How can I Use Alpha Extension For All Object in swift? - ios

Question

I have below code for changing the value of object like text,image , ... with Effect. and it work:
UIView.animate(withDuration: 1.0, delay: 0.0, options: UIViewAnimationOptions.curveEaseOut, animations: {
self.lblCityTemp.alpha = 0.0
self.imgCityIcon.alpha = 0.0
}, completion: {
(finished: Bool) -> Void in
//Once the label is completely invisible, set the text and fade it back in
self.imgCityIcon.image = UIImage(named: icon)
self.lblCityTemp.text = "\(temp)°"
// Fade in
UIView.animate(withDuration: 1.0, delay: 0.0, options: UIViewAnimationOptions.curveEaseIn, animations: {
self.lblCityTemp.alpha = 1.0
self.imgCityIcon.alpha = 1.0
}, completion: nil)
})
Now I want make a extension of this code that I use for all my object that I write below code:
extension NSObject {
func Fade (alphaOUT: Double,alphaIN: Double, input: Any) {
UIView.animate(withDuration: 1.0, delay: 0.0, options: UIViewAnimationOptions.curveEaseOut, animations: {
self.alpha = CGFloat(alphaOUT)
}, completion: {
(finished: Bool) -> Void in
// Fade in
UIView.animate(withDuration: 1.0, delay: 0.0, options: UIViewAnimationOptions.curveEaseIn, animations: {
self.alpha = CGFloat(alphaIN)
}, completion: nil)
})
}
}
But I have error on self word and I do not know how can I set value for every object like label, imageView , ....
How can I do this?
Is the extension is best way or no?
If no, so what is the best way?

Answer 1

The whole idea should be take some UIView and animate it. Then you need extension of UIView since this class has properties that you need to.
extension UIView { ... }
Anyway, what now if you need to do something when animation ends? Then you'll need completion handler parameter for your method
func fade(..., completion: #escaping () -> Void = { }) {
... which will be called after the first animation ends.
Next suggestions:
You can say that alpha parameters should be of type CGFloat, then you don’t have to convert Double to CGFloat
Also, what is input? I think you won't need it with this solution
Method name should start with small capital letter and for naming parameters you should use camelCase
extension UIView {
func fade(alphaOut: CGFloat, alphaIn: CGFloat, completion: #escaping () -> Void = { }) {
UIView.animate(withDuration: 1, delay: 0, options: .curveEaseOut, animations: {
self.alpha = alphaOut
}, completion: { _ in
completion() // this is called when animation ends
UIView.animate(withDuration: 1, delay: 0, options: .curveEaseIn, animations: {
self.alpha = alphaIn
})
})
}
}
Then when you need to call it, change what you need after animation ends in completion closure
imgCityIcon.fade(alphaOut: ___, alphaIn: ___) {
self.imgCityIcon.image = UIImage(named: icon)
}
Note that you're using old syntax for some stuff:
For example UIViewAnimationOptions.curveEaseIn has been renamed to UIView.AnimationOptions.curveEaseIn. I would suggest you to start using newer versions of Swift

Answer 2

You need to implement an extension for UIView instead of NSObject.
since NSObject doesn't have any property like alpha you will get an
error.
Coding Example:
extension UIView {
func Fade (alphaOUT: Double,alphaIN: Double, input: Any) {
UIView.animate(withDuration: 1.0, delay: 0.0, options: UIView.AnimationOptions.curveEaseOut, animations: {
self.alpha = CGFloat(alphaOUT)
}, completion: {
(finished: Bool) -> Void in
// Fade in
UIView.animate(withDuration: 1.0, delay: 0.0, options: UIView.AnimationOptions.curveEaseIn, animations: {
self.alpha = CGFloat(alphaIN)
}, completion: nil)
})
}
}
class AnimationHelper {
class func Fade (alphaOUT: Double,alphaIN: Double, input: Any , yourLabel: UILabel, yourTextField: UITextField) {
UIView.animate(withDuration: 1.0, delay: 0.0, options: UIView.AnimationOptions.curveEaseOut, animations: {
yourLabel.alpha = CGFloat(alphaOUT)
yourTextField.alpha = CGFloat(alphaOUT)
}, completion: {
(finished: Bool) -> Void in
// Fade in
UIView.animate(withDuration: 1.0, delay: 0.0, options: UIView.AnimationOptions.curveEaseIn, animations: {
// Access your text field and label here.
}, completion: nil)
})
}
}