怎样发送16进制的数字？

Question

NSMutableString *tosend=[[NSMutableString alloc] init];
            [tosend appendString:[NSString stringWithFormat:@"%c",0]];
            [tosend appendString:[NSString stringWithFormat:@"%c",0]];
            [tosend appendString:[NSString stringWithFormat:@"%c",0]];
            [tosend appendString:[NSString stringWithFormat:@"%c",0]];
            [tosend appendString:[NSString stringWithFormat:@"%c",0]];
            [tosend appendString:[NSString stringWithFormat:@"%c",0]];
            [tosend appendString:[NSString stringWithFormat:@"%c",0]];
            [tosend appendString:[NSString stringWithFormat:@"%c",0]];
            NSData *valData = [tosend dataUsingEncoding:NSUTF8StringEncoding];
           
             [peripheral writeValue:valData forCharacteristic:characteristic type:CBCharacteristicWriteWithResponse];这样也不行

Answer 1

先确定你是要发字符0还是二进制数据0，另外可以先试试随便发个abc之类的看看能不能正确收到

Answer 2

1、用的是 NSURLConnection 吗？
2、0x00000000 存储是就是 0.
3、peripheral 是什么？一个 Socket 封装？

Answer 3

这样可以：
        NSMutableData *data=[[NSMutableData alloc] initWithCapacity:0];
        int8_t byte0 = 0xfe;
        [data appendBytes:&byte0 length:sizeof(byte0)];
        int8_t byte1 = 0x82;
        [data appendBytes:&byte1 length:sizeof(byte1)];
        int8_t byte2 = 0x00;
        [data appendBytes:&byte2 length:sizeof(byte2)];
        int8_t byte3 = 0x00;
        [data appendBytes:&byte3 length:sizeof(byte3)];
        int8_t byte4 = 0x00;
        [data appendBytes:&byte4 length:sizeof(byte4)];
        int8_t byte5 = 0x02;
        [data appendBytes:&byte5 length:sizeof(byte5)];        NSLog(@"%@",data);//<fe820000 0002>        [_peripheral writeValue:data forCharacteristic:_characteristic type:CBCharacteristicWriteWithResponse];