ios - 如何在 Swift/iOS 中解析 Json 并获取所需的值？

Question

这是我的 Json 数据。

 {  
   "products":[  

    {  
         "capacity":4,
         "image":"http:\/\/d1a3f4spazzrp4.cloudfront.net\/car-types\/mono\/mono-uberx.png",
         "display_name":"uberX",
         "product_id":"a1111c8c-c720-46c3-8534-2fcdd730040d",
         "description":"The low-cost Uber"
      },
      {  
         "capacity":6,
         "image":"http:\/\/d1a3f4spazzrp4.cloudfront.net\/car-types\/mono\/mono-uberxl2.png",
         "display_name":"uberXL",
         "product_id":"821415d8-3bd5-4e27-9604-194e4359a449",
         "description":"low-cost rides for large groups"
      },
      {  
         "capacity":4,
         "image":"http:\/\/d1a3f4spazzrp4.cloudfront.net\/car-types\/mono\/mono-black.png",
         "display_name":"UberBLACK",
         "product_id":"d4abaae7-f4d6-4152-91cc-77523e8165a4",
         "description":"The original Uber"
      },
      {  
         "capacity":6,
         "image":"http:\/\/d1a3f4spazzrp4.cloudfront.net\/car-types\/mono\/mono-suv.png",
         "display_name":"UberSUV",
         "product_id":"8920cb5e-51a4-4fa4-acdf-dd86c5e18ae0",
         "description":"Room for everyone"
      },
      {  
         "capacity":4,
         "image":"http:\/\/d1a3f4spazzrp4.cloudfront.net\/car-types\/mono\/mono-taxi.png",
         "display_name":"uberTAXI",
         "product_id":"3ab64887-4842-4c8e-9780-ccecd3a0391d",
         "description":"Taxi without the hassle"
      }
   ]
}

我希望所有值都由键表示，即容量、图像、显示名称、产品ID、描述，并保存在下面给出的列表中

    var  array_capacity = Array<Int>();
    var  array_image = Array<String>();
    var  array_display_name = Array<String>();
    var  array_product_id = Array<String>();
    var  array_description = Array<String>(); 

但是它崩溃了。我认为这是因为一些类型转换问题。

这是我的解析代码。

var responseDict: NSDictionary = NSJSONSerialization.JSONObjectWithData(responseData,options: NSJSONReadingOptions.MutableContainers, error:nil) as NSDictionary

        if(!(responseDict==nil)){

             var products: NSArray = responseDict["products"] as NSArray

                for item in products { // loop through data items
                    let obj = item as NSDictionary
                    for (key, value) in obj {


                       // print(key as String);

                        array_product_id.append(value as String);
                        array_display_name.append(value as String);
                        array_image.append(value as String);
                        array_description.append(value as String);
                        array_capacity.append(value as Int);

                }

            }


        }

日志

    libswiftCore.dylib`swift_dynamicCastObjCClassUnconditional:
0x109c55f30:  pushq  %rbp
0x109c55f31:  movq   %rsp, %rbp
0x109c55f34:  pushq  %rbx
0x109c55f35:  pushq  %rax
0x109c55f36:  movq   %rsi, %rcx
0x109c55f39:  movq   %rdi, %rbx
0x109c55f3c:  xorl   %eax, %eax
0x109c55f3e:  testq  %rbx, %rbx
0x109c55f41:  je     0x109c55f5d               ; swift_dynamicCastObjCClassUnconditional + 45
0x109c55f43:  movq   0x7858e(%rip), %rsi       ; "isKindOfClass:"
0x109c55f4a:  movq   %rbx, %rdi
0x109c55f4d:  movq   %rcx, %rdx
0x109c55f50:  callq  *0x63112(%rip)            ; (void *)0x000000010be04000: objc_msgSend
0x109c55f56:  testb  %al, %al
0x109c55f58:  movq   %rbx, %rax
0x109c55f5b:  je     0x109c55f64               ; swift_dynamicCastObjCClassUnconditional + 52
0x109c55f5d:  addq   $0x8, %rsp
0x109c55f61:  popq   %rbx
0x109c55f62:  popq   %rbp
0x109c55f63:  retq   
0x109c55f64:  leaq   0xecc7(%rip), %rax        ; "Swift dynamic cast failed"
0x109c55f6b:  movq   %rax, 0x7fbe6(%rip)       ; gCRAnnotations + 8
0x109c55f72:  int3   
0x109c55f73:  nopw   %cs:(%rax,%rax)

Answer 1

这里的问题是您正在快速迭代 NSDictionary。 NSDictionary 似乎不符合快速序列，因此您使用键值对 NSDictionary 进行迭代会崩溃。使用 NSDictionary 的 allKeys 方法并定期提取值，就像您对 Objective C 所做的那样，

if  let jsonData = jsonString?.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false){

  if let jsonObject = NSJSONSerialization.JSONObjectWithData(jsonData, options: NSJSONReadingOptions.AllowFragments, error: nil) as? [String: AnyObject]{

    if let products: AnyObject = jsonObject["products"]{

      for aProduct in products as NSArray{

        for aKey in (aProduct as NSDictionary).allKeys{

          println(aKey)

        }

      }

    }
  }

}

您做错的一件事是将字典中的值附加到，并且您正在使用动态转换将其转换为字符串或 Int。这不是正确的做法，它会再次使您的代码崩溃，您可以选择检查它是否可以使用 if let 转换为类型，然后将该值附加到您的数组。