Question

我正在尝试在Swift中创建Block。

我已经像这样创建了类和声明的块

typealias JSONParserBlock = (dict:NSDictionary?,error:NSError?) -> Void

变量声明：

var block: JSONParserBlock!

和功能：

func Getdata(WebService: String, RequsetedParameter Param:NSDictionary?, BLOCK: JSONParserBlock!) -> Void
{}

但我的问题是当我从另一个类调用此函数时，此函数不会执行

函数调用是这样的：

var objJsonParser:JsonParser?

objJsonParser?.Getdata(str as String, RequsetedParameter:Dictionary, BLOCK:
    { (dict, error) in
        print("success")
})

自定义类代码

import UIKit

class JsonParser: NSObject,NSURLConnectionDelegate
{
    typealias JSONParserBlock = (dict:NSDictionary?,error:NSError?) -> Void

    var block: JSONParserBlock!
    var Data:NSMutableData?=nil
    var delegate:JsonParserDelegate?
    var DICT:NSDictionary!
    var error: NSErrorPointer=nil
    func Getdata(WebService: String, RequsetedParameter Param:NSDictionary?, BLOCK: JSONParserBlock!) -> Void
    {
        self.block=BLOCK;
        Data = NSMutableData()
        let urlPath: String = "http://192.168.13.2/freshbakala/admin/json/GetCategory.php"
        let url: NSURL = NSURL(string: urlPath)!
        let request: NSURLRequest = NSURLRequest(URL: url)
        let connection: NSURLConnection = NSURLConnection(request: request, delegate: self, startImmediately: true)!
        connection.start()
    }

    func connection(didReceiveResponse: NSURLConnection!, didReceiveResponse response: NSURLResponse!)
    {
        self.Data = NSMutableData()
    }
    func connection(connection: NSURLConnection!, didReceiveData data: NSData!)
    {
        self.Data?.appendData(data)
    }
    func connectionDidFinishLoading(connection: NSURLConnection!)
    {
        let error:NSError
        let jsonresult:NSDictionary
        print("Response is received")
        do
        {
            jsonresult = try NSJSONSerialization.JSONObjectWithData(self.Data!, options: NSJSONReadingOptions.MutableContainers) as! NSDictionary
            print(jsonresult)
            block(dict: jsonresult,error: nil)

        }
        catch
        {

        }

    }
}

Answer 1

您需要在GetData函数中调用闭包。这样的事情应该做：

func Getdata(WebService: String, RequsetedParameter Param:NSDictionary?, BLOCK: JSONParserBlock!) -> Void
{
  let dict: NSDictionary? = nil    // set these to something meaningful
  let error: NSError? = nil
  BLOCK(dict: dict, error: error)  // call the closure
}

Answer 2

除Mrwerdo指出的问题外，另一个问题是此代码：

var objJsonParser:JsonParser?

objJsonParser?.Getdata(str as String, RequsetedParameter:Dictionary, BLOCK: {
    (dict, error) in
    print("success")
})

实际上并没有做任何事情并且不会抱怨因为objJsonParser是nil，除非你为它分配了一些东西而且调用中的?意味着GetData什么都不做因为对象是零。

在Swift中创建块不起作用

2 个答案: