这很有趣。我有一个通用应用程序。 iPhone和iPad版本都共享相同的类，并且只有不同的xib文件。我经常得到报告，在更新iPad版本后，它将无法运行，只会崩溃。但是，对iPhone版本的更新工作正常。删除iPad应用程序，重新启动并重新安装将在启动时解决崩溃问题。
使用受影响的代码进行更新：
好的，所以在重新启用和查看受影响的代码行之后，以下是我认为导致问题的所有区域。
我希望应用程序第一次提出问题，而且只是第一次运行应用程序，所以在AppDelegate didFinishLaunchingWithOptions中我有：
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
if (! [defaults boolForKey:@"notFirstRun"]) {
UIAlertView *firstrun = [[UIAlertView alloc] initWithTitle:@"Sermon Preference" message:@"Do you prefer audio only, or video sermons? (This setting can be changed at any time in the Settings Page.)" delegate:self cancelButtonTitle:nil otherButtonTitles:@"Audio", @"Video", nil];
[firstrun show];
[firstrun release];
[defaults setBool:YES forKey:@"notFirstRun"];
}
然后我在AppDelegate Still：
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
if (buttonIndex == 0) {
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSString *nope = @"Audio";
[defaults setObject:nope forKey:@"videosermons"];
[defaults synchronize];
}
if (buttonIndex == 1) {
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSString *yup = @"Video";
[defaults setObject:yup forKey:@"videosermons"];
[defaults synchronize]; }
}
我希望在“设置”窗口中更改这些值，因此在“设置”类中我有：
- (void)viewDidLoad
{
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSString *currently = [defaults objectForKey:@"videosermons"];
if ([currently isEqualToString:@"Audio"]) {
segment.selectedSegmentIndex = 0;
}
if ([currently isEqualToString:@"Video"]) {
segment.selectedSegmentIndex = 1;
}
NSString *firstName = [defaults objectForKey:@"firstName"];
if (firstName == nil) {
}
else {
myTextField.text = firstName;
}
NSURL *url = [NSURL URLWithString:@"http://www.bellavenue.org/worship.html"];
self.content = [NSString stringWithContentsOfURL:url];
[super viewDidLoad];
}
崩溃日志所说的导致崩溃的行是：
if ([currently isEqualToString:@"Audio"]) {
所有这一切导致仅在iPad上发生崩溃，并且仅在更新已安装的先前版本而非新安装时才会崩溃？
UPDATE CRASH LOG：
Incident Identifier: EE5B1A62-12DB-4ED5-95CD-0C68CE1614BA
CrashReporter Key: 92fbea1d35e30ff292ba7362f93548dceedefe66
Hardware Model: iPad2,5
Process: Bell Avenue [1013]
Path: /var/mobile/Applications/CE1AE921-5767-4B3C-B223-2C098041C73E/Bell Avenue.app/Bell Avenue
Identifier: Bell Avenue
Version: ??? (???)
Code Type: ARM (Native)
Parent Process: launchd [1]
Date/Time: 2012-12-01 14:11:10.653 -0600
OS Version: iOS 6.1 (10B5105c)
Report Version: 104
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Crashed Thread: 0
Last Exception Backtrace:
0 CoreFoundation 0x3411529e 0x34053000 + 795294
1 libobjc.A.dylib 0x33f3297a 0x33f2a000 + 35194
2 CoreFoundation 0x34118e02 0x34053000 + 810498
3 CoreFoundation 0x3411752c 0x34053000 + 804140
4 CoreFoundation 0x3406ef64 0x34053000 + 114532
5 Bell Avenue 0x0008652e -[Settings viewDidLoad] (Settings.m:64)
6 UIKit 0x3396578c 0x337c5000 + 1705868
7 UIKit 0x3396d5fa 0x337c5000 + 1738234
8 UIKit 0x3399786a 0x337c5000 + 1910890
9 UIKit 0x33820ae4 0x337c5000 + 375524
10 UIKit 0x337c8f7c 0x337c5000 + 16252
11 UIKit 0x337c8a10 0x337c5000 + 14864
12 UIKit 0x337c845e 0x337c5000 + 13406
13 GraphicsServices 0x3afaf59e 0x3afa9000 + 26014
14 GraphicsServices 0x3afaf1ce 0x3afa9000 + 25038
15 CoreFoundation 0x340ea16e 0x34053000 + 618862
16 CoreFoundation 0x340ea112 0x34053000 + 618770
17 CoreFoundation 0x340e8f94 0x34053000 + 614292
18 CoreFoundation 0x3405beb8 0x34053000 + 36536
19 CoreFoundation 0x3405bd44 0x34053000 + 36164
20 UIKit 0x3381f7c8 0x337c5000 + 370632
21 UIKit 0x3381c644 0x337c5000 + 357956
22 Bell Avenue 0x000832fe main (main.m:13)
23 libdyld.dylib 0x39d7ab1c 0x39d79000 + 6940
Thread 0 name: Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0 libsystem_kernel.dylib 0x385b6350 0x385a5000 + 70480
1 libsystem_c.dylib 0x3a64d11e 0x3a61e000 + 192798
2 libsystem_c.dylib 0x3a68996e 0x3a61e000 + 440686
3 libc++abi.dylib 0x33e1cd4a 0x33e19000 + 15690
4 libc++abi.dylib 0x33e19ff4 0x33e19000 + 4084
5 libobjc.A.dylib 0x33f32a74 0x33f2a000 + 35444
6 libc++abi.dylib 0x33e1a078 0x33e19000 + 4216
7 libc++abi.dylib 0x33e1a110 0x33e19000 + 4368
8 libc++abi.dylib 0x33e1b594 0x33e19000 + 9620
9 libobjc.A.dylib 0x33f329cc 0x33f2a000 + 35276
10 CoreFoundation 0x3405bf1c 0x34053000 + 36636
11 CoreFoundation 0x3405bd44 0x34053000 + 36164
12 UIKit 0x3381f7c8 0x337c5000 + 370632
13 UIKit 0x3381c644 0x337c5000 + 357956
14 Bell Avenue 0x000832fe main (main.m:13)
15 libdyld.dylib 0x39d7ab1c 0x39d79000 + 6940
Thread 1:
0 libsystem_kernel.dylib 0x385b6d98 0x385a5000 + 73112
1 libsystem_c.dylib 0x3a624cf6 0x3a61e000 + 27894
2 libsystem_c.dylib 0x3a624a12 0x3a61e000 + 27154
3 libsystem_c.dylib 0x3a6248a0 0x3a61e000 + 26784
Thread 2 name: Dispatch queue: com.apple.libdispatch-manager
Thread 2:
0 libsystem_kernel.dylib 0x385a6648 0x385a5000 + 5704
1 libdispatch.dylib 0x3aee2974 0x3aeda000 + 35188
2 libdispatch.dylib 0x3aee2654 0x3aeda000 + 34388
Thread 3:
0 libsystem_kernel.dylib 0x385b6d98 0x385a5000 + 73112
1 libsystem_c.dylib 0x3a624cf6 0x3a61e000 + 27894
2 libsystem_c.dylib 0x3a624a12 0x3a61e000 + 27154
3 libsystem_c.dylib 0x3a6248a0 0x3a61e000 + 26784
Thread 4 name: WebThread
Thread 4:
0 libsystem_kernel.dylib 0x385b60fc 0x385a5000 + 69884
1 libsystem_c.dylib 0x3a61f124 0x3a61e000 + 4388
2 WebCore 0x38db41c0 0x38da8000 + 49600
3 WebCore 0x38db40f2 0x38da8000 + 49394
4 CoreFoundation 0x340ea6ca 0x34053000 + 620234
5 CoreFoundation 0x340e89bc 0x34053000 + 612796
6 CoreFoundation 0x340e8de8 0x34053000 + 613864
7 CoreFoundation 0x3405beb8 0x34053000 + 36536
8 CoreFoundation 0x3405bd44 0x34053000 + 36164
9 WebCore 0x38db22a8 0x38da8000 + 41640
10 libsystem_c.dylib 0x3a62f30e 0x3a61e000 + 70414
11 libsystem_c.dylib 0x3a62f1d4 0x3a61e000 + 70100
答案 0 :(得分：0)
系统导致应用程序中止（SIGABRT）。代码中有几个问题：
viewDidLoad中的所有代码都应该在viewWillAppear:中实际执行。当iOS加载视图时，没有任何代码与执行相关。self.content = [NSString stringWithContentsOfURL:url]是一个同步调用，阻塞主线程需要多长时间。您应该异步调用它或使用NSOperationQueue加载内容，然后再次在主线程上设置它。现在这会阻止视图控制器的加载过程，这是一个更糟糕的想法。currently对象不属于NSString类型，并且出现unrecognized selector sent to instance错误。您可能希望阅读本系列有关如何阅读和使用崩溃报告的信息：http://www.raywenderlich.com/10209/my-app-crashed-now-what-part-1