iOS 如何捕获异常？

在app启动时(didFinishLaunchingWithOptions)，添加一个异常捕获的监听。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.
    
    NSSetUncaughtExceptionHandler(&UncaughtExceptionHandler);
    InstallSignalHandler();
    return YES;
}

方式一：实现捕获异常日志并保存到本地的方法。

void UncaughtExceptionHandler(NSException *exception){
    
    // 异常日志获取
    NSArray  *excpArr = [exception callStackSymbols];
    NSString *reason = [exception reason];
    NSString *name = [exception name];
    
    NSString *excpCnt = [NSString stringWithFormat:@"exceptionType: %@ \n reason: %@ \n stackSymbols: %@",name,reason,excpArr];
    
    // 日常日志保存（可以将此功能单独提炼到一个方法中）
    NSArray  *dirArr  = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *dirPath = dirArr[0];
    NSString *logDir = [dirPath stringByAppendingString:@"/CrashLog"];
    
    BOOL isExistLogDir = YES;
    NSFileManager *fileManager = [NSFileManager defaultManager];
    if (![fileManager fileExistsAtPath:logDir]) {
        isExistLogDir = [fileManager createDirectoryAtPath:logDir withIntermediateDirectories:YES attributes:nil error:nil];
    }
    
    if (isExistLogDir) {
        // 此处可扩展
        NSString *logPath = [logDir stringByAppendingString:@"/crashLog.txt"];
        [excpCnt writeToFile:logPath atomically:YES encoding:NSUTF8StringEncoding error:nil];
    }
}

方式二：把异常崩溃信息发送至开发者邮件

void UncaughtExceptionHandler(NSException *exception) {
    /**
     *  获取异常崩溃信息
     */
    NSArray *callStack = [exception callStackSymbols];
    NSString *reason = [exception reason];
    NSString *name = [exception name];
    NSString *content = [NSString stringWithFormat:@"========异常错误报告========\nname:%@\nreason:\n%@\ncallStackSymbols:\n%@",name,reason,[callStack componentsJoinedByString:@"\n"]];
 
    /**
     *  把异常崩溃信息发送至开发者邮件
     */
    NSMutableString *mailUrl = [NSMutableString string];
    [mailUrl appendString:@"mailto:test@qq.com"];
    [mailUrl appendString:@"?subject=程序异常崩溃，请配合发送异常报告，谢谢合作！"];
    [mailUrl appendFormat:@"&body=%@", content];
    // 打开地址
    NSString *mailPath = [mailUrl stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:mailPath]];
}

获取signal信息

//2. 获取signal信息
void InstallSignalHandler(void){
   signal(SIGHUP, SignalExceptionHandler);
   signal(SIGINT, SignalExceptionHandler);
   signal(SIGQUIT, SignalExceptionHandler);
 
   signal(SIGABRT, SignalExceptionHandler);
   signal(SIGILL, SignalExceptionHandler);
   signal(SIGSEGV, SignalExceptionHandler);
   signal(SIGFPE, SignalExceptionHandler);
   signal(SIGBUS, SignalExceptionHandler);
   signal(SIGPIPE, SignalExceptionHandler);
}
void SignalExceptionHandler(int signal)
{
   NSMutableString *mstr = [[NSMutableString alloc] init];
   [mstr appendString:@"Stack:\n"];
   void* callstack[128];
   int i, frames = backtrace(callstack, 128);
   char** strs = backtrace_symbols(callstack, frames);
   for (i = 0; i <frames; ++i) {
       [mstr appendFormat:@"%s\n", strs[i]];
   }
   [SignalHandler saveCreash:mstr];
}