1.閉包

可以通過定義屬性或者定義方法進行回調(diào)的操作

1??無參無返回值

typealias funcBlock = () -> ()

(1)定義屬性

var parameterBlock : funcBlock?
if parameterBlock != nil{
    parameterBlock!();
}

對應(yīng)的調(diào)用

 block.parameterBlock = {() -> () in
     print("無參無返回值")
 }

(2)定義成方法

 func testBlock(blockfunc: funcBlock!){
        if (blockfunc) != nil{
            blockfunc() 
        }
  }

對應(yīng)的調(diào)用

 block.testBlock {
      print("-------func--------")
 }

2??有參無返回值

   typealias callBackBlock = (_ index : String ) -> ()         
    
   func callBackFuncBlock(blockfunc: callBackBlock!) {
        if blockfunc != nil{
            blockfunc("I am Amy")
        }
    }

對應(yīng)的回調(diào)

  block.callBackFuncBlock { (res: String) in
         print(res);
   }
//打印結(jié)果:I am Amy

3??有參數(shù)有返回值

   typealias paramBlock = (Int) -> String           //返回值類型是字符串

    func paramFuncBlock(blockfunc: paramBlock!) {
        if blockfunc != nil{
            let retFunc = blockfunc(5)
            print("Block\(retFunc)")
            
        }
    }

對應(yīng)的回調(diào)

     block.paramFuncBlock { (res: Int) -> String in
            return "res: \(res)*50"
      }

4??返回值是一個函數(shù)指針，入?yún)镾tring

   typealias funcBlockB = (Int,Int) -> (String)->()

    func testBlockB(blockfunc: funcBlockB!) {
        if blockfunc != nil {
            let retFunc = blockfunc(9,10)
            retFunc("The Result is")
        }
    }

對應(yīng)的回調(diào)

   block.testBlockB { (a: Int, b:Int) -> (String) -> () in
         func callBackFunc(res: String) {
             print("\(res) : \(a) + \(b) = \(a+b)")
         }
         return callBackFunc
   }
//打印結(jié)果:The Result is : 9 + 10 = 19

5??返回值是一個函數(shù)指針，入?yún)镾tring 返回值也是String

    typealias funcBlockC = (Int,Int) -> (String)->String
    func testBlockC(blockfunc: funcBlockC!) {
        if (blockfunc) != nil {
            let retfunc = blockfunc(9,10)
            let str = retfunc("The Result is")
            print("\(str)")
        }
  
    }

對應(yīng)的回調(diào)

block.testBlockC { (a: Int, b: Int) -> (String) -> String in
     func sumFunc(res: String) -> String {
                let resNum = a + b
                return "\(res)  \(a) + \(b) = \(resNum)"
            }
            return sumFunc
  }
//打印結(jié)果: The Result is  9 + 10 = 19

以上??