byJeevan · May 31, 2020 12:52 · byJeevan · Sep 14, 2018 · byJeevan · Nov 6, 2018
diff --git a/Swift3.1 CheatSheet Plus b/Swift3.1 CheatSheet Plus

 /*
 * Author  : Jeevan Rao
 * Date    : 13/0/2017 
 * Swift   : V3.1
 */
 
 /* UI + UX Tricks */
 //Selection style of table view cell (other than Default grey / Blue/ none)
        let selectionColorView = UIView()
        selectionColorView.backgroundColor = UIColor.blue
        cell.selectedBackgroundView = selectionColorView
  
 //UISeachBar Cancel button color
 UIBarButtonItem.appearance(whenContainedInInstancesOf:[UISearchBar.self]).tintColor = UIColor.white

 //Slowdown UI Updates
    func delay(_ delay:Double, closure:@escaping ()->()) {
        let when = DispatchTime.now() + delay
        DispatchQueue.main.asyncAfter(deadline: when, execute: closure)
    }
    
 /* Extensions */

 //Bottom border for text field
 extension UITextField
 {
    //Bottom line/border for UITextfield
    func setBottomBorderColor(_ color:UIColor)
    {
        self.borderStyle = .none;
        let border = CALayer()
        let width = CGFloat(1.0)
        border.borderColor = color.cgColor
        border.frame = CGRect(x: 0, y: self.frame.size.height - width,   width:  self.frame.size.width, height: self.frame.size.height)
        border.borderWidth = width
        self.layer.addSublayer(border)
        self.layer.masksToBounds = true
    }
 }

 //Shadow - card effect for UIView
 extension UIView {
    func addDropShadowToView(){
        self.layer.masksToBounds = false
        self.layer.shadowColor = UIColor.gray.cgColor;
        self.layer.shadowOffset = CGSize(width:2.0, height:2.0)
        self.layer.shadowOpacity = 0.75
    }
 }

 // Make ‘String’ to return its Length
 extension String {
    var length: Int {
        return (self as NSString).length
    }
 }

 //Will return NSAttributedString from HTML String
 extension String{
    func convertHtml() -> NSAttributedString{
        guard let data = data(using: .utf8) else { return NSAttributedString() }
        do{
            return try NSAttributedString(data: data, options: [NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType, NSCharacterEncodingDocumentAttribute: String.Encoding.utf8.rawValue], documentAttributes: nil)
        }catch{
            return NSAttributedString()
        }
    }
 }
 myLabel.attributedText = "<b>Bolded</b>".convertHtml() //Example

 //Gives array of unique elements from given array
 extension Sequence where Iterator.Element: Hashable {
    func unique() -> [Iterator.Element] {
        var seen: [Iterator.Element: Bool] = [:]
        return self.filter { seen.updateValue(true, forKey: $0) == nil }
    }
 }


 /* Misc */

 //Calculates execution time of block of code.
            let info = ProcessInfo.processInfo
            let begin = info.systemUptime
            //Code Stuff
            let diff = (info.systemUptime - begin)


 //List all the installed Fonts 

        for fontFamilyName in UIFont.familyNames{
            for fontName in UIFont.fontNames(forFamilyName: fontFamilyName){
                print("Family: \(fontFamilyName)     Font: \(fontName)")
            }
        }
        
    
 //RESET User Defaults (all keys)
        let domain = Bundle.main.bundleIdentifier!
        UserDefaults.standard.removePersistentDomain(forName: domain)
        UserDefaults.standard.synchronize()

 //Generate UIImage object from UIView
   func generateImage(for view: UIView) -> UIImage? {
        defer {
            UIGraphicsEndImageContext()
        }
        UIGraphicsBeginImageContextWithOptions(view.bounds.size, false, UIScreen.main.scale)
        if let context = UIGraphicsGetCurrentContext() {
            view.layer.render(in: context)
            return UIGraphicsGetImageFromCurrentImageContext()
        }
        return nil
    }
    
