Swift block传值

1.如果我们使用Swift语言进行传值…例如:填写文本框内容进行反向传值展示出来
(1)创建TableVC继承UITableViewController
(2)创建一个要跳转到的视图OneViewController继承与 UIViewController
下面我们要在AppDelegate 写一个导航!!!记住写的是TableVC导航可不是ViewController 如果写错不出现导航

let vc = TableVC()
        let nac=UINavigationController(rootViewController:vc)
        self.window?.rootViewController=nac

=========
在TableVC中
首先创建一个空分区

  var sectionName:[String]=[]
    
    var rowName1:[String]=[]
    var rowName2:[String]=[]
    var rowName3:[String]=[]
    var rowName4:[String]=[]
    
    
    
    var cellNum:Int=0

写导航内容.左边按钮.给分区内容.创建view在表格页眉

override func viewDidLoad() {
        super.viewDidLoad()
         //导航文字
        self.navigationItem. =\"我是世界上最帅的男人\"
        //给分区写内容
        sectionName=[\"小王\",\"小张\",\"小李\",\"小马\"]
        self.tableView.delegate=self;
        self.tableView.dataSource=self;
        //创建视图 将视图写在表格页眉
        self.tableView.tableFooterView=UIView()
        //左边按钮
        self.navigationItem.leftBarButtonItem=UIBarButtonItem( : \"全部\", style: .plain, target: self, action: #selector(whole))
        
        
    }
    //点击左边按钮
    @objc func whole(){
        if rowName1.count>0{
          print(\"小明：\\(rowName1[0]),\\(rowName1[1]),\\(rowName1[2])\")
        }
        if rowName2.count>0{
            print(\"小红：\\(rowName2[0]),\\(rowName2[1]),\\(rowName2[2])\")
        }
        if rowName3.count>0{
            print(\"张三：\\(rowName3[0]),\\(rowName3[1]),\\(rowName3[2])\")
        }
        if rowName4.count>0{
            print(\"李四：\\(rowName4[0]),\\(rowName4[1]),\\(rowName4[2])\")
        }
        
        
    }

分区数

 override func numberOfSections(in tableView: UITableView) -> Int {
        // #warning Incomplete implementation, return the number of sections
        return sectionName.count
    }

根据分区数判断每一个分区给多少表格个数

 override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        //每一个分区的表格对应对象的个数
        switch section {
        case 0:
            return rowName1.count
        case 1:
            return rowName2.count
        case 2:
            return rowName3.count
        case 3:
            return rowName4.count
        default:
            return 0
        }
       
    }

重用机构 并给每个分区里面的表格赋值

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        var cell:UITableViewCell! = tableView.dequeueReusableCell(withIdentifier: \"cell\")
        if cell==nil{
            
            cell = UITableViewCell(style: .default, reuseIdentifier: \"cell\")
        }
        

        switch indexPath.section {
        case 0:
            cell.textLabel?.text = rowName1[indexPath.row]
        case 1:
            cell.textLabel?.text = rowName2[indexPath.row]
        case 2:
            cell.textLabel?.text = rowName3[indexPath.row]
        case 3:
            cell.textLabel?.text = rowName4[indexPath.row]
        default:
            \"\"
        }
        

        return cell
    }

页眉高度

 override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return 80
    }

在页眉中创建一个新的View,里面写按钮 .和label

override func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        //创建view
        let view=UIView( : CGRect(x: 0, y: 0, width: UIScreen.main.bounds.width, height: 50))
        //view背景颜色
        view.backgroundColor=UIColor.lightGray
        //创建button
        let btn = UIButton( : CGRect(x:UIScreen.main.bounds.width-80-10, y: 10, width: 80, height: 30))
        btn.set (\"录入分数\", for: .normal)
        btn.addTarget(self, action: #selector(buton), for: .touchUpInside)
        btn.set Color(UIColor.red, for: .normal)
        view.addSubview(btn)
        btn.tag = 100+section
        
        let label = UILabel( : CGRect(x: 10, y: 10, width: 60, height: 30))
        view.addSubview(label)
        label.text = sectionName[section]
        
        let lineView = UIView( : CGRect(x: 0, y: 49, width: UIScreen.main.bounds.width, height: 1))
        view.addSubview(lineView)
        lineView.backgroundColor = UIColor.black
        return view

        
    }
     //设置页眉高度
    override func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
        
        return 50
    }

初始化要跳转的视图 …调用OneViewController中的block==vc.jumpScore.根据按钮tag值进行传值

@objc func buton(btn:UIButton){
        print(btn.tag)
        //初始化要跳转的页面
        let vc = OneViewController()
        ///结构体
        vc.jumpScore = {
            
