页面传值1

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//
// ViewController.swift
// 页面传值
//
// Created by SZT on 2016/11/4.
// Copyright © 2016年 SZT. All rights reserved.
//

import UIKit

/*
界面通信：界面传值
（1）从前往后传
-- 属性传值
（2）从后往前传
-- <1>代理传值，<2>closure(闭包)传值
*/
class ViewController: UIViewController {
var label:UILabel?

override func viewDidLoad() {
    super.viewDidLoad()
    
    label = UILabel(frame: CGRectMake(50, 150, 90, 30))
    label?.text = "海贼王"
    view.addSubview(label!)
    navigationItem.title = "FirstVC"
    let btn = UIButton(frame: CGRectMake(50,200,90,40))
    btn.backgroundColor = UIColor.grayColor()
    btn.setTitle("push", forState: .Normal)
    btn.addTarget(self, action: "pushToSecondVC", forControlEvents: .TouchUpInside)
    view.addSubview(btn)
    
    
}

func pushToSecondVC(){
    
    let secondVC = SecondViewController()
    //将当前的控制器设置为secondVC的代理
    secondVC.delegate = self
    //实例化
    //传值
    secondVC.labelStr = label?.text
    navigationController?.pushViewController(secondVC, animated: true)
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

}
//设置了代理就一定要遵循协议
extension ViewController:secondProtocol{
func translateString(str: String) {
label?.text = str
}
}