将控制台NSLog以文件形式存储到磁盘

- (void)removelogFiles{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
    NSString *rtcLogDirectory=[[paths objectAtIndex:0] stringByAppendingString:@“/NS_Log"];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    BOOL  rtcLogfileExists = [fileManager fileExistsAtPath:rtcLogDirectory];
    if (rtcLogfileExists){
        NSArray *subPathArr = [[NSFileManager defaultManager] subpathsAtPath:rtcLogDirectory];
        if (subPathArr){
            for (NSString *subPath in subPathArr){
                NSString *filePath = [rtcLogDirectory stringByAppendingPathComponent:subPath];
                [[NSFileManager defaultManager] removeItemAtPath:filePath error:nil];
            }
        }
    }
}

// 保存日志文件
- (void)redirectNSLogToDocumentFolder{
    // 如果已经连接Xcode调试则不输出到文件
    if(isatty(STDOUT_FILENO))  //STDOUT_FILENO == 1
    {
        return;
    }
    UIDevice *device = [UIDevice currentDevice];
    if([[device model] hasSuffix:@"Simulator"])
    {
        //在模拟器不保存到文件中return;
    }
    // 获取Document目录下的Log文件夹，若没有则新建
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *logDirectory = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"Log"];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    BOOL fileExists = [fileManager fileExistsAtPath:logDirectory];
    //remove logs first
    if (fileExists){
        NSArray *subPathArr = [[NSFileManager defaultManager] subpathsAtPath:logDirectory];
        if (subPathArr){
            for (NSString *subPath in subPathArr){
                NSString *filePath = [logDirectory stringByAppendingPathComponent:subPath];
                [[NSFileManager defaultManager] removeItemAtPath:filePath error:nil];
            }
        }
    }
    if (!fileExists)
    {
        [fileManager createDirectoryAtPath:logDirectory  withIntermediateDirectories:YES attributes:nil error:nil];
    }
    //
    
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"zh_CN"]];
    [formatter setDateFormat:@"yyyy-MM-dd"];
    //每次启动后都保存一个新的日志文件中
    NSString *dateStr = [formatter stringFromDate:[NSDate date]];
    NSString *logFilePath = [logDirectory stringByAppendingFormat:@"/%@.txt",dateStr];
    // freopen 重定向输出输出流，将log输入到文件
    freopen([logFilePath cStringUsingEncoding:NSASCIIStringEncoding], "a+", stdout);
    freopen([logFilePath cStringUsingEncoding:NSASCIIStringEncoding], "a+", stderr);
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.
    [self removelogFiles];
    [self redirectNSLogToDocumentFolder];
    return YES;
}