize:CGSizeMake(200, 0)
                                  options:NSStringDrawingUsesLineFragmentOrigin
                               attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:fontSize]}
                                  context:nil];
    NSLog(@"fontSize = %f\tbounds = (%f x %f)",
          fontSize,
          r.size.width,
          r.size.height);
}

这会产生以下输出（请注意，随着字体大小变大，边界会按预期变化）：

fontSize = 12.000000    bounds = (181.152008 x 28.632000)
fontSize = 14.000000    bounds = (182.251999 x 50.105999)
fontSize = 18.000000    bounds = (194.039993 x 64.421997)

Answer 2

Length 获取字符数。如果要获取文字的宽度：

Objective-C

CGSize textSize = [label.text sizeWithAttributes:@{NSFontAttributeName:[label font]}];

斯威夫特 4

let size = label.text?.size(withAttributes: [.font: label.font]) ?? .zero

这会让你得到大小。并且可以比较每个标签的textSize.width。

Answer 3

另一种我还没有提到的简单方法：

CGSize textSize = [label intrinsicContentSize];

（当然，这只有在您设置了标签的文本和字体后才能正常工作。）

Answer 4

这是一个 swift 变体。

let font = UIFont(name: "HelveticaNeue", size: 25)!
let text = "This is some really long text just to test how it works for calculating heights in swift of string sizes. What if I add a couple lines of text?"

let textString = text as NSString

let textAttributes = [NSFontAttributeName: font]

textString.boundingRectWithSize(CGSizeMake(320, 2000), options: .UsesLineFragmentOrigin, attributes: textAttributes, context: nil)

Answer 5

小伙子们，如果你像我一样使用，boundingRectWithSize 和 [UIFont systemFontOFSize:14]

如果您的字符串是两行长，则返回的矩形高度大约是 33,4 点。

不要像我一样犯错误，将其转换为int，因为 33,4 变成 33，33 点高度标签从两到一行传递！

Answer 6

问题

CGRect r = [text boundingRectWithSize:CGSizeMake(200, 0)
                              options:NSStringDrawingUsesLineFragmentOrigin
                           attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:fontSize]}
                              context:nil];

是boundingRectWithSize，它决定了CGRect可以有的最大值。

我对这个问题的解决方案是检查它是否超过，如果没有，那么文本可以适合标签。我通过使用循环来做到这一点。

NSString *text = @"This is a long sentence. Wonder how much space is needed?";
CGFloat width = 100;
CGFloat height = 100;
bool sizeFound = false;
while (!sizeFound) {
    NSLog(@"Begin loop");
    CGFloat fontSize = 14;
    CGFloat previousSize = 0.0;
    CGFloat currSize = 0.0;
    for (float fSize = fontSize; fSize < fontSize+6; fSize++) {
        CGRect r = [text boundingRectWithSize:CGSizeMake(width, height)
                                      options:NSStringDrawingUsesLineFragmentOrigin
                                   attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:fSize]}
                                      context:nil];
        currSize =r.size.width*r.size.height;
        if (previousSize >= currSize) {
            width = width*11/10;
            height = height*11/10;
            fSize = fontSize+10;
        }
        else {
            previousSize = currSize;
        }
        NSLog(@"fontSize = %f\tbounds = (%f x %f) = %f",
              fSize,
              r.size.width,
              r.size.height,r.size.width*r.size.height);
    }
    if (previousSize == currSize) {
        sizeFound = true;
    }

}
NSLog(@"Size found with width %f and height %f", width, height);

每次迭代后，高度和宽度的大小都会增加其值的 10%。

之所以选择 6，是因为我不想标签太糊。

对于不使用循环的解决方案：

NSString *text = @"This is a long sentence. Wonder how much space is needed?";
CGFloat width = 100;
CGFloat height = 100;

CGFloat currentFontSize = 12;
CGRect r1 = [text boundingRectWithSize:CGSizeMake(width, height)
                              options:NSStringDrawingUsesLineFragmentOrigin
                           attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:currentFontSize+6]}
                              context:nil];

