Swift iOS Code Recipes

Swift iOS Recipes

Swift iOS Recipes
==================

> https://github.com/JohnSundell/SwiftTips



** GUI Layout ** 
//Avoid Table view having Textfield covered by Keyboard 
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillShow), name: .UIKeyboardWillShow, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillHide), name: .UIKeyboardWillHide, object: nil)
        view.endEditing(true)
    }
    
    @objc func keyboardWillShow(_ notification: Notification) {
        let keyboardSize: CGSize? = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as AnyObject).cgRectValue?.size
        let animationDuration = (notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey]) as? CGFloat
        UIView.animate(withDuration: TimeInterval(animationDuration!), animations: {() -> Void in
            self.tableView.contentInset = UIEdgeInsetsMake(0.0, 0.0, (keyboardSize?.height)!, 0.0)
            self.tableView.scrollIndicatorInsets = UIEdgeInsetsMake(0.0, 0.0, (keyboardSize?.height)!, 0.0)
        })
    }
    
    @objc func keyboardWillHide(_ notification: Notification) {
        let animationDuration = (notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey]) as? CGFloat
        UIView.animate(withDuration: TimeInterval(animationDuration!), animations: {() -> Void in
            self.tableView.contentInset = UIEdgeInsets.zero
            self.tableView.scrollIndicatorInsets = UIEdgeInsets.zero
        })
    }
    
    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillShow, object: nil)
        NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillHide, object: nil)
    }
    
    
    ///End///
//DismissView - when dialog kind of presented and tapped out side of box. Target view usually the container/parent view of dialog.

   override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        
        if let touch = touches.first, !<target view>.bounds.contains(touch.location(in: <target view>)) {
             //do dismissal call
        }
    }


//Keyboard shows over textfield when dialog appears
//in viewDidLoad
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
	
	//Add these selectors
  @objc func keyboardWillShow(notification: NSNotification) {
        if !isKeyboardAppear {
            if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
                if self.view.frame.origin.y == 0{
                    self.view.frame.origin.y -= keyboardSize.height
                }
            }
            isKeyboardAppear = true
        }
    }
    
    @objc func keyboardWillHide(notification: NSNotification) {
        if isKeyboardAppear {
            if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
                if self.view.frame.origin.y != 0{
                    self.view.frame.origin.y += keyboardSize.height
                }
            }
            isKeyboardAppear = false
        }
    }
    

//Alerts

        var alert = UIAlertController(title: "Alert", message: "Message", preferredStyle: UIAlertControllerStyle.Alert)
        alert.addAction(UIAlertAction(title: "Click", style: UIAlertActionStyle.Default, handler: nil))
        self.presentViewController(alert, animated: true, completion: nil)

//Buttons on navigation

        let newButton = UIBarButtonItem(barButtonSystemItem: .Edit, target: self, action: "doSomething:")
        self.navigationItem.leftBarButtonItem = newButton


### Print as JSON by given Dictionary or [AnyHashable:Any]
       ``` 
	if let theJSONData = try? JSONSerialization.data(
                withJSONObject: <Your Dictionary>,
                options: [.prettyPrinted]) {
                let theJSONText = String(data: theJSONData,
                                         encoding: .ascii)
                print("JSON string = \(theJSONText!)")
            }
	 ```   
### for Objective-C : 
	
	```
	NSError *jerror;
        NSData *jsonData = [NSJSONSerialization dataWithJSONObject:responseData
                                                           options:NSJSONWritingPrettyPrinted // Pass 0 if you don't care about the readability of the generated string
                                                             error:&jerror];

