1首先在 AppDelegate.swift 中给控制器添加导航栏
// Created by Zin_戦 on 16/6/15.
// Copyright © 2016年 Zin戦壕. All rights reserved.
//
import UIKit
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
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.redColor()
self.window!.makeKeyAndVisible()
//创建一个控制器
let Vc = ViewController()
let NVc = UINavigationController(rootViewController:Vc)
self.window?.rootViewController = NVc
return true
}
2.接下来在ViewController里面
// Created by Zin_戦 on 16/6/15.
// Copyright © 2016年 Zin戦壕. All rights reserved.
//
import UIKit
class ViewController: UIViewController {
/*
懒加载格式：
lazy var 变量名:变量类型 = {
let 名字 = 变量类型()
return 名字
}()
*/
lazy var MyBtn : UIButton = {
let MyBtn = UIButton(frame:CGRectMake(150,150,50,50))
MyBtn.backgroundColor = UIColor.grayColor()
MyBtn.setTitle("跳转", forState: UIControlState.Normal)
MyBtn.addTarget(self, action: #selector(ViewController.MyBtnAction(_:)), forControlEvents: UIControlEvents.TouchUpInside)
return MyBtn
}()
lazy var MyLab:UILabel = {
let MyLab = UILabel(frame:CGRectMake(200,200,60,40))
MyLab.backgroundColor = UIColor.greenColor()
MyLab.text = "两颗草"
MyLab.adjustsFontSizeToFitWidth = true
return MyLab
}()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
view.addSubview(MyBtn)
view.addSubview(MyLab)
}
func MyBtnAction(btn:UIButton) {
print("按钮被点击了")
let secVc = SecondVC()
//闭包传值-3.实现闭包方法，并执行闭包
secVc.closure = {
(str:String) -> ()
in
self.MyLab.text = str
}
navigationController?.pushViewController(secVc, animated: true)
}
}
3.创建一个SecondVc
// Created by Zin_戦 on 16/6/15.
// Copyright © 2016年 Zin戦壕. All rights reserved.
//
import UIKit
class SecondVC: UIViewController {
//闭包生命1.声明闭包方法
var closure:((str:String) ->())?
//懒加载lab
lazy var lab : UILabel = {
var lab = UILabel(frame:CGRectMake(100,100,60,40))
lab.backgroundColor = UIColor.greenColor()
lab.text = "一颗草"
lab.adjustsFontSizeToFitWidth = true
return lab
}()
//懒加载Button
lazy var btn : UIButton =
{
let btn = UIButton(frame:CGRectMake(180,180,60,69))
btn.backgroundColor = UIColor.brownColor()
btn.setTitle("传值", forState: UIControlState.Normal)
btn.addTarget(self, action: #selector(SecondVC.btnAction(_:)), forControlEvents: UIControlEvents.TouchUpInside)
return btn
}()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = UIColor.whiteColor()
view.addSubview(lab)
view.addSubview(btn)
}
func btnAction(btn:UIButton) {
//闭包传值2.调用闭包传值
closure!(str:lab.text!)
navigationController?.popViewControllerAnimated(true)
}
}
tips：1.这里的闭包可以随便定义什么名字；
2.这里的懒加载固定的语法块，不要忘了{}()哦
/*
懒加载格式：
lazy var 变量名:变量类型 = {
let 名字 = 变量类型()
return 名字
}()
*/
3.总结闭包回传的步骤，类比block
1》在要把值传给另一个控制器的控制器（SecondVc）里声明闭包方法
2》在SecondVc里调用闭包传值
3》在FirstVc实现闭包方法，并执行闭包
