(lldb) 从 swift 中的解析检索数据时出错

Question

我正在使用以下函数从 swift 中的解析中检索数据。但是我在行 "results.objectAtIndex(i) as NSDictionary" 中收到错误。我不知道什么错误以及为什么会出现该错误？请阅读我的代码并指导我！

  func parse_db() {
        var sto_tit = [String] ()
        var results : NSArray = NSArray()
        var par_object : NSDictionary = NSDictionary()
        var par_query = PFQuery(className: "story")
        par_query.whereKeyExists("story_title")
        par_query.findObjectsInBackgroundWithBlock({(NSArray objects, NSError error) in

           if (error != nil) {
               NSLog("error " + error.localizedDescription)
           } else {                   
               results = NSArray(array: objects)

               for i in 0...results.count {
                   println(i) //This line working

                   par_object = results.objectAtIndex(i) as NSDictionary //Error
                   sto_tit = par_object.objectForKey("story_title") as Array

               }
               NSLog("results %@", sto_tit)
           }
      })
    }

错误如下： 0 (lldb)

{
libswiftCore.dylib`swift_dynamicCastObjCClassUnconditional:
0x10adfc620:  pushq  %rbp
0x10adfc621:  movq   %rsp, %rbp
0x10adfc624:  pushq  %rbx
0x10adfc625:  pushq  %rax
0x10adfc626:  movq   %rsi, %rcx
0x10adfc629:  movq   %rdi, %rbx
0x10adfc62c:  xorl   %eax, %eax
0x10adfc62e:  testq  %rbx, %rbx
0x10adfc631:  je     0x10adfc64c               ;swift_dynamicCastObjCClassUnconditional 
+ 44
0x10adfc633:  movq   0x82756(%rip), %rsi       ; "isKindOfClass:"
0x10adfc63a:  movq   %rbx, %rdi
0x10adfc63d:  movq   %rcx, %rdx
0x10adfc640:  callq  0x10adff1ca               ; symbol stub for: objc_msgSend
0x10adfc645:  testb  %al, %al
0x10adfc647:  movq   %rbx, %rax
0x10adfc64a:  je     0x10adfc653               ; swift_dynamicCastObjCClassUnconditional + 51
0x10adfc64c:  addq   [=2=]x8, %rsp
0x10adfc650:  popq   %rbx
0x10adfc651:  popq   %rbp
0x10adfc652:  retq   
0x10adfc653:  leaq   0xcdc8(%rip), %rax        ; "Swift dynamic cast failed"
0x10adfc65a:  movq   %rax, 0x8ae57(%rip)       ; gCRAnnotations + 8
0x10adfc661:  int3   
0x10adfc662:  nopw   %cs:(%rax,%rax)

}

Answer 1

findObjectsInBackgroundWithBlock:

returns 一个 PFObjects 的 NSArray。所以当你尝试

var par_object = results.objectAtIndex(i) as NSDictionary

会失败，因为结果的第 i 个对象是 PFObject，无法通过这种方式转换为 NSDictionary。

但是你可以使用

par_object = results.objectAtIndex(i) as PFObject
sto_tit = par_object["story_title"] as [String] //Are you sure about that the "story_title" column is an array?

你的声明是错误的使用

var par_object = PFObject(className: "YOUR_CLASS_NAME")

(lldb) 从 swift 中的解析检索数据时出错

(lldb) error while retrieving datas from parse in swift

nsdictionary

parse-platform

swift

xcode6