首先呢说下结构
一个ViewController
一个ModelViewController
在ModelViewController中定义了一个协议
这个逻辑 从第一个界面进入第二个界面 从第二个界面回到第二个界面并通过协议传值回到第一个界面 打印输出值
ModelViewController.swift
protocol lwkDelegate {//定义协议
func changeString(newString:String)
}
在这个ModelViewControler类中实现一些简单的逻辑
class ModelViewController: UIViewController{
var delegate:lwkDelegate?
var btn:UIButton?
override func viewDidLoad() {
super.viewDidLoad()
btn=UIButton(frame:CGRectMake(110,80,100,20))
btn!.backgroundColor=UIColor.grayColor()
btn!.setTitle("传值回第一个界面",forState:.Normal)
//绑定事件
btn!.addTarget(self,action:#selector(ModelViewController.btnOnClick),forControlEvents: UIControlEvents.TouchUpInside)
self.view.addSubview(btn!)
}
func btnOnClick(){
let str:String = "liuweikai"
delegate!.changeString(str)//调用协议方法
self.dismissViewControllerAnimated(true, completion: nil)
}
在ViewController类中
class ViewController: UIViewController,lwkDelegate{//接受协议
var btn:UIButton?
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
btn=UIButton(frame:CGRectMake(110,80,100,20))
btn!.backgroundColor=UIColor.greenColor()
btn!.setTitle("去二个界面",forState:.Normal)
//绑定事件
btn!.addTarget(self,action:#selector(ViewController.btnOnClick),forControlEvents: UIControlEvents.TouchUpInside)
self.view.addSubview(btn!)
}
func btnOnClick(){
let vc = ModelViewController()
vc.delegate = self //委托方
self.presentViewController(vc, animated: true, completion: nil)
// self.navigationController?.pushViewController(vc, animated: true)
}
func changeString(newString:String) {//实现协议的方法
print(newString)
}