覆盖prefix.pch IOS中的NSLOG

Question

我读了这篇文章:http://weakreference.wordpress.com/2011/06/22/overriding-nslog-on-ios/.

本文的想法是将这两个内容添加到应用程序的prefix.pch文件中,以便您可以覆盖NSLog的行为.

我要添加的两件事是:

#define NSLog(...) customLogger(__VA_ARGS__);

和

void customLogger(NSString *format, ...) {
    va_list argumentList;
    va_start(argumentList, format);
    NSMutableString * message = [[NSMutableString alloc] initWithFormat:format
        arguments:argumentList];

    [message appendString:@"Our Logger!"]; // Our custom Message!
    NSLogv(message, argumentList); // Originally NSLog is a wrapper around NSLogv.
    va_end(argumentList);
    [message release];
}

xCode抛出错误匹配错误,它会找到customLogger的重复项.

有没有人成功覆盖NSLog？

谢谢!

编辑以回应Rob:

好,太棒了.我们正在取得进步!我就像你问的那样动了东西.这是我们现在拥有的:

我的自定义记录器:

void customLogger(NSString *format, ...) {

    va_list args;
    va_start(args, format);
    va_end(args);
    [newLogger log:format withArgs:args];
}

//This is a newLogger Method
+ (void) log:(NSString *)format withArgs:(va_list) args{

    NSArray *occ = [format componentsSeparatedByString:@"%@"];

    NSInteger characterCount = [occ count]; 

    NSArray *stringItems = [format componentsSeparatedByString:@"%@"];

    NSMutableString *tmp = [[NSMutableString alloc] initWithFormat: @"%@",[stringItems objectAtIndex:0]];

    for( int i = 1; i < characterCount; i++ ) {
        NSString *value = va_arg(args, NSString *);
        [tmp appendString:value];
        [tmp appendString:[stringItems objectAtIndex:i]];
    }

    // Need to alter the above and actually do something with the args! 
    [tmp appendString:@"\n"];
    [[newLogger sharedInstance].logBuffer appendString:tmp];

    if ([newLogger sharedInstance].textTarget){
        [[newLogger sharedInstance].textTarget setText:sharedInstance.logBuffer];
    }
}

当我调用+ log时,我在线程1上收到SIBABRT错误.

Answer 1

听起来就像你customLogger在.pch文件中定义的那样.这意味着每个.m文件都包含它,因此.o您的项目创建的每个文件都包含它自己的副本customLogger.这就是您从链接器获得重复的符号定义错误的原因.

你需要在声明customLogger中声明.pch,如下所示:

void customLogger(NSString *format, ...);

并创建一个customLogger.m包含定义的文件.