用于设置按钮高度的 UIButton 子类 Xcode/Swift

Question

I have created a UIButton subclass to add a gradient layer to a batch of buttons and am wondering if there is a way to set the height of the buttons there as well because they'll all be the same height. This is my code for the gradient layer so I'm wondering if it's possible and where in the code I need to put it:

public class GradientButton: UIButton {

override public func layoutSubviews() {
    super.layoutSubviews()
    createGradientBackground()

}  
 func createGradientBackground() {

    let gradientLayer = CAGradientLayer()
    gradientLayer.frame = self.layer.bounds

    let color1 = UIColor(red:0.05, green:0.29, blue:0.49, alpha:1.0).CGColor as CGColorRef
    let color2 = UIColor(red:0.08, green:0.23, blue:0.39, alpha:1.0).CGColor as CGColorRef

    gradientLayer.colors = [color1, color2]

    gradientLayer.locations = [0.0, 1.0]

    self.layer.insertSublayer(gradientLayer, atIndex: 0)
    }
}

Answer 1

Sure, just add:

init() {
    self.frame.size.height = 50.0
    //Do other stuff you may want
}

OR:

func createGradientBackground() {

    let gradientLayer = CAGradientLayer()
    gradientLayer.frame = self.layer.bounds

    let color1 = UIColor(red:0.05, green:0.29, blue:0.49, alpha:1.0).CGColor as CGColorRef
    let color2 = UIColor(red:0.08, green:0.23, blue:0.39, alpha:1.0).CGColor as CGColorRef

    gradientLayer.colors = [color1, color2]

    gradientLayer.locations = [0.0, 1.0]

    self.layer.insertSublayer(gradientLayer, atIndex: 0)

    //set custom height wanted 
    self.frame.size.height = 50.0
}

You can do this in an custom init(), or inside of your createGradientBackground(). You do have to keep in mind of what constraints you are setting on your buttons in your storyboard however.

Answer 2

If your button has auto layout then you can update constraints runtime as follows:

import UIKit

class CustomButton: UIButton {

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setupConstraints()
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        setupConstraints()
    }

    func setupConstraints() {
        NSLayoutConstraint.activate([
            self.heightAnchor.constraint(equalToConstant: 50)
        ])
    }

    override class var requiresConstraintBasedLayout: Bool {
        return true
    }
}

Here you have to set requiresConstraintBasedLayout .

Custom views should override this to return true if they cannot layout correctly using autoresizing.

From Apple Documentation

Hope it helps you.

Answer 3

The simplest way to do it, is to override var intrinsicContentSize: CGSize .

Example:

open class AMPrimaryButton: UIButton {
    
    open override var intrinsicContentSize: CGSize {
        var size = super.intrinsicContentSize
        size.height = 50
        return size
    }
}