    //:usage 
      var iconWithTextImage: UIImage {
        let containerView = UIView.init(frame: CGRect(x: 0, y: 0, width: 30, height: 30))
        let icon = UIImageView.init(frame: CGRect(x: 0, y: 0, width: 30, height: 30))
        icon.image = UIImage.init(named: "shirt.png")
        icon.contentMode = .scaleAspectFit
        containerView.addSubview(icon)
        return generateImage(for: containerView) ?? UIImage()
    }
    
 //CLOSURE Callback Example 
 //Closure Callback : 
 public typealias Closure = () -> Void

 //Definition
 public var exitFromTap  = Closure?({})

 //Declaration in somewhere needs a callback.
 exitFromTap?()

 //Usage
 yourClass.exitFromTap = {    print(“Good Bye”)     }

 /// Returns the element at the specified index iff it is within bounds, otherwise nil.
 extension Collection {
    subscript (safe index: Index) -> Element? {
        return indices.contains(index) ? self[index] : nil
    }
 }


 let sample = ["BMW", "Audi", "Tesla", "Fiat"]
 sample[safe : 0] //Prints "BMW"
 sample[safe : 4] //Prints 'nil'


diff --git a/Swift4 Cheetsheet Plus b/Swift4 Cheetsheet Plus
 /// String extension : replacement for' subString:'
   extension String {
     func slice(from: String, to: String) -> String? {
        
        let fromIndex = self.index(self.index(of: from)!, offsetBy: 1)
        let toIndex = self.index(self.index(of: to)!, offsetBy: -1)
        
        return String(self[fromIndex...toIndex])
     }
   }
 //Usage : "Date(1511508780012+0530)".slice(from: "(", to: "+")
 

 //Core Data - Easy & Clean way to get NSManagedContext  

   public static func getContext() -> NSManagedObjectContext {
        let appDelegate = UIApplication.shared.delegate as! AppDelegate
        return appDelegate.persistentContainer.viewContext
    }

 //Limit characters in text filed
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        
        let currentCharacterCount = textField.text?.count ?? 0
        if (range.length + range.location > currentCharacterCount){
            return false
        }
        let newLength = currentCharacterCount + string.count - range.length
        return newLength <= Constants.nameCharLimit
    }

	/*
	* Author : Jeevan Rao
	* Date : 13/0/2017
	* Swift : V3.1
	*/

	/* UI + UX Tricks */
	//Selection style of table view cell (other than Default grey / Blue/ none)
	let selectionColorView = UIView()
	selectionColorView.backgroundColor = UIColor.blue
	cell.selectedBackgroundView = selectionColorView

	//UISeachBar Cancel button color
	UIBarButtonItem.appearance(whenContainedInInstancesOf:[UISearchBar.self]).tintColor = UIColor.white

	//Slowdown UI Updates
	func delay(_ delay:Double, closure:@escaping ()->()) {
	let when = DispatchTime.now() + delay
	DispatchQueue.main.asyncAfter(deadline: when, execute: closure)
	}

	/* Extensions */

	//Bottom border for text field
	extension UITextField
	{
	//Bottom line/border for UITextfield
	func setBottomBorderColor(_ color:UIColor)
	{
	self.borderStyle = .none;
	let border = CALayer()
	let width = CGFloat(1.0)
	border.borderColor = color.cgColor
	border.frame = CGRect(x: 0, y: self.frame.size.height - width, width: self.frame.size.width, height: self.frame.size.height)
	border.borderWidth = width
	self.layer.addSublayer(border)
	self.layer.masksToBounds = true
	}
	}

	//Shadow - card effect for UIView
	extension UIView {
	func addDropShadowToView(){
	self.layer.masksToBounds = false
	self.layer.shadowColor = UIColor.gray.cgColor;
	self.layer.shadowOffset = CGSize(width:2.0, height:2.0)
	self.layer.shadowOpacity = 0.75
	}
	}

	// Make ‘String’ to return its Length
	extension String {
	var length: Int {
	return (self as NSString).length
	}
	}

