如何在UILabel周围画边框？

Question

UILabel有没有办法在自己周围划出边界？这对我调试文本位置以及查看位置和标签实际大小非常有用.

Answer 1

您可以通过其基础CALayer属性设置标签的边框:

#import <QuartzCore/QuartzCore.h>

myLabel.layer.borderColor = [UIColor greenColor].CGColor;
myLabel.layer.borderWidth = 3.0;

Answer 2

以下是您可以做的一些事情UILabel及其边界.

以下是这些标签的代码:

import UIKit
class ViewController: UIViewController {

    @IBOutlet weak var label1: UILabel!
    @IBOutlet weak var label2: UILabel!
    @IBOutlet weak var label3: UILabel!
    @IBOutlet weak var label4: UILabel!
    @IBOutlet weak var label5: UILabel!
    @IBOutlet weak var label6: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()

        // label 1
        label1.layer.borderWidth = 1.0

        // label 2
        label2.layer.borderWidth = 5.0
        label2.layer.borderColor = UIColor.blue.cgColor

        // label 3
        label3.layer.borderWidth = 2.0
        label3.layer.cornerRadius = 8

        // label 4
        label4.backgroundColor = UIColor.cyan

        // label 5
        label5.backgroundColor = UIColor.red
        label5.layer.cornerRadius = 8
        label5.layer.masksToBounds = true

        // label 6
        label6.layer.borderWidth = 2.0
        label6.layer.cornerRadius = 8
        label6.backgroundColor = UIColor.yellow
        label6.layer.masksToBounds = true
    }
}

请注意,在Swift中无需导入QuartzCore.

也可以看看

• 边框,圆角和阴影 CALayer
• 解释 masksToBounds
• 使用带有Bezier路径的边框作为图层
• 如何进行变换 CALayer

Answer 3

Swift版本:

myLabel.layer.borderWidth = 0.5
myLabel.layer.borderColor = UIColor.greenColor().CGColor

对于Swift 3:

myLabel.layer.borderWidth = 0.5
myLabel.layer.borderColor = UIColor.green.cgColor

Answer 4

Swift 3/4 与 @IBDesignable

虽然几乎所有上述解决方案都可以正常工作，但我建议@IBDesignable为此使用自定义类。

@IBDesignable
class CustomLabel: UILabel {

    /*
    // Only override draw() if you perform custom drawing.
    // An empty implementation adversely affects performance during animation.
    override func draw(_ rect: CGRect) {
        // Drawing code
    }
    */

    @IBInspectable var borderColor: UIColor = UIColor.white {
        didSet {
            layer.borderColor = borderColor.cgColor
        }
    }

    @IBInspectable var borderWidth: CGFloat = 2.0 {
        didSet {
            layer.borderWidth = borderWidth
        }
    }

    @IBInspectable var cornerRadius: CGFloat = 0.0 {
        didSet {
            layer.cornerRadius = cornerRadius
        }
    }
}