Swift UIButton子类并根据变量更改颜色

Question

I'm using a subclass for my UIButton and it has a variable called isActive. I need to change the button border color based on that variable. This variable will change programmatically. Please help me with this.

@IBDesignable
class buttonCTAOutlineDark: UIButton {

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

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

override func prepareForInterfaceBuilder() {
    commonInit()
}

@IBInspectable var isActive: Bool {
    get {
        return self.isActive
    }
    set (active) {
        if active {
            commonInit(isActive: active)
        }
    }
}

func commonInit(isActive: Bool = false) {
    self.backgroundColor = .clear
    self.layer.cornerRadius = 4
    self.layer.borderWidth = 1

    if (isActive) {
        self.tintColor = ACTIVE_COLOR
        self.layer.borderColor = ACTIVE_COLOR.cgColor
    } else {
        self.tintColor = nil
        self.layer.borderColor = UIColor(red:0.69, green:0.72, blue:0.77, alpha:1.0).cgColor
    }
}
}

Answer 1

You should be observing didSet to update the view . In Swift , type names should start with Uppercase eg ButtonCTAOutlineDark . Please see the fixed class,

@IBDesignable
class ButtonCTAOutlineDark: UIButton {

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

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

    @IBInspectable var isActive: Bool = false {
        didSet {
            self.commonInit(isActive: self.isActive)
        }
    }

    func commonInit(isActive: Bool = false) {
        self.backgroundColor = .clear
        self.layer.cornerRadius = 4
        self.layer.borderWidth = 1

        if (isActive) {
            self.tintColor = ACTIVE_COLOR
            self.layer.borderColor = ACTIVE_COLOR.cgColor
        } else {
            self.tintColor = nil
            self.layer.borderColor = UIColor(red:0.69, green:0.72, blue:0.77, alpha:1.0).cgColor
        }
    }
}

Answer 2

Your isActive property is written incorrectly. It should not be a computed property in the first place. Currently, the getter will just cause infinite recursion and the setter doesn't actually set anything.

The isActive property should be a stored property with a didSet property observer:

@IBInspectable
var isActive: Bool {
    didSet {

    }
}

Inside didSet , you can just put the last part of commonInit . The first part of commonInit doesn't need to be run every time isActive changes. I recommend you to extract that as a method called updateBorder :

func updateBorder(isActive: Bool) {

    if (isActive) {
        self.tintColor = ACTIVE_COLOR
        self.layer.borderColor = ACTIVE_COLOR.cgColor
    } else {
        self.tintColor = nil
        self.layer.borderColor = UIColor(red:0.69, green:0.72, blue:0.77, alpha:1.0).cgColor
    }

}

And then in didSet , you can just call that:

updateBorder(isActive: isActive)