	//Will return NSAttributedString from HTML String
	extension String{
	func convertHtml() -> NSAttributedString{
	guard let data = data(using: .utf8) else { return NSAttributedString() }
	do{
	return try NSAttributedString(data: data, options: [NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType, NSCharacterEncodingDocumentAttribute: String.Encoding.utf8.rawValue], documentAttributes: nil)
	}catch{
	return NSAttributedString()
	}
	}
	}
	myLabel.attributedText = "<b>Bolded</b>".convertHtml() //Example

	//Gives array of unique elements from given array
	extension Sequence where Iterator.Element: Hashable {
	func unique() -> [Iterator.Element] {
	var seen: [Iterator.Element: Bool] = [:]
	return self.filter { seen.updateValue(true, forKey: $0) == nil }
	}
	}


	/* Misc */

	//Calculates execution time of block of code.
	let info = ProcessInfo.processInfo
	let begin = info.systemUptime
	//Code Stuff
	let diff = (info.systemUptime - begin)


	//List all the installed Fonts

	for fontFamilyName in UIFont.familyNames{
	for fontName in UIFont.fontNames(forFamilyName: fontFamilyName){
	print("Family: \(fontFamilyName) Font: \(fontName)")
	}
	}


	//RESET User Defaults (all keys)
	let domain = Bundle.main.bundleIdentifier!
	UserDefaults.standard.removePersistentDomain(forName: domain)
	UserDefaults.standard.synchronize()

	//Generate UIImage object from UIView
	func generateImage(for view: UIView) -> UIImage? {
	defer {
	UIGraphicsEndImageContext()
	}
	UIGraphicsBeginImageContextWithOptions(view.bounds.size, false, UIScreen.main.scale)
	if let context = UIGraphicsGetCurrentContext() {
	view.layer.render(in: context)
	return UIGraphicsGetImageFromCurrentImageContext()
	}
	return nil
	}

	//:usage
	var iconWithTextImage: UIImage {
	let containerView = UIView.init(frame: CGRect(x: 0, y: 0, width: 30, height: 30))
	let icon = UIImageView.init(frame: CGRect(x: 0, y: 0, width: 30, height: 30))
	icon.image = UIImage.init(named: "shirt.png")
	icon.contentMode = .scaleAspectFit
	containerView.addSubview(icon)
	return generateImage(for: containerView) ?? UIImage()
	}

	//CLOSURE Callback Example
	//Closure Callback :
	public typealias Closure = () -> Void

	//Definition
	public var exitFromTap = Closure?({})

	//Declaration in somewhere needs a callback.
	exitFromTap?()

	//Usage
	yourClass.exitFromTap = { print(“Good Bye”) }

	/// Returns the element at the specified index iff it is within bounds, otherwise nil.
	extension Collection {
	subscript (safe index: Index) -> Element? {
	return indices.contains(index) ? self[index] : nil
	}
	}


	let sample = ["BMW", "Audi", "Tesla", "Fiat"]
	sample[safe : 0] //Prints "BMW"
	sample[safe : 4] //Prints 'nil'
	/// String extension : replacement for' subString:'
	extension String {
	func slice(from: String, to: String) -> String? {

	let fromIndex = self.index(self.index(of: from)!, offsetBy: 1)
	let toIndex = self.index(self.index(of: to)!, offsetBy: -1)

	return String(self[fromIndex...toIndex])
	}
	}
	//Usage : "Date(1511508780012+0530)".slice(from: "(", to: "+")


	//Core Data - Easy & Clean way to get NSManagedContext

	public static func getContext() -> NSManagedObjectContext {
	let appDelegate = UIApplication.shared.delegate as! AppDelegate
	return appDelegate.persistentContainer.viewContext
	}

	//Limit characters in text filed
	func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {

	let currentCharacterCount = textField.text?.count ?? 0
	if (range.length + range.location > currentCharacterCount){
	return false
	}
	let newLength = currentCharacterCount + string.count - range.length
	return newLength <= Constants.nameCharLimit
	}