當IOS App發生Exception時生成自定義Log Report

昨天看到有人POST一遍程序異常退出時發送郵件報告的代碼的文章，
今天試了一次，發現很實用，
可以幫助我們Developer在沒有Debug Console的情況下建立Log Report,
可惜是BAD_EXC_ACCESS的Exception就不能捕捉到Log Report了，
不過還是有用的，所以發上來。

// Define exception handler callback function
void UncaughtExceptionHandler(NSException* exception)
{
    // Get the exception detail infomation
    NSArray* arr = [exception callStackSymbols];
    NSString* reason = [exception reason];
    NSString* name = [exception name];
    NSString* exceptionStr = [NSString stringWithFormat:@"Exception Name : %@\nReason : %@\n Call Stack Symbols :\n%@", name,reason,[arr componentsJoinedByString:@"\n"]];

    // Save to log file and file encoding was UTF-8
    [exceptionStr writeToFile:[[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, TRUE) objectAtIndex:0] stringByAppendingPathComponent:@"exception.log"] atomically:TRUE encoding:NSUTF8StringEncoding error:nil];

    // Print the exception message in debug console
    NSLog(exceptionStr);
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Setup the exception callback handler
    NSSetUncaughtExceptionHandler (&UncaughtExceptionHandler);

    return TRUE;
}