Realm对象已被删除或无效

Question

当我启动我的应用程序时,我执行API调用以查看是否有新数据可用.数据存储在我的本地Realm数据库中,其中一些数据显示在初始表视图控制器中.

API调用完成后,我会检查是否满足某些条件,要求我从数据库中删除一堆先前的数据,然后创建新对象.但是,当我删除旧数据时,我的应用程序崩溃时出现以下异常:

2015-08-06 11:56:32.057 MSUapp[19754:172864] *** Terminating app due to uncaught exception 'RLMException', reason: 'Object has been deleted or invalidated.'
*** First throw call stack:
(
0   CoreFoundation                      0x000000010660cc65 __exceptionPreprocess + 165
1   libobjc.A.dylib                     0x00000001083bdbb7 objc_exception_throw + 45
2   Realm                               0x0000000105b78e95 _ZL17RLMVerifyAttachedP13RLMObjectBase + 85
3   Realm                               0x0000000105b7878d _ZL10RLMGetLinkP13RLMObjectBasemP8NSString + 29
4   Realm                               0x0000000105b7c23e ___ZL17RLMAccessorGetterP11RLMProperty15RLMAccessorCodeP8NSString_block_invoke_12 + 46
5   MSUapp                              0x0000000105764867 _TFFC6MSUapp29FavoriteLeaguesViewController18generateLeagueListFS0_FT_T_U_FTCS_6LeagueS1__Sb + 39
6   MSUapp                              0x00000001057648eb _TTRXFo_oC6MSUapp6LeagueoS0__dSb_XFo_iS0_iS0__dSb_ + 27
7   libswiftCore.dylib                  0x0000000108674ae2 _TFSs14_insertionSortUSs21MutableCollectionType_USs13GeneratorType__Ss22BidirectionalIndexType_Ss18_SignedIntegerType_Ss33_BuiltinIntegerLiteralConvertible____FTRQ_GVSs5RangeQQ_5Index_RFTQQQ_9Generator7ElementS7__Sb_T_ + 1570
8   libswiftCore.dylib                  0x0000000108676682 _TFSs14_introSortImplUSs21MutableCollectionType_USs13GeneratorType__Ss21RandomAccessIndexType_Ss18_SignedIntegerType_Ss33_BuiltinIntegerLiteralConvertible_Ss16SignedNumberType_S3_____FTRQ_GVSs5RangeQQ_5Index_RFTQQQ_9Generator7ElementS8__SbSi_T_ + 1250
9   libswiftCore.dylib                  0x0000000108676172 _TFSs10_introSortUSs21MutableCollectionType_USs13GeneratorType__Ss21RandomAccessIndexType_Ss18_SignedIntegerType_Ss33_BuiltinIntegerLiteralConvertible_Ss16SignedNumberType_S3_____FTRQ_GVSs5RangeQQ_5Index_FTQQQ_9Generator7ElementS8__Sb_T_ + 1058
10  libswiftCore.dylib                  0x00000001085ec947 _TFSs4sortUSs21MutableCollectionType_USs13GeneratorType__Ss21RandomAccessIndexType_Ss18_SignedIntegerType_Ss33_BuiltinIntegerLiteralConvertible_Ss16SignedNumberType_S3_____FTRQ_FTQQQ_9Generator7ElementS6__Sb_T_ + 471
11  libswiftCore.dylib                  0x00000001086a8d9e _TPA__TFFSa4sortU__FRGSaQ__FFTQ_Q__SbT_U_FRGVSs26UnsafeMutableBufferPointerQ__T_ + 222
12  libswiftCore.dylib                  0x00000001086a8e18 _TPA__TTRG0_R_XFo_lGVSs26UnsafeMutableBufferPointerq___dT__XFo_lGS_q___iT__42 + 56
13  libswiftCore.dylib                  0x00000001085f7fda _TFSa30withUnsafeMutableBufferPointerU__fRGSaQ__U__FFRGVSs26UnsafeMutableBufferPointerQd___Q_Q_ + 522
14  libswiftCore.dylib                  0x00000001085f7db4 _TFSa4sortU__fRGSaQ__FFTQ_Q__SbT_ + 132
15  MSUapp                              0x0000000105761709 _TFC6MSUapp29FavoriteLeaguesViewController18generateLeagueListfS0_FT_T_ + 1097
16  MSUapp                              0x000000010576354b _TFC6MSUapp29FavoriteLeaguesViewController27numberOfSectionsInTableViewfS0_FCSo11UITableViewSi + 59
17  MSUapp                              0x00000001057635fa _TToFC6MSUapp29FavoriteLeaguesViewController27numberOfSectionsInTableViewfS0_FCSo11UITableViewSi + 58
18  UIKit                               0x000000010737cac3 -[UITableViewRowData _updateNumSections] + 84
19  UIKit                               0x000000010737d4b4 -[UITableViewRowData invalidateAllSections] + 69
20  UIKit                               0x00000001071c873b -[UITableView _updateRowData] + 217
21  UIKit                               0x00000001071de2b7 -[UITableView noteNumberOfRowsChanged] + 112
22  UIKit                               0x00000001071dd9f5 -[UITableView reloadData] + 1355
23  MSUapp                              0x00000001057647c6 _TFFC6MSUapp29FavoriteLeaguesViewController11viewDidLoadFS0_FT_T_U_FTO10RealmSwift12NotificationCS1_5Realm_T_ + 166
