虽然大家都不愿意看到程序崩溃，但可能崩溃是每个应用必须面对的现实，既然崩溃已经发生，无法阻挡了，那我们就让它崩也崩得淡定点吧。
IOS SDK中提供了一个现成的函数 NSSetUncaughtExceptionHandler 用来做异常处理，但功能非常有限，而引起崩溃的大多数原因如：内存访问错误，重复释放等错误就无能为力了，因为这种错误它抛出的是Signal，所以必须要专门做Signal处理。首先定义一个UncaughtExceptionHandler类，代码如下：
#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
@interface UncaughtExceptionHandler : NSObject
{
BOOL dismissed;
}
+(void) InstallUncaughtExceptionHandler;
@end
//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，</span>
void UncaughtExceptionHandlers (NSException *exception);
#import "UncaughtExceptionHandler.h"
#include <libkern/OSAtomic.h>
#include <execinfo.h>
NSString * const UncaughtExceptionHandlerSignalExceptionName = @"UncaughtExceptionHandlerSignalExceptionName";
NSString * const UncaughtExceptionHandlerSignalKey = @"UncaughtExceptionHandlerSignalKey";
NSString * const UncaughtExceptionHandlerAddressesKey = @"UncaughtExceptionHandlerAddressesKey";
volatile int32_t UncaughtExceptionCount = 0;
const int32_t UncaughtExceptionMaximum = 10;
const NSInteger UncaughtExceptionHandlerSkipAddressCount = 4;
const NSInteger UncaughtExceptionHandlerReportAddressCount = 5;
NSString* getAppInfo()
{
NSString *appInfo = [NSString stringWithFormat:@"App : %@ %@(%@)\nDevice : %@\nOS Version : %@ %@\n",
[[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleDisplayName"],
[[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleShortVersionString"],
[[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleVersion"],
[UIDevice currentDevice].model,
[UIDevice currentDevice].systemName,
[UIDevice currentDevice].systemVersion];
// [UIDevice currentDevice].uniqueIdentifier];
NSLog(@"Crash!!!! %@", appInfo);
return appInfo;
}
void MySignalHandler(int signal)
{
int32_t exceptionCount = OSAtomicIncrement32(&UncaughtExceptionCount);
if (exceptionCount > UncaughtExceptionMaximum)
{
return;
}
if(signal==11)
{//比较坑爹的是 我遇到的一个问题只有iPhone5出现问题 但是我这边测试的没有iPhone5 无法直接log 可能是内存不足 果然 删除几个应用就可以了 所以加了这句
UIAlertView * tip2 = [[UIAlertView alloc]initWithTitle:@"可能原因:key" message:@"内存不足" delegate:nil cancelButtonTitle:@"ok" otherButtonTitles:nil];
[tip2 show];
[tip2 release];
}
NSMutableDictionary *userInfo = [NSMutableDictionary dictionaryWithObject:[NSNumber numberWithInt:signal] forKey:UncaughtExceptionHandlerSignalKey];
NSArray *callStack = [UncaughtExceptionHandler backtrace];
[userInfo setObject:callStack forKey:UncaughtExceptionHandlerAddressesKey];
[[[[UncaughtExceptionHandler alloc] init] autorelease]
performSelectorOnMainThread:@selector(handleException:)
withObject:
[NSException
exceptionWithName:UncaughtExceptionHandlerSignalExceptionName
reason:
[NSString stringWithFormat:
NSLocalizedString(@"Signal %d was raised.\n"
@"%@", nil),
signal, getAppInfo()]
userInfo:
[NSDictionary
dictionaryWithObject:[NSNumber numberWithInt:signal]
forKey:UncaughtExceptionHandlerSignalKey]]
waitUntilDone:YES];
}
@implementation UncaughtExceptionHandler
+(void) InstallUncaughtExceptionHandler
{
signal(SIGABRT, MySignalHandler);
signal(SIGILL, MySignalHandler);
signal(SIGSEGV, MySignalHandler);
signal(SIGFPE, MySignalHandler);
signal(SIGBUS, MySignalHandler);
signal(SIGPIPE, MySignalHandler);
}
+ (NSArray *)backtrace
{
void* callstack[128];
int frames = backtrace(callstack, 128);
char **strs = backtrace_symbols(callstack, frames);
int i;
NSMutableArray *backtrace = [NSMutableArray arrayWithCapacity:frames];
for (
i = UncaughtExceptionHandlerSkipAddressCount;
i < UncaughtExceptionHandlerSkipAddressCount +
UncaughtExceptionHandlerReportAddressCount;
i++)
{
[backtrace addObject:[NSString stringWithUTF8String:strs[i]]];
}
free(strs);
return backtrace;
}
- (void)alertView:(UIAlertView *)anAlertView clickedButtonAtIndex:(NSInteger)anIndex
{
if (anIndex == 0)
{
dismissed = YES;
}
}
- (void)handleException:(NSException *)exception
{
UIAlertView *alert =
[[[UIAlertView alloc]
initWithTitle:NSLocalizedString(@"Unhandled exception", nil)
message:[NSString stringWithFormat:NSLocalizedString(
@"You can try to continue but the application may be unstable.\n"
@"%@\n%@", nil),
[exception reason],
[[exception userInfo] objectForKey:UncaughtExceptionHandlerAddressesKey]]
delegate:self
cancelButtonTitle:NSLocalizedString(@"Quit", nil)
otherButtonTitles:NSLocalizedString(@"Continue", nil), nil]
autorelease];
[alert show];
CFRunLoopRef runLoop = CFRunLoopGetCurrent();
CFArrayRef allModes = CFRunLoopCopyAllModes(runLoop);
while (!dismissed)
{
for (NSString *mode in (NSArray *)allModes)
{
CFRunLoopRunInMode((CFStringRef)mode, 0.001, false);
}
}
CFRelease(allModes);
NSSetUncaughtExceptionHandler(NULL);
signal(SIGABRT, SIG_DFL);
signal(SIGILL, SIG_DFL);
signal(SIGSEGV, SIG_DFL);
signal(SIGFPE, SIG_DFL);
signal(SIGBUS, SIG_DFL);
signal(SIGPIPE, SIG_DFL);
if ([[exception name] isEqual:UncaughtExceptionHandlerSignalExceptionName])
{
kill(getpid(), [[[exception userInfo] objectForKey:UncaughtExceptionHandlerSignalKey] intValue]);
}
else
{
[exception raise];
}
}
void UncaughtExceptionHandlers (NSException *exception) {
NSArray *arr = [exception callStackSymbols];
NSString *reason = [exception reason];
NSString *name = [exception name];
NSString *urlStr = [NSString stringWithFormat:@"mailto://1140454645@qq.com?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]);
}
@end
然后在delegate文件里面- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions函数里面
[UncaughtExceptionHandler InstallUncaughtExceptionHandler];
NSSetUncaughtExceptionHandler (&UncaughtExceptionHandlers);