Swift-通过块传递结构数组并检索成员 [英] Swift - Pass struct array through block and retrieve members

问题描述

我有一个完成块，该完成块将数据的结构数组传递给另一个viewcontroller.

此数据是在viewDidLoad中接收的，例如:

  var packArray = [Any]()//该块返回Any覆盖func viewDidLoad(){super.viewDidLoad()BuildArray.buildArrayFromQuery(queryForCollection:"Pack"，发件人:self){(结果)在self.packArray = [结果]}} 

打印出此self.packArray会在一行上返回以下所有内容，而我现在不知道如何提取数据.

  [[静态ParseStarterProject_Swift.BuildArray.(buildArrayFromQuery(queryForCollection:Swift.String，发件人:__ObjC.UIViewController，completeBlock:(Any)->())->()).(collectionStruct#1)(名称:"pk00"，描述:这是一些文字"，标题:不是凶手"，图片:< PFFile:0x60000005fc80>，id:"rHITAAHJYk")，静态ParseStarterProject_Swift.BuildArray.:Swift.String，发送者:__ObjC.UIViewController，completeBlock:(任何)->())->()).(collectionStruct#1)(名称:"pk01"，描述:这是一些文字"，标题:成瘾"，图像:< PFFile:0x600000240300>，id:"uGHHpPF89e")，静态ParseStarterProject_Swift.BuildArray.(buildArrayFromQuery(queryForCollection:Swift.String，发送方:__ ObjC.UIViewController，completeBlock :(任何))->())->()).(collectionStruct#1)(名称:"pk02"，描述:这是一些文字"，标题:毛巾很吵"，图像:< PFFile:0x600000240570>，id:"PeM7hJ4sih")，静态ParseStarterProject_Swift.BuildArray.(buildArrayFromQuery(queryForCollection:Swift.String，发件人:__ObjC.UIViewController，completeBlock:(Any)->())->()).(collectionStruct#1)(名称:"pk03"，说明:"This is some text"，标题:"Class action"，图像:< PFFile:0x6000002407e0>，id:"LoSXT2PFoS")，静态ParseStarterProject_Swift.buildArray.(buildArrayFromQuery(queryForCollection:Swift.String，发件人:__ObjC.UIViewController，completeBlock:(Any)->())->()).(collectionStruct#1)(名称:"pk04"，描述:这是一些文本"，标题:啤酒"，图片:< PFFile:0x600000240a50>，id:"vxEsd13twt")，静态ParseStarterProject_Swift.BuildArray.(buildArrayFromQuery(queryForCollection:Swift.String，发送者:__ ObjC.UIViewController，completeBlock:(Any)->())->()).(collectionStruct#1)(名称:"pk05"，说明:"This is some text"，标题:"Not again ..."，图片:< PFFile:0x600000240cc0> ;, id:"JNqaAgtdRb")，静态ParseStarterProject_Swift.BuildArray.(buildArrayFromQuery(queryForCollection:Swift.String，sender:__ObjC.UIViewController，completeBlock:(Any)->())->()).(collectionStruct#1)(名称:"pk06"，描述:这是一些文字"，标题:外国汽车"，图片:< PFFile:0x600000240f30>，id:"Hb16TDXGbz")，静态ParseStarterProject_Swift.BuildArray.(buildArrayFromQuery(queryForCollection:Swift.String，发件人:__ ObjC.UIViewController，completeBlock :(任何)->())->()).(collectionStruct#1)(名称:"pk07"，描述:这是一些文字"，标题:皮肤问题"，图像:< PFFile:0x6000002411a0>，id:"MUYDMnJCrU")，静态ParseStarterProject_Swift.buildArray.(buildArrayFromQuery(queryForCollection:Swift.String，发件人:__ObjC.UIViewController，completeBlock:(Any)->())->()).(collectionStruct#1)(名称:"pk08"，描述:这是一些文本"，标题:垃圾食品"，图片:< PFFile:0x600000241410>，id:"yowAfJlcmr")，静态ParseStarterProject_Swift.BuildArray.(buildArrayFromQuery(queryForCollection:Swift.String，发送者:__ ObjC.UIViewController，completeBlock:(任何)->())->()).(collectionStruct#1)(名称:"pk09"，描述:这是一些文本"，标题:"Delusion"，图像:< PFFile:0x600000241680>，id:"TiLAKBPmaD")]] 

以前我正在使用:

  cell.labelCell.text = self.packArray [indexPath.item] .packDescription 

但是现在返回没有成员packDescription.我可能可以使用字符串处理并创建混乱，但是必须有一种更好的方法将数据作为实际数组获取.我知道我将其强制转换为Any，但找不到另一种通过完成块从struct数组中获取数据的方法.