24  RealmSwift                          0x0000000105f37210 _TFF10RealmSwift41rlmNotificationBlockFromNotificationBlockFFT12notificationOS_12Notification5realmCS_5Realm_T_bTSSCSo8RLMRealm_T_U_FTSSS2__T_ + 224
25  RealmSwift                          0x0000000105f372af _TTRXFo_oSSoCSo8RLMRealm_dT__XFdCb_dCSo8NSStringdS__dT__ + 111
26  Realm                               0x0000000105c0645a -[RLMRealm sendNotifications:] + 986
27  Realm                               0x0000000105c068e6 -[RLMRealm commitWriteTransaction] + 262
28  Realm                               0x0000000105c06a48 -[RLMRealm transactionWithBlock:] + 120
29  RealmSwift                          0x0000000105f34250 _TFC10RealmSwift5Realm5writefS0_FFT_T_T_ + 176
30  MSUapp                              0x00000001056d46db _TZFC6MSUapp14DatabaseHelper23removeForSportAndSeasonfMS0_FTCS_5Sport6seasonSS_T_ + 603
31  MSUapp                              0x0000000105710d22 _TFFFC6MSUapp11AppDelegate14loadRemoteDataFS0_FT_T_U_FGSaCS_5Sport_T_U_FGSaCS_6League_T_ + 866
32  MSUapp                              0x0000000105710dc7 _TTRXFo_oGSaC6MSUapp6League__dT__XFo_iGSaS0___iT__ + 23
33  MSUapp                              0x00000001057103d1 _TPA__TTRXFo_oGSaC6MSUapp6League__dT__XFo_iGSaS0___iT__ + 81
34  MSUapp                              0x000000010575de90 _TTRXFo_iGSaC6MSUapp6League__iT__XFo_oGSaS0___dT__ + 32
35  MSUapp                              0x000000010575ddeb _TFZFC6MSUapp9APIHelper11loadLeaguesFMS0_FTSi18shouldWriteToRealmSb10completionGSqFGSaCS_6League_T___T_U_FCSo6NSDataT_ + 2763
36  MSUapp                              0x00000001056f4a0e _TTSf2n_n_n_n_n_d_i_n_n_n___TFFC6MSUapp14JSONDataSource18loadRemoteJsonDataFS0_FTSSCS_19GETParameterBuilderFCSo6NSDataT__T_U_FTCSo12NSURLRequestGSqCSo17NSHTTPURLResponse_GSqS2__GSqCSo7NSError__T_ + 2302
37  MSUapp                              0x00000001056f2d59 _TPA__TTSf2n_n_n_n_n_d_i_n_n_n___TFFC6MSUapp14JSONDataSource18loadRemoteJsonDataFS0_FTSSCS_19GETParameterBuilderFCSo6NSDataT__T_U_FTCSo12NSURLRequestGSqCSo17NSHTTPURLResponse_GSqS2__GSqCSo7NSError__T_ + 249
38  Alamofire                           0x00000001059e7599 _TTRXFo_oCSo12NSURLRequestoGSqCSo17NSHTTPURLResponse_oGSqCSo6NSData_oGSqCSo7NSError__dT__XFo_oS_oGSqS0__iGSqS1__oGSqS2___dT__ + 25
39  Alamofire                           0x00000001059e7461 _TFFFC9Alamofire7Request8responseFDS0_US_18ResponseSerializer___FT5queueGSqCSo8NSObject_18responseSerializerQ_17completionHandlerFTCSo12NSURLRequestGSqCSo17NSHTTPURLResponse_GSqQ0__GSqCSo7NSError__T__DS0_U_FT_T_U_FT_T_ + 737
40  Alamofire                           0x00000001059e690e _TPA__TFFFC9Alamofire7Request8responseFDS0_US_18ResponseSerializer___FT5queueGSqCSo8NSObject_18responseSerializerQ_17completionHandlerFTCSo12NSURLRequestGSqCSo17NSHTTPURLResponse_GSqQ0__GSqCSo7NSError__T__DS0_U_FT_T_U_FT_T_ + 206
41  Alamofire                           0x00000001059a89d7 _TTRXFo__dT__XFdCb__dT__ + 39
42  libdispatch.dylib                   0x000000010938b186 _dispatch_call_block_and_release + 12
43  libdispatch.dylib                   0x00000001093aa614 _dispatch_client_callout + 8
44  libdispatch.dylib                   0x0000000109392a1c _dispatch_main_queue_callback_4CF + 1664
45  CoreFoundation                      0x00000001065741f9 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 9
46  CoreFoundation                      0x0000000106535dcb __CFRunLoopRun + 2043
47  CoreFoundation                      0x0000000106535366 CFRunLoopRunSpecific + 470
48  GraphicsServices                    0x000000010cc17a3e GSEventRunModal + 161
49  UIKit                               0x00000001070f08c0 UIApplicationMain + 1282
50  MSUapp                              0x000000010570f857 main + 135
51  libdyld.dylib                       0x00000001093df145 start + 1
52  ???                                 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

