Programatically creating UIView in iOS || Swift

UIView

UIView is a rectangular area on mobile device screen, and the interface to managing the content in that area. At run time, a view object renders the content in that area and also handles the interactions with that content.

UIView object is the main responsible to handle all the user interface and also it is responsible to handle the following interaction

• Drawing and Animations

1. Views draw content in their rectangular area using technologies such as UIKit, Core Graphics and OpenGL ES.
2. And also it has some basic properties to animate the UIView from it's original values.

frame
bounds
center
transform
alpha
backgroundColor
contentStretch

• Layout and Sub-view management

1. A UIView may containts 0 or more subview

• Event handling

1. A UIView can response to the user interactions also by adding gestures to view object

Now let's create new xcode project to understand these things clearly. To create new xcode project open Xcode/New/Project/iOS/Appllication/Single view application.

Name your project and choose language as swift.

Let's go into coding part,

                

// 1) allocating and initilizing UIView object and adding it to ViewController's main container view

        let redView = UIView(frame: CGRect(x:20,y:50,width:self.view.frame.width-40,height:self.view.frame.height-50))

        self.view.addSubview(redView)

        

        // 2) specifies the view backgrount color by UIColor object

        redView.backgroundColor = UIColor.red

        

        

        // 3) handle layer properties of view object

        redView.layer.cornerRadius = 10

        redView.layer.masksToBounds = true

        redView.layer.borderColor = UIColor.green.cgColor

        redView.layer.borderWidth = 5

        

        // 4) animating uiview object

        let scaleAnimate:CABasicAnimation = CABasicAnimation(keyPath: "transform.scale")

        scaleAnimate.fromValue = 0

        scaleAnimate.toValue = 1

        scaleAnimate.duration = 5;

        scaleAnimate.repeatCount = 5

        scaleAnimate.autoreverses = true

        scaleAnimate.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut)

        redView.layer.add(scaleAnimate, forKey: "scaleNormalAnimation")

        

        

        //adding another view to the reView as it's sub-view

        let yellowView = UIView(frame: CGRect(x:10,y:10,width:redView.frame.width-20,height:redView.frame.height-20))

        redView.addSubview(yellowView)

        yellowView.backgroundColor = UIColor.yellow

Download demo code from here.