IOS移动开发从入门到精通 视图UIView、层CALayer(1)

UIView是UIKit框架里面最基础的视图类。UIView类定义了一个矩形的区域，并管理该矩形区域内的所有屏幕显示。

控件

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1个UIWindow 或 UIView 1、设置背景色 import UIKit class ViewController：UIViewController { override func viewDidLoad() { super.viewDidLoad() // Do any additional setup after loading the view,typically from a nib. let view = UIView(frame：CGRect(x：40, y：80,width：240, height：240)) view.backgroundColor = UIColor.black view.clipsToBounds=true self.view.addSubview(view) } override func didReceiveMemoryWarning() { super.didReceiveMemoryWarning() // Dispose of any resources that can be recreated. } }

以图片做背景

let view = UIView(frame：CGRect(x：40, y：80,width：240, height：240)) let image = UIImage(named：“Sample”) view.backgroundColor = UIColor.init(patternImage:image！) self.view.addSubview(view)

修改不透明度 view.alpha = 0.3

是否隐藏 view.isHidden=true

是否交互 userInteractionEnabled

设置边框：

view.layer.borderWidth = 20 view.layer.borderColor = UIColor.lightGray.cgColor

设置阴影：

view.layer.shadowColor = UIColor.black.cgColor view.layer.shadowOffset = CGSize(width：10.0,height：10.0) view.layer.shadowOpacity = 0.45 view.layer.shadowRadius = 5.0

设置圆角：view.layer.cornerRadius = 40

捕获用户触摸事件UITapGestureRecognizer(taget:self,action:#selector(ViewController.SingleTap))

import UIKit class ViewController：UIViewController { override func viewDidLoad() { super.viewDidLoad() // Do any additional setup after loading the view,typically from a nib. let touchView = UIView(frame：CGRect(x：60, y：60,width：200, height：200)) touchView.backgroundColor = UIColor.black self.view.addSubview(touchView) let guesture = UITapGestureRecognizer(target：self,action：#selector(ViewController.SingleTap)) touchView.addGestureRecognizer(guesture) } func SingleTap() { print(“You touched me.”) } override func didReceiveMemoryWarning() { super.didReceiveMemoryWarning() // Dispose of any resources that can be recreated. } }

使用自定义视图:新建Swift File

import UIKit class RoundView:UIView { var color = UIColor.blue override init(frame:CGRect) { super.init(frame:frame) self.backgroundColor = UIColor.clear } override func draw(_ rect：CGRect) { let ctx = UIGraphicsGetCurrentContext() ctx?.clear(self.frame) ctx?.setFillColor(color.cgColor) ctx?.fillEllipse(in:CGRect(x:0, y:0, width:self.frame.width, height:self.frame.height)) } required init?(coder aDecoder:NSCoder) { fatalError("init(coder:) has not been implemented") } }

在ViewController中调用

import UIKit class ViewController：UIViewController { override func viewDidLoad() { super.viewDidLoad() // Do any additional setup after loading the view,typically from a nib. let view = RoundView(frame：CGRect(x：40, y：40,width：240, height：240)) self.view.addSubview(view) } override func didReceiveMemoryWarning() { super.didReceiveMemoryWarning() // Dispose of any resources that can be recreated. } }

设置渐变view

let rect = CGRect(x：20, y：60, width：240, height：240) let gradientView = UIView(frame：rect) let gradientLayer = CAGradientLayer() gradientLayer.frame = gradientView.frame let fromColor = UIColor.yellow.cgColor let midColor = UIColor.blue.cgColor let toColor = UIColor.red.cgColor gradientLayer.colors = [fromColor, midColor, toColor] gradientLayer.startPoint = CGPoint(x：0, y：0) gradientLayer.endPoint = CGPoint(x：1, y：1) gradientLayer.locations = [0, 0.3, 1] gradientView.layer.addSublayer(gradientLayer) self.view.addSubview(gradientView)

仿射变换：旋转，缩小，扩大等

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视图嵌套

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