Ios 如何从Firebase检索嵌套数据？？应用程序正在崩溃

我的Firebase存储看起来像这样

我可以在“兴趣”下保存，但当我试图检索用户id下的所有数据时，应用程序崩溃。我是Firebase的新手，经验不足，不知道如何调用所有数据（所有信息：电子邮件、位置、姓名等以及感兴趣的孩子）

有人能帮我吗？这是我的代码：

 func fetchUser() {
    guard let uid = FIRAuth.auth()?.currentUser?.uid else {
        //for some reason uid = nil
        return
    }

    FIRDatabase.database().reference().child("users").child(uid).observeSingleEventOfType(.Value, withBlock: { (snapshot) in

        if let dictionary = snapshot.value as? [String: AnyObject] {
            //                self.navigationItem.title = dictionary["name"] as? String

            let user = User()
            user.setValuesForKeysWithDictionary(dictionary)
            self.setUpProfileInformationWithUser(user)
        }

        }, withCancelBlock: nil)
}

---

您的应用程序正在崩溃，原因是

用户。setValuesForKeysWithDictionary（dictionary）

。在类定义中，

interest

只是另一个属性，但当您从Firebase检索它时，它实际上是一个字典，因此编译器无法分别映射它。我可以很快想到两个选择

将

interest

更改为类定义中的词典

按如下所示的老方法提取数据

FIRDatabase.database().reference().child("users").child(uid).observeSingleEventOfType(.Value, withBlock: { (snapshot) in

if let dictionary = snapshot.value as? [String: AnyObject] {
    //                self.navigationItem.title = dictionary["name"] as? String

    guard let email = dictionary["email"] as! String, location = dictionary["location"] as! String, name = dictionary["name"] as! String, imageURL = dictionary["profileImageUrl"] as! String, description = dictionary["userDescription"] as! String, userName = dictionary["username"] as! String, interestDic = dictionary["interest"] as! [String : AnyObject] else
    {
        print("Error extracting FrB data")
        return
    }

    let interest = interestDic["interest"] as String

    let user = User(email, location, imageURL, description, userName, interest)

    self.setUpProfileInformationWithUser(user)
}

---

免责声明：我个人没有尝试过第一个选项，但值得一试。

你能发布你的应用程序崩溃堆栈跟踪吗？谢谢你的回复，我尝试了这两个选项好几次，但它说用户不能接受参数，所以我不确定如何修复。你能发布你得到的确切错误吗？这可能是因为您没有构造函数，因此需要为每个新创建的对象分配所有属性。当我放入代码时，出现了许多错误，但主要错误是：条件绑定的初始值设定项必须具有可选类型，而不是“[String:AnyObject]”，然后当我删除“guard”时，它带来了更多的错误。您可能想看看我刚才关于检索Firebase数据的回答。。overflow.com/a/39862631

    2016-11-20 12:50:53.999 Your Niche[34689:1654014] -[__NSDictionaryI                 length]: unrecognized selector sent to instance 0x7f8bbd00f620
    2016-11-20 12:50:54.052 Your Niche[34689:1654014] *** Terminating         app due to uncaught exception 'NSInvalidArgumentException', reason: '-        [__NSDictionaryI length]: unrecognized selector sent to instance                 0x7f8bbd00f620'
    *** First throw call stack:
    (
        0   CoreFoundation                      0x00000001055c9d85 __exceptionPreprocess + 165
1   libobjc.A.dylib                     0x0000000107b5cdeb objc_exception_throw + 48
2   CoreFoundation                      0x00000001055d2d3d -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
3   CoreFoundation                      0x0000000105518cfa ___forwarding___ + 970
4   CoreFoundation                      0x00000001055188a8 _CF_forwarding_prep_0 + 120
5   libswiftCore.dylib                  0x000000010810c0c8 _TTSf4g_d___TFSSCfT12_cocoaStringPs9AnyObject__SS + 120
6   libswiftCore.dylib                  0x00000001080cc873 _TFSSCfT12_cocoaStringPs9AnyObject__SS + 19
7   libswiftFoundation.dylib            0x0000000108485d70 _TF10Foundation24_convertNSStringToStringFGSqCSo8NSString_SS + 16
8   Your Niche                          0x0000000103fb2f8b _TToFC10Your_Niche4Users8interestGSqSS_ + 75
9   Foundation                          0x000000010615219b -[NSObject(NSKeyValueCoding) setValue:forKey:] + 288
10  Foundation                          0x000000010619399e -[NSObject(NSKeyValueCoding) setValuesForKeysWithDictionary:] + 261
11  Your Niche                          0x0000000103fbe790 _TFFC10Your_Niche21ProfileViewController9fetchUserFT_T_U_FCSo15FIRDataSnapshotT_ + 464
12  Your Niche                          0x0000000103f9fc1c _TTRXFo_oCSo15FIRDataSnapshot_dT__XFdCb_dS__dT__ + 60
13  Your Niche                          0x0000000104081431 __71-[FIRDatabaseQuery observeSingleEventOfType:withBlock:withCancelBlock:]_block_invoke + 37
14  Your Niche                          0x0000000104081731 __92-[FIRDatabaseQuery observeSingleEventOfType:andPreviousSiblingKeyWithBlock:withCancelBlock:]_block_invoke + 110
15  Your Niche                          0x00000001040a7dcf __43-[FChildEventRegistration fireEvent:queue:]_block_invoke.64 + 88
16  libdispatch.dylib                   0x00000001085fbd9d _dispatch_call_block_and_release + 12
17  libdispatch.dylib                   0x000000010861c3eb _dispatch_client_callout + 8
18  libdispatch.dylib                   0x00000001086041ef _dispatch_main_queue_callback_4CF + 1738
19  CoreFoundation                      0x00000001055230f9 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 9
20  CoreFoundation                      0x00000001054e4b99 __CFRunLoopRun + 2073
21  CoreFoundation                      0x00000001054e40f8 CFRunLoopRunSpecific + 488
22  GraphicsServices                    0x0000000109403ad2 GSEventRunModal + 161
23  UIKit                               0x00000001065a8f09 UIApplicationMain + 171
24  Your Niche                          0x0000000103f857d2 main + 114
25  libdyld.dylib                       0x000000010865092d start + 1
    )
    libc++abi.dylib: terminating with uncaught exception of type NSException
    (lldb) 

FIRDatabase.database().reference().child("users").child(uid).observeSingleEventOfType(.Value, withBlock: { (snapshot) in

if let dictionary = snapshot.value as? [String: AnyObject] {
    //                self.navigationItem.title = dictionary["name"] as? String

    guard let email = dictionary["email"] as! String, location = dictionary["location"] as! String, name = dictionary["name"] as! String, imageURL = dictionary["profileImageUrl"] as! String, description = dictionary["userDescription"] as! String, userName = dictionary["username"] as! String, interestDic = dictionary["interest"] as! [String : AnyObject] else
    {
        print("Error extracting FrB data")
        return
    }

    let interest = interestDic["interest"] as String

    let user = User(email, location, imageURL, description, userName, interest)

    self.setUpProfileInformationWithUser(user)
}