利用 NSSetUncaughtExceptionHandler，当程序异常退出的时候，可以先进行处理，然后做一些自定义的动作，比如下面一段代码，就是网上有人写的，直接在发生异常时给某人发送邮件，
void UncaughtExceptionHandler(NSException *exception) {
NSArray *arr = [exception callStackSymbols];
NSString *reason = [exception reason];
NSString *name = [exception name];
NSString *urlStr = [NSString stringWithFormat:@"mailto://[email protected]?subject=bug报告&body=感谢您的配合!<br><br><br>"
"错误详情:<br>%@<br>--------------------------<br>%@<br>---------------------<br>%@",
name,reason,[arr componentsJoinedByString:@"<br>"]];
NSURL *url = [NSURL URLWithString:[urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
[[UIApplication sharedApplication] openURL:url];
//或者直接用代码，输入这个崩溃信息，以便在console中进一步分析错误原因
NSLog(@"1heqin, CRASH: %@", exception);
NSLog(@"heqin, Stack Trace: %@", [exception callStackSymbols]);
}然后在delegate文件里面- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions函数里面添加NSSetUncaughtExceptionHandler (&UncaughtExceptionHandler);
如果不使用上面的处理方式，崩溃时会直接显示下面内容：
2013-07-16 18:46:05.962 GONONO[12638:c07] *** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArrayI objectAtIndex:]: index 4 beyond bounds [0 .. 2]'
*** First throw call stack:
(0x1c91012 0x10cee7e 0x1c46b44 0x2f69 0x10e2705 0x162c0 0x16258 0xd7021 0xd757f 0xd66e8 0x45cef 0x45f02 0x23d4a 0x15698 0x1becdf9 0x1becad0 0x1c06bf5 0x1c06962 0x1c37bb6 0x1c36f44 0x1c36e1b 0x1beb7e3 0x1beb668 0x12ffc 0x25fd 0x2525)
libc++abi.dylib: terminate called throwing an exception
2013-07-16 18:46:05.958 GONONO[12638:c07] will crash now
2013-07-16 18:46:05.960 GONONO[12638:c07] 1heqin, CRASH: *** -[__NSArrayI objectAtIndex:]: index 4 beyond bounds [0 .. 2]
2013-07-16 18:46:05.962 GONONO[12638:c07] heqin, Stack Trace: (
0 CoreFoundation 0x01c9102e __exceptionPreprocess + 206
1 libobjc.A.dylib 0x010cee7e objc_exception_throw + 44
2 CoreFoundation 0x01c46b44 -[__NSArrayI objectAtIndex:] + 196
3 GONONO 0x00002f69 -[ViewController btnClicked:] + 185
4 libobjc.A.dylib 0x010e2705 -[NSObject performSelector:withObject:withObject:] + 77
5 UIKit 0x000162c0 -[UIApplication sendAction:to:from:forEvent:] + 96
6 UIKit 0x00016258 -[UIApplication sendAction:toTarget:fromSender:forEvent:] + 61
7 UIKit 0x000d7021 -[UIControl sendAction:to:forEvent:] + 66
8 UIKit 0x000d757f -[UIControl(Internal) _sendActionsForEvents:withEvent:] + 578
9 UIKit 0x000d66e8 -[UIControl touchesEnded:withEvent:] + 546
10 UIKit 0x00045cef -[UIWindow _sendTouchesForEvent:] + 846
11 UIKit 0x00045f02 -[UIWindow sendEvent:] + 273
12 UIKit 0x00023d4a -[UIApplication sendEvent:] + 436
13 UIKit 0x00015698 _UIApplicationHandleEvent + 9874
14 GraphicsServices 0x01becdf9 _PurpleEventCallback + 339
15 GraphicsServices 0x01becad0 PurpleEventCallback + 46
16 CoreFoundation 0x01c06bf5 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 53
17 CoreFoundation 0x01c06962 __CFRunLoopDoSource1 + 146
18 CoreFoundation 0x01c37bb6 __CFRunLoopRun + 2118
19 CoreFoundation 0x01c36f44 CFRunLoopRunSpecific + 276
20 CoreFoundation 0x01c36e1b CFRunLoopRunInMode + 123
21 GraphicsServices 0x01beb7e3 GSEventRunModal + 88
22 GraphicsServices 0x01beb668 GSEventRun + 104
23 UIKit 0x00012ffc UIApplicationMain + 1211
24 GONONO 0x000025fd main + 141
25 GONONO 0x00002525 start + 53
)
2013-07-16 18:46:05.962 GONONO[12638:c07] *** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArrayI objectAtIndex:]: index 4 beyond bounds [0 .. 2]'
*** First throw call stack:
(0x1c91012 0x10cee7e 0x1c46b44 0x2f69 0x10e2705 0x162c0 0x16258 0xd7021 0xd757f 0xd66e8 0x45cef 0x45f02 0x23d4a 0x15698 0x1becdf9 0x1becad0 0x1c06bf5 0x1c06962 0x1c37bb6 0x1c36f44 0x1c36e1b 0x1beb7e3 0x1beb668 0x12ffc 0x25fd 0x2525)
libc++abi.dylib: terminate called throwing an exception