iOS7 - 调整多行标签的字体大小以适合其框架

Posted 2023-03-06

【中文标题】iOS7 - 调整多行标签的字体大小以适合其框架

【英文标题】：iOS7 - Adjusting font size of multiline label to fit its frame

【发布时间】：2015-05-07 19:52:57

【问题描述】：

我需要在 UILabel 的框架中添加多行属性文本。 阅读此线程 How to adjust font size of label to fit the rectangle? 我从 Niels 的解决方案开始，以便使用属性文本。

代码如下：'prospect' 的 't' 换行，而我需要不要截断单词；在此示例中，我希望将字体大小再减小一点，以便将 'prospect 放在一行中。

UILabel *myLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 180, 180)];
myLabel.font = [UIFont fontWithName:@"Arial" size:5];
myLabel.adjustsFontSizeToFitWidth = YES;
myLabel.backgroundColor = [UIColor orangeColor];
myLabel.numberOfLines = -1;
myLabel.lineBreakMode = NSLineBreakByWordWrapping;

NSMutableParagraphStyle *paragraphStyle = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
[paragraphStyle setLineSpacing:8];
[paragraphStyle setAlignment:NSTextAlignmentLeft];
NSDictionary *attributes = @ NSFontAttributeName:myLabel.font, NSParagraphStyleAttributeName: paragraphStyle ;

NSAttributedString *attributedString = [[NSAttributedString alloc] initWithString:@"New Prospect" attributes:attributes];
myLabel.attributedText = attributedString;
myLabel.font = [UIFont fontWithName:@"Arial" size:160];
[self sizeLabel:myLabel toRect:myLabel.frame];

[self.view addSubview:myLabel];

sizeLabel方法实现如下：

- (void) sizeLabel 
    int fontSize = self.font.pointSize;
    int minFontSize = 5;

    // Fit label width wize
    CGSize constraintSize = CGSizeMake(self.frame.size.width, MAXFLOAT);

    do 
        // Set current font size
        self.font = [UIFont fontWithName:self.font.fontName size:fontSize];

        // Find label size for current font size
        CGRect textRect = [[self attributedText] boundingRectWithSize:constraintSize
                                                     options:NSStringDrawingUsesLineFragmentOrigin
                                                     context:nil];

        CGSize labelSize = textRect.size;

        // Done, if created label is within target size
        if( labelSize.height <= self.frame.size.height )
            break;

        // Decrease the font size and try again
        fontSize -= 2;

     while (fontSize > minFontSize);

有什么想法吗？ 谢谢， 丹

【问题讨论】：

您找到解决方案了吗？我有同样的问题:(

【参考方案1】：

您还需要检查每个单词以确保它们没有被截断，因为boundingRectWithSize: 永远不会返回比您提供的宽度更宽的 CGRect（即使单个单词不适合宽度）。这是一个类似的循环，其中包含该机制：

- (void)setButtonTitle:(NSString *)title

    CGFloat fontSize = 20; // The max font size you want to use
    CGFloat minimumFontSize = 5; // The min font size you want to use
    CGFloat labelHeightWithFont = 0;
    CGFloat longestWordWidth = 0;
    UIFont *labelFont = nil;

    CGFloat buttonLabelMaxWidth = self.size.width;

    do 

        if (fontSize < minimumFontSize) 
            // Handle exception where the title just won't fit
            break;
        

        // Trying the current font size if it fits
        labelFont = [UIFont systemFontOfSize:fontSize--];
        CGSize boundingSize = [self boundingSizeForString:title font:labelFont];
        labelHeightWithFont = boundingSize.height;

        // Be sure that words are not truncated (that they fits in the maximum width)
        longestWordWidth = 0;
        for (NSString *word in [title componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]) 
            CGSize wordSize = [word sizeWithAttributes:@NSFontAttributeName: labelFont];
            longestWordWidth = MAX(longestWordWidth, wordSize.width);
        

        // Loop until the text at the current size fits the maximum width/height.
     while (labelHeightWithFont > buttonLabelMaxWidth || longestWordWidth > buttonLabelMaxWidth);

    self.buttonLabel.text = title;
    self.buttonLabel.font = labelFont;


- (CGSize)boundingSizeForString:(NSString *)string font:(UIFont *)font


    CGRect boundingRect = [string boundingRectWithSize:CGSizeMake([self buttonLabelMaxWidth], MAXFLOAT)
                                options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading
                             attributes:@NSFontAttributeName: font
                                context:nil];
    return CGSizeMake(ceilf(boundingRect.size.width), ceilf(boundingRect.size.height));