Some Usefull extensions in Swift

Extensions in Swift

When we use extensions in swift it saves our lot of code by just few lines of code and also improves your code structure. Extensions are those you can write your function in default classes of iOS Useful extensions are :-

• Apply Border in your view :- If you want to use border in your whole it must be same in your whole app. You must create extension of border so if you want to change the size or colour of border it will automatically reflect in your whole application.
  
  extension UIView { func applyBorder() -> Void { self.layer.borderColor = UIColor.black.cgColor // change yor color self.layer.borderWidth = 1.5 self.layer.shadowColor = UIColor.black.cgColor self.layer.shadowOffset = CGSize(width: 1.0, height: 1.0) } } // or pass color while using this function extension UIView { func applyBorder(colours: UIColor) -> Void { self.layer.borderColor = colours.cgColor self.layer.borderWidth = 1.5 self.layer.shadowColor = UIColor.black.cgColor self.layer.shadowOffset = CGSize(width: 1.0, height: 1.0) } }

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  extension UIView {     func applyBorder() -> Void {         self.layer.borderColor = UIColor.black.cgColor // change yor color         self.layer.borderWidth = 1.5         self.layer.shadowColor = UIColor.black.cgColor         self.layer.shadowOffset = CGSize(width: 1.0, height: 1.0)     } }   // or pass color while using this function   extension UIView {     func applyBorder(colours: UIColor) -> Void {         self.layer.borderColor = colours.cgColor         self.layer.borderWidth = 1.5         self.layer.shadowColor = UIColor.black.cgColor         self.layer.shadowOffset = CGSize(width: 1.0, height: 1.0)     } }

  
  How to use :-
  
  yourView.applyBorder() // or yourView.applyBorder(colours: UIColor.green)

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  yourView.applyBorder()   // or   yourView.applyBorder(colours: UIColor.green)

  
   
• Remove String :- Lots of time happen you want to remove substring from string,Its more irritating to use again and again replacingOccurrences function.So its better create the extension of removing string.
  
  extension String { func removeString(completeString:String , remove: String) -> String { let aString = completeString let newString = aString.replacingOccurrences(of: "", with: remove, options: .literal, range: nil) return newString } }

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  extension String {     func removeString(completeString:String , remove: String) -> String {         let aString = completeString         let newString = aString.replacingOccurrences(of: "", with: remove, options: .literal, range: nil)         return newString     } }

  
  How to use :-
  
  let name = string.removeString(completeString:"abcdef" , remove: "def") output is name = "abc"

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  let name = string.removeString(completeString:"abcdef" , remove: "def")   output is   name = "abc"

• Set image and download image :- In almost every application you have to downloads the images from string. I strongly recommend use the Kingfisher library for downloading images from server ( https://github.com/onevcat/Kingfisher ) and caching images. So its better to create the extension of  UIImageView then create the function in UIImageView class where you can download the images and cache the images and also sets the placeholder while dowloading the images.
  
  import Kingfisher extension UIImageView { func setImage(imageUrl : String? ) { if URL(string: imageUrl) != nil && imageUrl.count > 0 { let resource = ImageResource(downloadURL: URL(string: imageUrl)!, cacheKey: imageUrl) self.contentMode = .scaleAspectFit self.kf.setImage(with: resource, placeholder: UIImage(named : "placeholder") , options: nil, progressBlock: nil, completionHandler: nil) } else{ self.image = UIImage(named : "placeholder") } } }

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  import Kingfisher   extension UIImageView {          func setImage(imageUrl : String? ) {           if URL(string: imageUrl) != nil && imageUrl.count > 0 {             let resource = ImageResource(downloadURL: URL(string: imageUrl)!, cacheKey: imageUrl)             self.contentMode = .scaleAspectFit             self.kf.setImage(with: resource, placeholder: UIImage(named : "placeholder") , options: nil, progressBlock: nil, completionHandler: nil)         }         else{             self.image = UIImage(named : "placeholder")         }     } }

  
  How to use it :-
  
  yourImage.setImage(imageUrl: ImageUrl) //set your image to UIImageView

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  yourImage.setImage(imageUrl: ImageUrl)   //set your image to UIImageView

  
   
• Width and height of string :- if you want to find the width and height of string use this function .
  
  extension String { func widthOfString(usingFont font: UIFont) -> CGFloat { let fontAttributes = [NSFontAttributeName: font] let size = self.size(attributes: fontAttributes) return size.width } func heightOfString(usingFont font: UIFont) -> CGFloat { let fontAttributes = [NSFontAttributeName: font] let size = self.size(attributes: fontAttributes) return size.height } }

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  extension String {          func widthOfString(usingFont font: UIFont) -> CGFloat {         let fontAttributes = [NSFontAttributeName: font]         let size = self.size(attributes: fontAttributes)         return size.width     }          func heightOfString(usingFont font: UIFont) -> CGFloat {         let fontAttributes = [NSFontAttributeName: font]         let size = self.size(attributes: fontAttributes)         return size.height     } }

  
  How to use it :-
  
  let stringSize = buttonText.widthOfString(usingFont: UIFont.systemFont(ofSize: 14))

  1	let stringSize = buttonText.widthOfString(usingFont:  UIFont.systemFont(ofSize: 14))

  
   
• Load XIB :- xib’s play important role in iOS application you use many times or almost in each page of application. So create the extension of Bundle where you can load your xib.
  
  extension Bundle { static func loadView<T>(fromNib name: String, withType type: T.Type) -> T { if let view = Bundle.main.loadNibNamed(name, owner: nil, options: nil)?.first as? T { return view } fatalError("Could not load view with type " + String(describing: type)) } }

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  extension Bundle {          static func loadView<T>(fromNib name: String, withType type: T.Type) -> T {         if let view = Bundle.main.loadNibNamed(name, owner: nil, options: nil)?.first as? T {             return view         }                  fatalError("Could not load view with type " + String(describing: type))     } }

  
  How to use it :-
  
  var emptyView : EmptyView? // your xib emptyView = Bundle.loadView(fromNib: "EmptyView", withType: EmptyView.self) // it will load your xib

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  var emptyView : EmptyView? // your xib emptyView = Bundle.loadView(fromNib: "EmptyView", withType: EmptyView.self) // it will load your xib