This application is modifying the autolayout engine from a background thread, which can lead to engine corruption and weird crashes.

 1 2015-09-28 17:32:03.098 天天送[2079:1664555] This application is modifying the autolayout engine from a background thread, which can lead to engine corruption and weird crashes.  This will cause an exception in a future release.
 2  Stack:(
 3     0   CoreFoundation                      0x0000000183320f74 <redacted> + 148
 4     1   libobjc.A.dylib                     0x0000000197f13f80 objc_exception_throw + 56
 5     2   CoreFoundation                      0x0000000183320ea4 <redacted> + 0
 6     3   Foundation                          0x000000018433a5d8 <redacted> + 88
 7     4   Foundation                          0x00000001841bca1c <redacted> + 36
 8     5   UIKit                               0x0000000188871a34 <redacted> + 532
 9     6   UIKit                               0x0000000188b798e0 <redacted> + 228
10     7   UIKit                               0x0000000188870458 <redacted> + 412
11     8   天天送                           0x0000000100241fc4 -[UIViewController(Toast) hideLoading] + 84
12     9   天天送                           0x00000001001ef4c4 __51-[FudaiPayViewController wxPayWithOrderName:price:]_block_invoke + 380
13     10  libdispatch.dylib                   0x00000001006a9d70 _dispatch_call_block_and_release + 24
14     11  libdispatch.dylib                   0x00000001006a9d30 _dispatch_client_callout + 16
15     12  libdispatch.dylib                   0x00000001006b8f38 _dispatch_root_queue_drain + 2344
16     13  libdispatch.dylib                   0x00000001006b8600 _dispatch_worker_thread3 + 132
17     14  libsystem_pthread.dylib             0x0000000198921478 _pthread_wqthread + 1092
18     15  libsystem_pthread.dylib             0x0000000198921028 start_wqthread + 4
19 )

调试微信支付时,发现偶尔会有一次崩溃的问题,跟踪,发现调试模式会报这个错误,但是正常模式会直接crash,注意看红色的那行,因为代码是在http的回包block里执行的,应该就是所谓后台执行了,修改掉

        dispatch_async(dispatch_get_main_queue(), ^{
            [weakSelf hideLoading];
            });