swift基础页面传值

1、页面属性传值

(一)、单纯代码跳转传值:

SecondViewController:

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let threeVC = storyboard.instantiateViewController(withIdentifier: "threeViewControllerID") as! threeViewController
 threeVC.myStr="控制器2向控制器3传值"
self.present(threeVC, animated: true, completion: nil)

threeViewController:

 var myStr=String()//全局变量
 override func viewDidLoad() {
        super.viewDidLoad()
        print("页面属性传值:\(myStr)"
  }
(二)、storyboard拉线跳转,页面参数传递:

SecondViewController:

 //拉线跳转页面传值
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        let theSegue=segue.destination as! threeViewController
        theSegue.myStr="这是通过另一种方式传值"
    }

threeViewController:与上面的相同。

2.通过userDefault存储数据:这个可以多页面间传值

UserDefaults().setValue("王珊", forKey: "userName")//存数据
UserDefaults().string(forKey: "userName") ?? ""//取数据

3.协议传值:

反向传值为例:点击返回按钮返回到上一个页面并传递参数。
threeViewController:

//(一)要创建一个协议,写在class之前
protocol FTVCdelegte : NSObjectProtocol{
    //在协议里面,声明许多方法
    // 第一个,改变标题
    func change(title:String)
    //第二个,改变背景色
    func ChangeColoer (Coloer:UIColor)
    //是否成功的标志
    func ChangSucces(YON:Bool)
}

//(二)创建一个遵守协议的对象,写在定义属性处。
 var delegate_zsj:FTVCdelegte?

//(三)点击返回,传递参数
 @IBAction func backBtnAction(_ sender: UIButton) {
        delegate_zsj?.change(title: "首页")
        delegate_zsj?.ChangeColoer(Coloer: UIColor.red)
        delegate_zsj?.ChangSucces(YON: true)
        self.navigationController?.popViewController(animated: true)
    }

SecondViewController:

//(四)继承代理:
class SecondViewController: UIViewController,FTVCdelegte,ChangeBtnDelege{...

   //(五)实现协议方法:必须全部实现
  //更改主题名字
    func change(title: String) {
        self.title = title
    }
    //更改背景色
    func ChangeColoer(Coloer: UIColor) {                 self.view.backgroundColor = Coloer
    }
    //是否成功
    func ChangSucces(YON: Bool) {
        print(YON)
    }

//(六)跳转页面时挂上代理
 @IBAction func tiaozhuanBtnAction(_ sender: Any) {
        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        let threeVC = storyboard.instantiateViewController(withIdentifier: "threeViewControllerID") as! threeViewController
        threeVC.delegate_zsj = self
        self.navigationController?.pushViewController(threeVC, animated: true)
    }

4.闭包(block)传值:

反向传值为例:点击返回按钮返回到上一个页面并传递参数。
threeViewController:

//(一)声明一个block方法:
 var bbchange:((_ title:String,_ myColor:UIColor)->Void)?

//(二)返回上一个页面并传递参数:
  @IBAction func backBtnAction(_ sender: UIButton) {
        bbchange?("文档",UIColor.green)
        self.navigationController?.popViewController(animated: true)
    }

SecondViewController:

//(三)跳到下一级页面调用block方法
 @IBAction func tiaozhuanBtnAction(_ sender: Any) {
        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        let threeVC = storyboard.instantiateViewController(withIdentifier: "threeViewControllerID") as! threeViewController
        threeVC.bbchange={
            ( title:String,myColor:UIColor) in
            self.title=title
            self.view.backgroundColor=myColor
        }
        self.navigationController?.pushViewController(threeVC, animated: true)
    }

https://www.jianshu.com/p/2b0e3e1e8fa6

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