ios - 在标签中的特定文本部分周围绘制边框

Question

我已附上标签的屏幕截图，应显示以下内容。时间戳文本附加有两幅图像和一个具有白色边框的文本。 我已经使用 NSTextAttachment 将图像附加到标签，然后我附加了必须在最后显示或在两个图像之间显示的文本，具体取决于条件。如果文本每次都在末尾出现，我可以通过再添加一个标签轻松实现这一点，但事实并非如此。我看到了很多为标签的完整文本创建边框的教程。有没有办法只为标签的特定部分创建边框标签文本。

Answer 1

你需要用你需要的文本制作一张图片，并作为 NSTextAttachment 附加到文本上，这里是它的实现

Objective-C 版本你可以这样制作你的PG图片

@implementation ImageHelper

+(UIImage*)imageForText:(NSString*)text{
        UILabel * lblBadge = [[UILabel alloc] initWithFrame:CGRectMake(0,0,16,16)];
        [lblBadge setTextAlignment:NSTextAlignmentCenter];
        [lblBadge setLineBreakMode:NSLineBreakByClipping];
        [lblBadge setTextColor:[UIColor darkGrayColor]];
        [lblBadge.layer setCornerRadius:2.0f];
        [lblBadge.layer setBorderWidth:1];
        [lblBadge setText:text];
        [lblBadge sizeToFit];
        [lblBadge setBounds:CGRectMake(0,0,lblBadge.bounds.size.width + 4,lblBadge.bounds.size.height)];

        UIGraphicsBeginImageContextWithOptions(lblBadge.bounds.size, NO, [UIScreen mainScreen].scale);
        [lblBadge.layer setAllowsEdgeAntialiasing:YES];
        [lblBadge.layer renderInContext:UIGraphicsGetCurrentContext()];
        UIImage * img = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        return img;
}

@end

使用示例

NSMutableAttributedString * normalNameString = [[NSMutableAttributedString alloc]initWithString:@"testing "];

NSTextAttachment * attachment = [[NSTextAttachment alloc] init];
attachment.image = [ImageHelper imageForText:@"PG-13"];
attachment.bounds = CGRectMake(0, -6, attachment.image.size.width, attachment.image.size.height);
[normalNameString appendAttributedString:[NSAttributedString attributedStringWithAttachment:attachment]];

self.lblText.attributedText = normalNameString;

Swift 版本

你可以这样制作你的PG图片

class imageHelper{
    static func pgImage(textValue:String) ->UIImage{
        let label = UILabel(frame: CGRect(x: 0, y: 0, width: 15, height: 16))
        label.lineBreakMode = .byClipping
        label.textAlignment = .center
        label.textColor = UIColor.darkGray
        label.layer.borderColor = UIColor.darkGray.cgColor
        label.layer.borderWidth = 1
        label.layer.cornerRadius = 2
        label.text = textValue
        label.sizeToFit()
        label.bounds = CGRect(x: 0, y: 0, width: label.bounds.size.width + 4, height: label.bounds.size.height)

        UIGraphicsBeginImageContextWithOptions(label.bounds.size, false, UIScreen.main.scale)
        label.layer.allowsEdgeAntialiasing = true
        label.layer.render(in: UIGraphicsGetCurrentContext()!)

        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image!
    }
}

使用示例

        let normalNameString = NSMutableAttributedString.init(string: "testing ")

        let attachment = NSTextAttachment()
        attachment.image = imageHelper.pgImage(textValue: "PG-13")
        attachment.bounds = CGRect(x: 0, y: -6, width: (attachment.image?.size.width)!, height: (attachment.image?.size.height)!)
        normalNameString.append(NSAttributedString(attachment: attachment))

        self.lblText.attributedText = normalNameString

结果