这个调用堆栈让我假设,这是因为我在FavoriteLeaguesViewController generateLeagueList方法中的写访问权限.以下是它的正文:

var favorites = FavoritesHelper.sharedInstance.favoriteLeagues
favorites.sort { $0.sport < $1.sport }

for favorite in favorites {
  // Add to array, which we can later use for cellForRowAtIndexPath
}

favorites是类型[League],其中League是一个领域对象.我假设发生异常是因为我正在访问League对象的属性,这些属性同时已从Realm数据库中删除(因为已经在AppDelegate中启动的API调用现已完成).

我的问题是:我怎样才能防止这种情况发生？League在删除任何对象之前,如何确保不再对任何对象进行写入/读取访问？

Answer 1

您可以通过调用来检查对象是否已从Realm中删除object.invalidated- 如果它返回true,则它已被删除或Realm已手动无效.

Answer 2

我有一个非常好的方法来捕获Swift中的RLMException.

目前Swift没有显示RLMException发生的位置.

在Realm/RLMUtil.mm:266中,有RLMException的定义.

如果更改代码以生成快速错误,

Xcode现在可以显示异常发生的位置.

现在它是Swift的一部分.

// Realm/RLMUtil.mm:266
static NSException *RLMException(NSString *reason, NSDictionary *additionalUserInfo) {
    // add some code to generate a swift error. E.g. division-by-zero.
    int a = 0;
    if (reason == nil) {
        a = 1;
    }
    NSLog(@"calculating 1 / %d = %f", a, 1 / a);

    ... remainder of the original code...
}

Answer 3

我只是将断点放在方法中:

// Realm/RLMUtil.mm:193
static NSException *RLMException(NSString *reason, NSDictionary *additionalUserInfo) {
    // ...
}

在左侧面板上,您可以检查堆栈跟踪,在这里您可以找到错误抛出的位置.

Answer 4

问题出在我的FavoritesHelper班上.它有favoriteLeagueIDs和favoriteLeagues财产.我总是设置它们并使用ID作为内部使用,而其他属性用于我想要来自这些联盟的一些数据.

这意味着,所有喜欢的联赛都经常被favoriteLeagues属性(类型[League])引用,因此当我想在它们失效后获取它们时会崩溃应用程序.

我为解决这个问题所做的是将属性更改favoriteLeagues为计算属性,如下所示:

var favoriteLeagues: [League] {
    get {
        var leagues = [League]()
        for id in favoriteLeagueIDs {
            if let league = realm.objectForPrimaryKey(League.self, key: id) {
                leagues.append(league)
            }
        }
        return leagues
    }
}

现在联盟不再被引用,只需在我需要阅读时从数据库加载.由于if let语句(在这种情况下Realm.objectForPrimaryKey(:key:)方法返回)nil,因此无法加载无效或已删除的对象.

Answer 5

我无法像其他人建议的那样在 Realm 框架本身中放置断点，而是在我的整个项目中放置了一个异常断点：

这使我能够在抛出异常时捕获正确的堆栈跟踪，并找到我的错误。

Answer 6

你可以打电话 isInvalidated或invalidated判断对象无效(是)或不是(否).你也可以编写一个自定义方法来定义什么是真实的invalidate

找文件,我们会看到一个属性:

 /**
 Indicates if the object can no longer be accessed because it is now invalid.

 An object can no longer be accessed if the object has been deleted from the Realm that manages it, or
 if `invalidate` is called on that Realm.
 */
@property (nonatomic, readonly, getter = isInvalidated) BOOL invalidated;

这invalidated 是只读但是isInvalidated意味着什么？

它等于 - (BOOL)invalidated { return invalidated; }

这意味着您可以编写一个自定义方法来定义invalidate您想要的实际内容.

Answer 7

尝试在领域上创建元素而不是添加

所以：

try! realm.write {
        realm.add(...)
    }

用。。。来代替：

try! realm.write {
        realm.create(...)
    }

然后在删除操作后领域应该按预期工作！