            (str1,str2,str3)->() in
            
            switch btn.tag {
            case 100:
                self.rowName1.removeAll()
                self.rowName1.append(\"语文：\\(str1)\")
                self.rowName1.append(\"数学：\\(str2)\")
                self.rowName1.append(\"英语：\\(str3)\")
            case 101:
                self.rowName2.removeAll()
                self.rowName2.append(\"语文：\\(str1)\")
                self.rowName2.append(\"数学：\\(str2)\")
                self.rowName2.append(\"英语：\\(str3)\")
            case 102:
                self.rowName3.removeAll()
                self.rowName3.append(\"语文：\\(str1)\")
                self.rowName3.append(\"数学：\\(str2)\")
                self.rowName3.append(\"英语：\\(str3)\")
            case 103:
                self.rowName3.removeAll()
                self.rowName3.append(\"语文：\\(str1)\")
                self.rowName3.append(\"数学：\\(str2)\")
                self.rowName3.append(\"英语：\\(str3)\")
            default:
                \"\"
            }
            self.tableView.reloadData()
            }
        self.navigationController?.pushViewController(vc, animated: true)
     
    }

OneViewcontroller视图中
创建结构体typealias blockScore = (String,String,String)->()
因为我们写的成绩是字符串
创建一个block 便于调用 var jumpScore:blockScore?

 //结构体
    typealias blockScore = (String,String,String)->()
    var jumpScore:blockScore?
    
    var tf1:UITextField!
    var tf2:UITextField!
    var tf3:UITextField!

创建文本框 和按钮

override func viewDidLoad() {
        super.viewDidLoad()
        
        // Do any additional setup after loading the view.
        
        self.navigationItem.  = \"分数录入\"
        
        view.backgroundColor = UIColor.white
        
        let lab1 = UILabel( : CGRect(x: 30, y: 200, width:60 , height: 60))
        view.addSubview(lab1)
        lab1.text = \"语文\"
        
        let lab2 = UILabel( : CGRect(x: 30, y: 200+lab1. .height+10, width:60 , height: 60))
        view.addSubview(lab2)
        lab2.text = \"数学\"
        
        let lab3 = UILabel( : CGRect(x: 30, y: 200+lab1. .height+10+lab2. .height+10, width:60 , height: 60))
        view.addSubview(lab3)
        lab3.text = \"英语\"
        
        tf1 = UITextField( : CGRect(x: 50+lab1. .width+5, y: 200, width: UIScreen.main.bounds.width-(50+lab1. .width+5)-10, height: 60))
        view.addSubview(tf1)
        tf1.placeholder = \"请输入分数\"
        tf1.borderStyle = .roundedRect
        
        tf2 = UITextField( : CGRect(x: 50+lab1. .width+5, y: 200+tf1. .height+10, width: UIScreen.main.bounds.width-(50+lab1. .width+5)-10, height: 60))
        view.addSubview(tf2)
        tf2.placeholder = \"请输入分数\"
        tf2.borderStyle = .roundedRect
        
        tf3 = UITextField( : CGRect(x: 50+lab1. .width+5, y: 200+tf1. .height+10+tf2. .height+10, width: UIScreen.main.bounds.width-(50+lab1. .width+5)-10, height: 60))
        view.addSubview(tf3)
        tf3.placeholder = \"请输入分数\"
        tf3.borderStyle = .roundedRect
        
        let btn1 = UIButton( : CGRect(x: (UIScreen.main.bounds.width-100)/2-60, y: 200+lab1. .height+10+lab2. .height+10+lab3. .height+30, width: 100, height: 80))
        view.addSubview(btn1)
        btn1.set (\"保存\", for: .normal)
        btn1.addTarget(self, action: #selector(save), for: .touchUpInside)
        btn1.set Color(UIColor.red, for: .normal)
        
        let btn2 = UIButton( : CGRect(x: (UIScreen.main.bounds.width-100)/2+60, y: 200+lab1. .height+10+lab2. .height+10+lab3. .height+30, width: 100, height: 80))
        view.addSubview(btn2)
        btn2.set (\"返回\", for: .normal)
        btn2.addTarget(self, action: #selector(back), for: .touchUpInside)
        btn2.set Color(UIColor.red, for: .normal)
    }

点击保存按钮的时候…我们将输入的值返回给block

 @objc func save() {
        //将文本内容返回给jumpScore中 便于传值
        self.jumpScore!(tf1.text!,tf2.text!,tf3.text!)
        
        self.navigationController?.popViewController(animated: true)
    }

点击返回按钮进行页面返回

 @objc func back() {
        
        self.navigationController?.popViewController(animated: true)
    }