-----编辑----

在创建数组的类中有一个struct，以及来自struct的数组结果以Any的形式通过completeBlock传递

  class func buildArrayFromQuery(queryForCollection:字符串，发件人:UIViewController，completeBlock:@转义(_结果:任意)->空白) {struct collectionStruct {var名称:字符串var说明:字符串var title:字符串var image:PFFilevar id:字符串}var collectionArray = [collectionStruct]() 

然后从PFQuery中创建它，然后将所得数组通过完成处理程序传回

  query.findObjectsInBackground(block:{(objects，error)in如果错误！= nil {打印(错误！)} if let packs = objects {用于包装物品{打印(fromName)打印(对象)让arrayName = object.object(forKey:fromName)as！细绳让arrayDescription = object.object(forKey:fromDescription)为！细绳让arrayTitle = object.object(forKey:fromTitle)为！细绳让arrayImage = object.object(forKey:fromImage)为！PF文件让arrayID = object.objectId作为String！collectionArray.append(collectionStruct(name:arrayName，description:arrayDescription，title:arrayTitle，image:arrayImage，id:arrayID！))}}completeBlock(结果:collectionArray)}) 

解决方案

您需要将查询结果转换为所需的类型.如果将packArray设为可选，则可以使用

直接分配

  var packArray:[collectionStruct]?self.packArray =结果为?[collectionStruct] 

使用该代码，如果不能将结果强制转换为正确的数组类型，则self.packArray将包含nil.

或者您可以使用可选的绑定:

  var packArray:[collectionStruct] = [] 

...

 如果structsArray =结果为[collectionStruct] {self.packArray = structsArray} 

您应该在viewDidLoad之外定义packArray:

  var packArray:[collectionStruct] = []覆盖func viewDidLoad(){super.viewDidLoad()BuildArray.buildArrayFromQuery(queryForCollection:"Pack"，发件人:自我){(造成如果structsArray =结果为[collectionStruct] {self.packArray = structsArray}} 

您的代码在viewDidLoad内部定义了一个局部变量packArray，它使事情变得混乱.我建议不要使用具有相同名称的实例变量和局部变量.

i have a completion block that hands an struct array of data to another viewcontroller.

This data is received in viewDidLoad like:

  var packArray = [Any]()// the block is returning Any

    override func viewDidLoad() {
        super.viewDidLoad()
             BuildArray.buildArrayFromQuery(queryForCollection: "Pack", sender: self) { (result) in     
                  self.packArray = [result]
             }
    }

printing this self.packArray returns the following all on one line and i now have no idea how i can extract the data.

