ios 将背景图像添加到 UILabel
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Adding Background image to UILabel
提问by Joy
How can I add a background image to a UILabel in an iPhone Application. I've tried to do it through IB but with no result.
如何将背景图像添加到 iPhone 应用程序中的 UILabel。我试图通过 IB 来做到这一点，但没有结果。
回答by Evadne Wu
Try doing it with code:
尝试用代码来做：
Objective-C:
目标-C：
theLabel.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"blah"]];
Swift:
迅速：
theLabel.backgroundColor = UIColor(patternImage: UIImage(named: "blah")!)
Or place an UIImageViewbehind the label (not recommended).
或者UIImageView在标签后面放置一个（不推荐）。
Update: placing an UIImageView behind a label was not recommended because then you would have to manage two views. But if you must do something that only an UIImageView can do this is still a good approach. I suspect that your app will actually run better this way.
更新：不建议将 UIImageView 放在标签后面，因为这样您就必须管理两个视图。但是如果你必须做一些只有 UIImageView 可以做的事情，这仍然是一个很好的方法。我怀疑您的应用程序实际上会以这种方式运行得更好。
回答by Lê Trinh
if you want that image should be stretched to fill the Label width. try this code.
如果您希望该图像应该被拉伸以填充标签宽度。试试这个代码。
UILabel *myLabel=[[UILabel alloc] initWithFrame:CGRectMake(0, 0, 320, 20)];
UIImage *img = [UIImage imageNamed:@"a.png"];
CGSize imgSize = myLabel.frame.size;
UIGraphicsBeginImageContext( imgSize );
[img drawInRect:CGRectMake(0,0,imgSize.width,imgSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
myLabel.backgroundColor = [UIColor colorWithPatternImage:newImage];
回答by Bill Chan
Swift 2.2: set the Background image with background color
Swift 2.2：使用背景颜色设置背景图像
UIGraphicsBeginImageContextWithOptions(stationNameLabel.frame.size, false, 0.0)
let context = UIGraphicsGetCurrentContext();
let components = CGColorGetComponents(color.CGColor)
CGContextSetRGBFillColor(context, components[0], components[1], components[2], 0.4);
CGContextFillRect(context, CGRectMake(0.0, 0.0, stationNameLabel.frame.size.width, stationNameLabel.frame.size.height));
targetImage.drawInRect(CGRectMake(0.0, 0.0, stationNameLabel.frame.size.width, stationNameLabel.frame.size.height))
let resultImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
label.backgroundColor = UIColor(patternImage: resultImage)
回答by Davender Verma
let messageBackgroundView = UIImageView()
messageBackgroundView.image = UIImage(named: "chat-background")
if messageBackgroundView.superview != lblChatdata.superview {
lblChatdata.superview!.insertSubview(messageBackgroundView, belowSubview: lblChatdata)
messageBackgroundView.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
messageBackgroundView.leadingAnchor.constraint(equalTo: lblChatdata.leadingAnchor),
messageBackgroundView.trailingAnchor.constraint(equalTo: lblChatdata.trailingAnchor),
messageBackgroundView.topAnchor.constraint(equalTo: lblChatdata.topAnchor),
messageBackgroundView.bottomAnchor.constraint(equalTo: lblChatdata.bottomAnchor),
])
messageBackgroundView.contentMode = .scaleAspectFill
}
回答by Ikechukwu Henry Odoh
@pixelfreak, your right. UIColor instance with color image pattern has serious performance issues when assigning it to backroundcolor
@pixelfreak，你的权利。具有彩色图像图案的 UIColor 实例在将其分配给背景色时存在严重的性能问题
cell.cellLabel.backgroundColor = UIColor(patternImage: UIImage(named: "background")!)
