ios - 添加 NSOperation 崩溃

Question

设置:在我的应用程序中，我有一个带有大量注释的 map 。这些注释以集群形式显示，其中数据是从服务器加载的。

要创建集群，请使用具有以下属性的 NSOperationQueue 查询注释数据库:

qualityOfService = NSQualityOfServiceUtility;
maxConcurrentOperationCount = 1;

要添加操作，我执行以下操作:

- (void)updateAfterServerReturns {
    [_q cancelAllOperations];

    NSBlockOperation* operation = [NSBlockOperation blockOperationWithBlock: ^{
        __weak typeof(self) weakSelf = self;
       [weakSelf myOperation]
    }];

    if(operation) {
        @autoreleasepool {
        [_q addOperation:operation];
        }
    }
}
- (void)myOperation {
   //retrieve data, then update map
   __weak typeof(self) weakSelf = self;  
  [weakSelf updateMap];
}

- (void)updateMap {
    __weak typeof(self) weakSelf = self;
    [[NSOperationQueue mainQueue] addOperationWithBlock:^{
  //update
   }];
}

问题:当用户四处移动并且服务器返回信息时，我收到以下崩溃信息 enqueued from com.apple.main-thread(Thread 1) 这会猛烈地停止一切。崩溃并不是每次都会发生，但常常足以令人无法接受。

有人有什么建议吗？谢谢!

崩溃详细信息

日志中:

2015-12-06 23:34:31.215 *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSArrayM insertObject:atIndex:]: object cannot be nil'
*** First throw call stack:
(0x184450f48 0x199003f80 0x18433a754 0x100224af8 0x100119c18 0x100119ca4 0x100119c84 0x100119cd0 0x100119c64 0x100119cd0 0x100119ca4 0x100119cd0 0x100119c64 0x100119c84 0x100223b9c 0x1003d50c0 0x185378374 0x1852cb1a0 0x1852bb3e8 0x18537a768 0x100e2dc68 0x100e3a780 0x100e31958 0x100e3c898 0x100e3c590 0x199a35470 0x199a35020)
libc++abi.dylib: terminating with uncaught exception of type NSException
(Recorded Frame) 

单步执行发生崩溃的线程，这些是一些:

libsystem_kernel.dylib`__pthread_kill:
0x19996f138 <+0>:  movz   x16, #0x148
0x19996f13c <+4>:  svc    #0x80
->  0x19996f140 <+8>:  b.lo   0x19996f158               ; <+32>
 0x19996f144 <+12>: stp    x29, x30, [sp, #-16]!
    0x19996f148 <+16>: mov    x29, sp
    0x19996f14c <+20>: bl     0x199956140               ; cerror_nocancel
    0x19996f150 <+24>: mov    sp, x29
    0x19996f154 <+28>: ldp    x29, x30, [sp], #16
    0x19996f158 <+32>: ret    

libdispatch.dylib`_dispatch_call_block_and_release:
    0x100e2dc90 <+0>:  stp    x20, x19, [sp, #-32]!
    0x100e2dc94 <+4>:  stp    x29, x30, [sp, #16]
    0x100e2dc98 <+8>:  add    x29, sp, #16
    0x100e2dc9c <+12>: mov    x19, x0
    0x100e2dca0 <+16>: ldr    x8, [x19, #16]
    0x100e2dca4 <+20>: blr    x8
->  0x100e2dca8 <+24>: mov    x0, x19
    0x100e2dcac <+28>: ldp    x29, x30, [sp, #16]
    0x100e2dcb0 <+32>: ldp    x20, x19, [sp], #32
    0x100e2dcb4 <+36>: b      0x100e59fec               ; symbol stub for: _Block_release

更多详细信息:

Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__:
    0x185378364 <+0>:  stp    x29, x30, [sp, #-16]!
    0x185378368 <+4>:  mov    x29, sp
    0x18537836c <+8>:  ldr    x8, [x0, #16]
    0x185378370 <+12>: blr    x8
->  0x185378374 <+16>: ldp    x29, x30, [sp], #16
    0x185378378 <+20>: ret  

Answer 1

首先确保在向数组插入任何对象之前初始化该数组。

例如，如果我们正在谈论 NSMutableArray，那么

NSMutableArray *arr = [[NSMutableArray alloc] init];

其次，确保没有插入 nil 值；插入之前先设定一个条件:

if(object) {
    // Insert to array
} else { 
    // Don't insert and investigate why it returns nil if needed
}

通过这样做，您很可能会摆脱崩溃。

但是，如果它仍然被重现，我建议使用异常断点对其进行调试并找到问题的具体来源，请点击此链接了解如何执行此操作: Exception Breakpoints