CGRect r2 = [text boundingRectWithSize:CGSizeMake(width, height)
                               options:NSStringDrawingUsesFontLeading
                            attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:currentFontSize+6]}
                               context:nil];

CGFloat firstVal =r1.size.width*r1.size.height;
CGFloat secondVal =r2.size.width*r2.size.height;

NSLog(@"First val %f and second val is %f", firstVal, secondVal);

if (secondVal > firstVal) {
    float initRat = secondVal/firstVal;

    float ratioToBeMult = sqrtf(initRat);

    width *= ratioToBeMult;
    height *= ratioToBeMult;
}

NSLog(@"Final width %f and height %f", width, height);

//for verifying
for (NSNumber *n in @[@(12.0f), @(14.0f), @(17.0f)]) {
    CGFloat fontSize = [n floatValue];
    CGRect r = [text boundingRectWithSize:CGSizeMake(width, height)
                                  options:NSStringDrawingUsesLineFragmentOrigin
                               attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:fontSize]}
                                  context:nil];
    NSLog(@"fontSize = %f\tbounds = (%f x %f) = %f",
          fontSize,
          r.size.width,
          r.size.height,r.size.width*r.size.height);
    firstVal =r.size.width*r.size.height;
}

最后一个循环证明更大的字体可以产生更大的结果。

Answer 7

使用多行标签 (Swift 4) 的解决方案，从固定宽度计算高度：

let label = UILabel(frame: .zero)
label.numberOfLines = 0 // multiline
label.font = UIFont.systemFont(ofSize: UIFont.labelFontSize) // your font
label.preferredMaxLayoutWidth = width // max width
label.text = "This is a sample text.\nWith a second line!" // the text to display in the label

let height = label.intrinsicContentSize.height

Answer 8

通过这行代码我们可以得到标签上文字的大小。

let str = "Sample text"
let size = str.sizeWithAttributes([NSFontAttributeName:UIFont.systemFontOfSize(17.0)])

所以，我们可以同时使用宽度和高度。

Answer 9

msgStr 字符串获取大小：

let msgStr:NSString = Data["msg"]! as NSString
let messageSize = msgStr.boundingRect(with: CGSize(width: ChatTable.frame.width-116, height: CGFloat.infinity), options: .usesLineFragmentOrigin, attributes: [NSFontAttributeName:UIFont(name: "Montserrat-Light", size: 14)!], context: nil).size

Answer 10

Swift 3.0

func getLabelHeight() -> CGFloat {
    let font = UIFont(name: "OpenSans", size: 15)!
    let textString = "Lorem ipsum dolor sit er elit lamet, consectetaur cillium adipisicing pecu, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua." as NSString

    let textAttributes = [NSFontAttributeName: font]

    let rect = textString.boundingRect(with: CGSize(width: 320, height: 2000), options: .usesLineFragmentOrigin, attributes: textAttributes, context: nil)
    return rect.size.height
}

Answer 11

这是一个非常丑陋的混乱，因为如果你在设置 UILabel 字体之后使用属性字符串设置它，它会破坏属性文本中的字体信息，你必须根据文本+字体属性进行计算

有什么好调的

    CGFloat promptLabelMaxWidth = self.promptLabel.frame.size.width;
    NSAttributedString *attributedText = self.promptLabel.attributedText;
    assert(attributedText);
    CGRect rect = [attributedText boundingRectWithSize:(CGSize){promptLabelMaxWidth, CGFLOAT_MAX} options: NSStringDrawingUsesLineFragmentOrigin context:nil];
    NSString *text = self.promptLabel.text;
    UIFont *font = self.promptLabel.font;
    if (font) {
        CGRect r = [text boundingRectWithSize: CGSizeMake(promptLabelMaxWidth, CGFLOAT_MAX)
                                          options:NSStringDrawingUsesLineFragmentOrigin
                                       attributes:@{NSFontAttributeName: font}
                                          context:nil];
        if (r.size.height > rect.size.height) {
            rect = r;
        }
    }