[[static ParseStarterProject_Swift.BuildArray.(buildArrayFromQuery (queryForCollection : Swift.String, sender : __ObjC.UIViewController, completeBlock : (Any) -> ()) -> ()).(collectionStruct #1)(name: "pk00", description: "This is some text", title: "Not a murderer", image: <PFFile: 0x60000005fc80>, id: "rHITAAHJYk"), static ParseStarterProject_Swift.BuildArray.(buildArrayFromQuery (queryForCollection : Swift.String, sender : __ObjC.UIViewController, completeBlock : (Any) -> ()) -> ()).(collectionStruct #1)(name: "pk01", description: "This is some text", title: "Addiction", image: <PFFile: 0x600000240300>, id: "uGHHpPF89e"), static ParseStarterProject_Swift.BuildArray.(buildArrayFromQuery (queryForCollection : Swift.String, sender : __ObjC.UIViewController, completeBlock : (Any) -> ()) -> ()).(collectionStruct #1)(name: "pk02", description: "This is some text", title: "Towels are noisy", image: <PFFile: 0x600000240570>, id: "PeM7hJ4sih"), static ParseStarterProject_Swift.BuildArray.(buildArrayFromQuery (queryForCollection : Swift.String, sender : __ObjC.UIViewController, completeBlock : (Any) -> ()) -> ()).(collectionStruct #1)(name: "pk03", description: "This is some text", title: "Class action", image: <PFFile: 0x6000002407e0>, id: "LoSXT2PFoS"), static ParseStarterProject_Swift.BuildArray.(buildArrayFromQuery (queryForCollection : Swift.String, sender : __ObjC.UIViewController, completeBlock : (Any) -> ()) -> ()).(collectionStruct #1)(name: "pk04", description: "This is some text", title: "Beer", image: <PFFile: 0x600000240a50>, id: "vxEsd13twt"), static ParseStarterProject_Swift.BuildArray.(buildArrayFromQuery (queryForCollection : Swift.String, sender : __ObjC.UIViewController, completeBlock : (Any) -> ()) -> ()).(collectionStruct #1)(name: "pk05", description: "This is some text", title: "Not again...", image: <PFFile: 0x600000240cc0>, id: "JNqaAgtdRb"), static ParseStarterProject_Swift.BuildArray.(buildArrayFromQuery (queryForCollection : Swift.String, sender : __ObjC.UIViewController, completeBlock : (Any) -> ()) -> ()).(collectionStruct #1)(name: "pk06", description: "This is some text", title: "Foreign cars", image: <PFFile: 0x600000240f30>, id: "Hb16TDXGbz"), static ParseStarterProject_Swift.BuildArray.(buildArrayFromQuery (queryForCollection : Swift.String, sender : __ObjC.UIViewController, completeBlock : (Any) -> ()) -> ()).(collectionStruct #1)(name: "pk07", description: "This is some text", title: "Skin problems", image: <PFFile: 0x6000002411a0>, id: "MUYDMnJCrU"), static ParseStarterProject_Swift.BuildArray.(buildArrayFromQuery (queryForCollection : Swift.String, sender : __ObjC.UIViewController, completeBlock : (Any) -> ()) -> ()).(collectionStruct #1)(name: "pk08", description: "This is some text", title: "Junk food", image: <PFFile: 0x600000241410>, id: "yowAfJlcmr"), static ParseStarterProject_Swift.BuildArray.(buildArrayFromQuery (queryForCollection : Swift.String, sender : __ObjC.UIViewController, completeBlock : (Any) -> ()) -> ()).(collectionStruct #1)(name: "pk09", description: "This is some text", title: "Delusion", image: <PFFile: 0x600000241680>, id: "TiLAKBPmaD")]]

previously i was using:

cell.labelCell.text = self.packArray[indexPath.item].packDescription

but this now returns that there is no member packDescription. I probably could go and use string handling and create a mess but there must be a better way of getting the data as an actual array. i know I'm casting it as Any but couldn't figure out another way to get the data from a struct array through a completion block.

----- EDIT ----

In the class where the array is created there is a struct, and array from struct the result is passed through the completeBlock as Any

class func buildArrayFromQuery(queryForCollection: String,
       sender: UIViewController, 
       completeBlock: @escaping (_ result: Any) -> Void) {

    struct collectionStruct {
        var name : String
        var description : String
        var title : String
        var image : PFFile
        var id: String
    }

        var collectionArray = [collectionStruct]()

this is then created from a PFQuery, and the resultant array is passes back through the completion handler

query.findObjectsInBackground(block: { (objects, error) in

if error != nil {
    print(error!)

} else if let packs = objects {


    for object in packs {

        print(fromName)

        print(object)

        let arrayName = object.object(forKey: fromName) as! String
        let arrayDescription = object.object(forKey: fromDescription) as! String
        let arrayTitle = object.object(forKey: fromTitle) as! String
        let arrayImage = object.object(forKey: fromImage) as! PFFile
        let arrayID = object.objectId as String!

        collectionArray.append(collectionStruct(name: arrayName, description: arrayDescription, title: arrayTitle, image: arrayImage, id: arrayID!))
    }

}


completeBlock(result: collectionArray)

})

解决方案

You need to cast the result of the query to the desired type. If you make packArray an optional, you could assign it directly using

var packArray: [collectionStruct]?

self.packArray = result as? [collectionStruct]

With that code, if result can't be cast to the correct array type, self.packArray will contain nil.

Or you could use optional binding:

var packArray: [collectionStruct] = []

...

if structsArray = result as [collectionStruct] {
  self.packArray = structsArray
}

You should define packArray outside of viewDidLoad:

var packArray: [collectionStruct] = []

override func viewDidLoad() {
  super.viewDidLoad()
    BuildArray.buildArrayFromQuery(queryForCollection: "Pack", 
     sender: self) { 
      (result) in 
      if structsArray = result as [collectionStruct] {
        self.packArray = structsArray
     }
}

Your code defines a local variable packArray inside viewDidLoad, which confuses things. I advise against using an instance variable and a local variable with the same name.

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