取消存档 NSMutableDictionary o NSData 时出现错误？

Question

我正在尝试通过 wifi/蓝牙将信息字典从一台 iphone 发送到另一台 iphone，为此我实现了 CFnetwork 和 NSNetservice Concept。我在接收器端收到了数据。

我的代码如下......

**Sender Side**

 samDict=[NSMutableDictionary dictionary];
     [samDict setObject:@"Muhammed Musthafa" forKey:@"PP"];
     [samDict setObject:@"John P" forKey:@"Jose"];
     [samDict setObject:@"Lubaba" forKey:@"P"];
     [samDict setObject:@"JINI" forKey:@"KS"];
     [samDict setObject:@"Anusha" forKey:@"GS"];
     [samDict setObject:@"Athulya" forKey:@"V"];
     [samDict setObject:@"Riyas" forKey:@"MM"];
     [samDict setObject:@"Raihanath" forKey:@"MH"];
     [samDict setObject:@"Shabeer" forKey:@"poola"];
     [samDict setObject:@"Rajisha" forKey:@"Raji"];

     //NSLog(@" Dictionary values.............%@",samDict);

    NSMutableData *ArchiveData=[[NSMutableData alloc]init];    
    NSKeyedArchiver *archiver=[[NSKeyedArchiver alloc]initForWritingWithMutableData:ArchiveData];
    [archiver setOutputFormat: NSPropertyListXMLFormat_v1_0];

    [archiver encodeObject:self.samDict forKey:@"Some Key Values"];
    [archiver finishEncoding];    
    [archiver release];

    const uint8_t *buffer=(const uint8_t *)[ArchiveData bytes];
    NSInteger nWrtitten=[_outStream write:buffer maxLength:[ArchiveData legth]];
    if (!nWrtitten)
    {
        NSLog(@"Eorror writting to Stream %@ : %@", _outStream, [_outStream streamError]);
    }
    else
    {

        NSLog(@" Write %ld bytes to Stream %@",(long)nWrtitten, _outStream);
    }

接收方

 NSInteger bytesRead;
        uint8_t buffer[13000];
        NSMutableData *data=[[NSMutableData data]retain];           

        if (stream==_inStream)
        {


            bytesRead=[_inStream read:buffer maxLength:sizeof(buffer)];
            if (bytesRead==-1&& bytesRead==0)
            {
                NSLog(@"_inStream Error...................");
            }
            else
            {                                       
                [data appendBytes:buffer length:bytesRead];
                NSLog(@"Data Received has length   :%d\n\n",[data length]);

                NSLog(@"data............%@",data);

            }
        }

我在接收方获取了数据。数据为字节格式。我无法在接收器端取消存档此数据。如果我尝试将其取消存档为这样的字典格式

NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
   NSMutableDictionary* UnArchiveDictionary =[NSMutableDictionary dictionary];
    UnArchiveDictionary = [[unarchiver decodeObjectForKey:@"Some Key Values"] retain]; 
    NSLog(@"UnArchive Dictionary  %@",UnArchiveDictionary);  

，但不幸的是我无法以字典格式取消存档此数据。我收到行 NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data]; 的错误

我找到了一些将字节数据转换为字符串格式的代码，如下所示

size_t length=[data length];
                    unsigned char aBuffer[length];
                    [data getBytes:aBuffer length:length];
                    aBuffer[length - 1]=0;
                    NSString *messageString =aBuffer; 

                    NSLog (@"%s",messageString);

但我的问题是如何返回同一本词典。为什么在未归档时出现错误？

Answer 1

问题可能在于条件：

if (bytesRead==-1&& bytesRead==0)

将始终为假。一个变量不能同时有两个不同的值。您可能想要：

if (bytesRead==-1 || bytesRead==0)

因此，如果出现错误（或没有传输数据），您的代码不会注意到，而是将堆栈中的垃圾字节附加到可变数据中。

然后，带密钥的解存档器尝试将这些垃圾字节解释为存档，并注意到它不是存档，因此它抛出异常。