        if (! jsonData) {
            NSLog(@"Got an error: %@", jerror);
        } else {
            NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
            NSLog(@"JSON >> %@", jsonString);
        }
	```

// Table View inside Table View Cell issue
// - Outer cell will not expand as per inner table view height.
// PS: Make InnerTableView scrolling false.

class InnerTableView: UITableView {
    override var intrinsicContentSize: CGSize {
        self.layoutIfNeeded()
        return self.contentSize
    }
    
    override var contentSize: CGSize {
        didSet{
            self.invalidateIntrinsicContentSize()
        }
    }
}



// Button Quick for test

		let button   = UIButton.buttonWithType(UIButtonType.System) as UIButton
	    button.frame = CGRectMake(100, 100, 100, 50)
	    button.backgroundColor = UIColor.greenColor()
	    button.setTitle("Test Button", forState: UIControlState.Normal)
	    button.addTarget(self, action: "buttonAction:", forControlEvents: UIControlEvents.TouchUpInside)

		button.layer.cornerRadius = 5
		button.layer.borderWidth = 1
		button.layer.borderColor = UIColor.blackColor().CGColor
			    
	    self.view.addSubview(button)

	    func buttonAction(sender:UIButton!) {
	    //do something
	    }	    

// Quick Label creation for test

        newLabel = UILabel(frame: CGRect(x: 20, y: 10, width: 300, height: 200))
        newLabel.text = "Tap and hold for settings"
        newLabel.textColor = UIColor.whiteColor()
        newLabel.textAlignment = NSTextAlignment.Center
        newLabel.font = UIFont(name: "HelveticaNeue", size: CGFloat(17))

// Slider

        var slider = UISlider(frame: CGRectMake(0, 0, 300, 200))
        slider.addTarget(self, action: "changeSomething:", forControlEvents: UIControlEvents.ValueChanged)
        slider.backgroundColor = UIColor.blackColor()
        slider.minimumValue = 0.0
        slider.maximumValue = 1.0
        slider.continuous = true
        slider.value = 0.5
        self.view.addSubview(slider)

        func changeSomething(sender:UISlider!) {
            self.someValue = sender.value
        }


//Dimensions

		var screenSize: CGRect = UIScreen.mainScreen().bounds

//Collection View

        let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout()
        layout.sectionInset = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
        layout.itemSize = CGSize(width: 120, height: 90)

		collectionView = UICollectionView(frame: self.view.frame, collectionViewLayout: layout)
        collectionView!.dataSource = self
        collectionView!.delegate = self
        collectionView!.registerClass(UICollectionViewCell.self, forCellWithReuseIdentifier: reuseIdentifier)
        collectionView!.backgroundColor = UIColor.blackColor()
        self.view.addSubview(collectionView!)

//Table View

        tableView = UITableView(frame: self.view.frame, style: .Plain)
        self.view.addSubview(tableView)
        tableView.delegate = self
        tableView.dataSource = self
        tableView.registerClass(UITableViewCell.self, forCellReuseIdentifier: cellIdentifier)        

//Image View
	
		var frame = self.view.frame
        someImage = UIImageView(frame: CGRect(x: 0, y: 0, width: frame.size.width, height: frame.size.height))


//Transitions

	Pushes

        let vc = SettingsViewController()
        self.navigationController?.pushViewController(vc, animated: true)

    Segues (have to use IB to set up segue identifiers)


//Constraints with Masonry Snap

        let padding = UIEdgeInsetsMake(10, 10, 10, -50)
        let superview = self.view
        
        someView.snp_makeConstraints { make in
            make.top.equalTo(superview.snp_top).with.offset(padding.top)
            make.left.equalTo(superview.snp_left).with.offset(padding.left)
        }


/** GUI Events **
//Gray Activity Indicator View

        var activityIndicatorView = UIActivityIndicatorView(activityIndicatorStyle: .Gray)
        view.addSubview(activityIndicatorView)
        activityIndicatorView.center = view.center
        activityIndicatorView.startAnimating()

        activityIndicatorView.removeFromSuperview()

//Touches

        press = UILongPressGestureRecognizer(target: self, action: "doSomething:")
        press.minimumPressDuration = 0.5
        press.numberOfTapsRequired = 0
        press.numberOfTouchesRequired = 1
        press.delegate = self
        self.view.addGestureRecognizer(press)


//Notifications

        NSNotificationCenter.defaultCenter().addObserver(
            self,
            selector: "doSomething:",
            name: someKey,
            object: nil)

		func doSomething(notification: NSNotification) {	        
	    }

//App Delegate setup

        let rootViewController = SomeViewController()
        let frame = UIScreen.mainScreen().bounds
