Swift - 角半径和投影的问题

问题描述

我正在尝试创建一个带有圆角和投影的按钮。无论我如何切换，按钮都无法正确显示。我已经尝试过 masksToBounds = false 和 masksToBounds = true ，但角半径是否有效且阴影没有或是阴影工作，角半径不会剪切按钮的角落。

I'm trying to create a button with rounded corners and a drop shadow. No matter how I switch up, the button will not display correctly. I've tried masksToBounds = false and masksToBounds = true, but either the corner radius works and the shadow does not or the shadow works and the corner radius doesn't clip the corners of the button.

import UIKit
import QuartzCore

@IBDesignable
class Button : UIButton
{
    @IBInspectable var masksToBounds: Bool    = false                {didSet{updateLayerProperties()}}
    @IBInspectable var cornerRadius : CGFloat = 0                    {didSet{updateLayerProperties()}}
    @IBInspectable var borderWidth  : CGFloat = 0                    {didSet{updateLayerProperties()}}
    @IBInspectable var borderColor  : UIColor = UIColor.clearColor() {didSet{updateLayerProperties()}}
    @IBInspectable var shadowColor  : UIColor = UIColor.clearColor() {didSet{updateLayerProperties()}}
    @IBInspectable var shadowOpacity: CGFloat = 0                    {didSet{updateLayerProperties()}}
    @IBInspectable var shadowRadius : CGFloat = 0                    {didSet{updateLayerProperties()}}
    @IBInspectable var shadowOffset : CGSize  = CGSizeMake(0, 0)     {didSet{updateLayerProperties()}}

    override func drawRect(rect: CGRect)
    {
        updateLayerProperties()
    }

    func updateLayerProperties()
    {
        self.layer.masksToBounds = masksToBounds
        self.layer.cornerRadius = cornerRadius
        self.layer.borderWidth = borderWidth
        self.layer.borderColor = borderColor.CGColor
        self.layer.shadowColor = shadowColor.CGColor
        self.layer.shadowOpacity = CFloat(shadowOpacity)
        self.layer.shadowRadius = shadowRadius
        self.layer.shadowOffset = shadowOffset
    }
}

推荐答案

以下Swift 3代码显示了如何设置允许的 UIButton 的子类创建带圆角和阴影的实例：

The following Swift 3 code shows how to set a subclass of UIButton that allows to create instances with rounded corners and shadow around it:

import UIKit

class CustomButton: UIButton {

    var shadowLayer: CAShapeLayer!

    override func layoutSubviews() {
        super.layoutSubviews()

        if shadowLayer == nil {
            shadowLayer = CAShapeLayer()
            shadowLayer.path = UIBezierPath(roundedRect: bounds, cornerRadius: 12).cgPath
            shadowLayer.fillColor = UIColor.white.cgColor

            shadowLayer.shadowColor = UIColor.darkGray.cgColor
            shadowLayer.shadowPath = shadowLayer.path
            shadowLayer.shadowOffset = CGSize(width: 2.0, height: 2.0)
            shadowLayer.shadowOpacity = 0.8
            shadowLayer.shadowRadius = 2

            layer.insertSublayer(shadowLayer, at: 0)
            //layer.insertSublayer(shadowLayer, below: nil) // also works
        }
    }

}

---

根据您的需要，您可以添加 UIButton 并将其类设置为 CustomButton 或者您可以以编程方式创建 CustomButton 的实例。以下 UIViewController 实现显示了如何以编程方式创建和使用 CustomButton 实例：

---

According to your needs, you may add a UIButton in your Storyboard and set its class to CustomButton or you may create an instance of CustomButton programmatically. The following UIViewController implementation shows how to create and use a CustomButton instance programmatically:

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let button = CustomButton(type: .system)
        button.setTitle("Button", for: .normal)
        view.addSubview(button)

        // Auto layout code using anchors (iOS9+)
        // set witdh and height constraints if necessary
        button.translatesAutoresizingMaskIntoConstraints = false
        let horizontalConstraint = button.centerXAnchor.constraint(equalTo: view.centerXAnchor)
        let verticalConstraint = button.centerYAnchor.constraint(equalTo: view.centerYAnchor)
        let widthConstraint = button.widthAnchor.constraint(equalToConstant: 100)
        let heightConstraint = button.heightAnchor.constraint(equalToConstant: 100)
        NSLayoutConstraint.activate([horizontalConstraint, verticalConstraint, widthConstraint, heightConstraint])
    }

}

---

上一代码在iPhone模拟器中生成以下图片：

---

The previous code produces the image below in the iPhone simulator:

这篇关于Swift - 角半径和投影的问题的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！