小编Sj.*_*Sj.的帖子

MyApp在98%的情况下运行良好,但有时它会显示崩溃.它如此随机.

崩溃报告显示以下内容.

Thread : Crashed: com.apple.main-thread
0  libobjc.A.dylib                0x3b1ae626 objc_msgSend + 5
1  Foundation                     0x310e2381 _netServiceMonitorCallBack + 104
2  CFNetwork                      0x302ea3b5 _QueryRecordReply(_DNSServiceRef_t*, unsigned int, unsigned int, int, char const*, unsigned short, unsigned short, unsigned short, void const*, unsigned int, void*) + 324
3  libsystem_dnssd.dylib          0x3b7289d9 handle_query_response + 168
4  libsystem_dnssd.dylib          0x3b72773f DNSServiceProcessResult + 582
5  CFNetwork                      0x302ea3e5 _SocketCallBack_Mon(__CFSocket*, unsigned long, __CFData const*, void const*, void*) + 20
6  CoreFoundation                 0x30691189 __CFSocketPerformV0 + 580
7  CoreFoundation                 0x3068efaf __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 14
8 …

我在生产应用程序中遇到了一些奇怪的coredata错误，并且能够掌握崩溃报告。

有时会崩溃并显示以下消息

***对象0x17e400000的错误：释放未分配的指针

***对象0x17fd03730的错误：未分配指针

这是堆栈跟踪

Crashed: SQLQueue 0x13ff15250 for datastore.sqlite
SIGABRT ABORT 0x0000000183986014

0 libsystem_kernel.dylib    __pthread_kill + 8
1   libsystem_pthread.dylib  pthread_kill + 112
2   libsystem_c.dylib   abort + 140
3   libsystem_malloc.dylib  _nano_vet_and_size_of_live + 330
4   libsystem_malloc.dylib  nano_free + 220
5   libsqlite3.dylib    sqlite3_finalize + 244
6   CoreData    -[NSSQLiteConnection _finalizeStatement] + 100
7   CoreData    -[NSSQLiteConnection releaseSQLStatement] + 52
8   CoreData    newFetchedRowsForFetchPlan_MT + 2420
9   CoreData    _executeFetchRequest + 72
10  CoreData    -[NSSQLFetchRequestContext executeRequestUsingConnection:] + 60
11  CoreData    __52-[NSSQLDefaultConnectionManager handleStoreRequest:]_block_invoke + 260
12  libdispatch.dylib   _dispatch_client_callout …

我们可以NSLayoutConstraint在self.navigationcontroller.navigationbar里面添加一个视图和一个视图self.view.这里self是一个UIViewController实例,_textField是一个子视图self.view

我需要的是UI看起来应该是相似的,无论是否navigationBar是半透明.

我尝试了以下内容.但它不起作用.

NSLayoutConstraint* cn = [NSLayoutConstraint constraintWithItem:_textField
                                                      attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual
                                                         toItem:self.navigationController.navigationBar attribute:NSLayoutAttributeBottom
                                                     multiplier:1.0 constant:20];
[self.navigationcontroller.view addConstraint:cn];

这是Xcode中的错误消息:在检查/Path/image@2x.png pngcrush捕获的alpha时libpng error: Not enough image dCommand /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/copypng emitted errors but did not return a nonzero exit code to indicate failure

但即使出现此错误,应用程序也正常运行.甚至图像也在运行iOS 6.0的iPhone 4上加载

我尝试删除图像并再次添加.还尝试将其保存到预览中的png中.