        self.window = UIWindow(frame: frame)
        let navController = UINavigationController(rootViewController: rootViewController)
        self.window?.rootViewController = navController
        self.window?.backgroundColor = UIColor.whiteColor()
        self.window?.makeKeyAndVisible()

//Delegates

		protocol NewDelegate {
		    func doSomething()
		}

		In class:

			var delegate: NewDelegate?

			self.delegate?.doSomething()

		In target class:

			Inherit from NewDelegate
			newObject.delegate = self
			Implement the protocol methods


	
	// ****** Loads Xib/nib from project as uiviewcontroller ****/
	extension UIViewController {
    	static func loadFromNib() -> Self {
        func instantiateFromNib<T: UIViewController>() -> T {
            return T.init(nibName: String(describing: T.self), bundle: nil)
        }

        return instantiateFromNib()
    	}
	}
	
	/*****Loads ViewController by all ways : ***/
	
extension UIViewController {
    
    static func instantiate<TController: UIViewController>(_ storyboardName: String) -> TController {
        return instantiateFromStoryboardHelper(storyboardName)
    }
    
    static func instantiate<TController: UIViewController>(_ storyboardName: String, identifier: String) -> TController {
        return instantiateFromStoryboardHelper(storyboardName, identifier: identifier)
    }
    
    fileprivate static func instantiateFromStoryboardHelper<T: UIViewController>(_ name: String, identifier: String? = nil) -> T {
        let storyboard = UIStoryboard(name: name, bundle: Bundle(for: self))
        return storyboard.instantiateViewController(withIdentifier: identifier ?? String(describing: self)) as! T
    }
    
    static func instantiate<TController: UIViewController>(xibName: String? = nil) -> TController {
        return TController(nibName: xibName ?? String(describing: self), bundle: Bundle(for: self))
    }
}
/ ***** End Load a ViewController ***** /
 

extension String {

      func replaceOccuranceOfSpaceInURLString() -> String {
         return self.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed) ?? self
      }
    
      var boolValue: Bool {
          return (self as NSString).boolValue
      }
      
     var isBackSpace:Bool {
        let char = self.cString(using: String.Encoding.utf8)!
        let isBackSpace = strcmp(char, "\\b")
        return isBackSpace == -92
    }
  }


// Storing a property in a class using Static property.
extension UIView {

    struct Holder {
        static var _padding:[UIView:UIEdgeInsets] = [:]
    }

    var padding : UIEdgeInsets {
        get{ return UIView.Holder._padding[self] ?? .zero}
        set { UIView.Holder._padding[self] = newValue }
    }

}


//Button Extension that makes button with icon at top 
// -----[image]-----------
// ----title of button----
// -----------------------
extension UIButton {

    func centerVertically(padding: CGFloat = 6.0) {
        guard
            let imageViewSize = self.imageView?.frame.size,
            let titleLabelSize = self.titleLabel?.frame.size else {
            return
        }

        let totalHeight = self.bounds.size.height

        self.imageEdgeInsets = UIEdgeInsets(
            top: max(0, -(totalHeight - imageViewSize.height)),
            left: 0.0,
            bottom: 0.0,
            right: -titleLabelSize.width
        )

        self.titleEdgeInsets = UIEdgeInsets(
            top: 0.0,
            left: -imageViewSize.width,
            bottom: -(totalHeight - titleLabelSize.height),
            right: 0.0
        )

        self.contentEdgeInsets = UIEdgeInsets(
            top: 0.0,
            left: 0.0,
            bottom: titleLabelSize.height,
            right: 0.0
        )
    }
}

//Extension - shortcut to add child vc 
extension UIViewController {
    func add(_ child: UIViewController) {
        addChild(child)
        view.addSubview(child.view)
        child.didMove(toParent: self)
    }

    func remove() {
        // Just to be safe, we check that this view controller
        // is actually added to a parent before removing it.
        guard parent != nil else {
            return
        }

        willMove(toParent: nil)
        view.removeFromSuperview()
        removeFromParent()
    }
}

    let networkInfo = CTTelephonyNetworkInfo()
    let carrierTypeString = networkInfo.serviceCurrentRadioAccessTechnology!.values.first!
    switch carrierTypeString {
    case CTRadioAccessTechnologyGPRS,CTRadioAccessTechnologyEdge,CTRadioAccessTechnologyCDMA1x: return "2G"
    case CTRadioAccessTechnologyWCDMA,CTRadioAccessTechnologyHSDPA,CTRadioAccessTechnologyHSUPA,CTRadioAccessTechnologyCDMAEVDORev0,CTRadioAccessTechnologyCDMAEVDORevA,CTRadioAccessTechnologyCDMAEVDORevB,CTRadioAccessTechnologyeHRPD: return "3G"
    case CTRadioAccessTechnologyLTE: return "4G"
    default: return ""