如何在 iOS 中增加 NSAttributedstring 的字体大小

Question

我正在尝试动态更改 NSAttributedString 的字体大小。问题是字符串包含不同的字体大小和属性。因此，当我更改字体大小时，所有内容大小都会更改为 tat 值。没有相应改变。 ... .

Answer 1

如果我对您的理解正确，这种方法应该对您有所帮助：您可以为您的 AttributedString 枚举所有 NSFontAttributeName 属性并将字体大小增加例如 1。这将为您提供以下结果：

如果这是你想要的，这里就是实现这个的代码

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.label = [[UILabel alloc] initWithFrame:CGRectMake(0., 0., 320., 320.)];
    self.label.textAlignment = NSTextAlignmentCenter;
    self.label.backgroundColor = [UIColor whiteColor];
    self.label.numberOfLines = 0.;
    NSString *text = @"Small medium large";
    NSMutableAttributedString *attributedText = [[NSMutableAttributedString alloc]     initWithString:text];
    [attributedText addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:10] range:NSMakeRange(0, 6)];
    [attributedText addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:15] range:NSMakeRange(6, 7)];
    [attributedText addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:25] range:NSMakeRange(13, 5)];
    self.label.attributedText = attributedText;
    [self.view addSubview:self.label];

    [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(bumpFontSize) userInfo:nil repeats:YES];
}

- (void)bumpFontSize
{
    NSMutableAttributedString *attributedText = [[NSMutableAttributedString alloc] initWithAttributedString:self.label.attributedText];
    [self.label.attributedText enumerateAttributesInRange:NSMakeRange(0., self.label.text.length) options:NSAttributedStringEnumerationReverse usingBlock:
     ^(NSDictionary *attributes, NSRange range, BOOL *stop)
    {
        NSMutableDictionary *mutableAttributes = [NSMutableDictionary dictionaryWithDictionary:attributes];
        UIFont *font = mutableAttributes[NSFontAttributeName];
        UIFontDescriptor *fontProperties = font.fontDescriptor;
        NSNumber *sizeNumber = fontProperties.fontAttributes[UIFontDescriptorSizeAttribute];
        [attributedText addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:    [sizeNumber floatValue] + 1.] range:range];
     }];
    self.label.attributedText = attributedText;
}