swift篇第四期:闭包、UI基础、Protocol
首先来讲下闭包吧,其实闭包跟之前C中的block回调函数类似,但这里只研究了基础的使用,我在下面的两个VC中利用闭包做了通讯传值,也算是比较常用的方法吧,回头有时间我再研究下在项目中的其它应用
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let sayHello = { println("nihao") } sayHello() //定义一个闭包函数,与常规方法不同的是后面有个关键字in哦 let add = { (a: Int, b: Int) -> Int in return a + b } //调用的时候其实跟调用方法一样哦 println(add(1, 2)) //下面就是一个简单的例子,来找出数组中大于等于value的值,如果有,返回Yes var array = [20, 9, 100, 34, 89, 39] func hasClosureMatch(array: [Int], value: Int, closureValue: (num:Int, value:Int)-> Bool)-> Bool { for item in array { if (closureValue(num: item, value: value)) { return true } } return false } //Closure 闭包 var v1 = hasClosureMatch(array, 40) { (num, value) -> Bool in return num >= value } println(v1)
然后是UI基础的代码,可以直接创建单一控制器的工程,主要是为了熟悉一下代码
这里我们可以先把storyboard关掉,直接改动appdelegate里面的方法
UI这里面就没有太多要讲的,主要是多查查相关的API,然后慢慢积累咯
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { // Override point for customization after application launch. self.window = UIWindow(frame: UIScreen.mainScreen().bounds) self.window!.backgroundColor = UIColor.whiteColor() self.window!.makeKeyAndVisible() //从语法上,我觉得跟O-C真的很不一样,但是道理是通的,如果你的O-C语言还算熟练,我想上手swift语言也是很轻松的 let rootViewController = RootViewController() let navigationController = UINavigationController(rootViewController: rootViewController) navigationController.tabBarItem = UITabBarItem(title: "第一页", p_w_picpath: nil, tag: 1) let secondViewController = SecondViewController() let secondNavigationController = UINavigationController(rootViewController: secondViewController) secondNavigationController.tabBarItem = UITabBarItem(title: "第二页", p_w_picpath: nil, tag: 2) let array = [navigationController, secondNavigationController]; let tabBarController = UITabBarController() tabBarController.viewControllers = array self.window!.rootViewController = tabBarController return true }
接下来我们创建两个VC的类,Swift里面并没有所谓的指定类创建,而是在swift文件里,我们可以创建好多好多的类,当然了,为了更好的区分,我就单独创建类吧
这样我们在两个类里面单独创建一些基础的控件,然后再写一个协议来运用起来
主要还算来熟悉一下相关的语法
在下面的代码中也用到了Protocol以及Closure,方便小伙伴们上手哦
class RootViewController: UIViewController, ViewChangeDelegate { var clickCount:Int = 0; var myLabel:UILabel? override func viewDidLoad() { super.viewDidLoad() self.title = "炉石传说" let nextItem = UIBarButtonItem(title: "下一页", style: .Plain, target: self, action: "nextPage:") self.navigationItem.rightBarButtonItem = nextItem myLabel = UILabel(frame: CGRect(x: 0, y: 100, width: 320, height: 44)) myLabel!.text = "小华,你好啊" myLabel!.backgroundColor = UIColor.redColor() self.view.addSubview(myLabel!) var myButton = UIButton(frame: CGRect(x: 100, y: 200, width: 100, height: 44)) myButton.backgroundColor = UIColor.blueColor() myButton.setTitle("点击", forState: .Normal) myButton.addTarget(self, action: "clickMe:", forControlEvents: .TouchUpInside) self.view.addSubview(myButton) } func clickMe(sender:UIButton) { clickCount += 1; println("click\(clickCount)") myLabel!.text = "你猜我点了几次呢,\(clickCount)" } func nextPage(sender:UIButton) { let secondViewController = SecondViewController() secondViewController.viewChangeDelegate = self secondViewController.changeTextForClosure("1", num: 1) { (value, num) -> Void in myLabel?.text = value } self.navigationController?.pushViewController(secondViewController, animated: true) } func changeTitleToString(controller:UIViewController, value:String) { myLabel!.text = value }
import Foundation import UIKit class SecondViewController: UIViewController { var viewChangeDelegate:ViewChangeDelegate? var closure = { (value:String, num:Int) -> Void in } override func viewDidLoad() { super.viewDidLoad() self.title = "第二页" self.view.backgroundColor = UIColor.grayColor() var button = UIButton.buttonWithType(.System) as! UIButton button.frame = CGRect(x: 100, y: 100, width: 100, height: 40) button.setTitle("返回上一页", forState: .Normal) button.addTarget(self, action: "back:", forControlEvents: .TouchUpInside) self.view.addSubview(button) var buttonChange = UIButton.buttonWithType(.System) as! UIButton buttonChange.frame = CGRect(x: 100, y: 200, width: 100, height: 40) buttonChange.setTitle("改变首页label值", forState: .Normal) buttonChange.addTarget(self, action: "change:", forControlEvents: .TouchUpInside) self.view.addSubview(buttonChange) } func changeTextForClosure(value:String, num:Int, closureValue:(value:String, num:Int) -> Void) { self.closure = closureValue } func change(sender:UIButton) { if ((viewChangeDelegate) != nil) { viewChangeDelegate?.changeTitleToString(self, value: "我变变变") } self.closure("你好", 1) } func back(sender:UIButton) { self.navigationController?.popToRootViewControllerAnimated(true) } } protocol ViewChangeDelegate : NSObjectProtocol { func changeTitleToString(controller:UIViewController, value:String) }
好啦,就先写这么多吧
名称栏目:swift篇第四期:闭包、UI基础、Protocol
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