iphone - 发送动态数据

我为移动定义了一个结构

typedef struct {
    MsgType msgType;
    int newFallenStonesSize;
    char *newFallenStones;
} MsgMove;

并发送如下数据：

MsgMove message;
message.msgType = MsgTypeMove;
message.newFallenStones = (char *)malloc(nrNewFallenStones*sizeof(char));
for (int i=0; i<nrNewFallenStones; i++) {
    message.newFallenStones[i]=newFallenStones[i];
}
message.newFallenStonesSize = nrNewFallenStones;

NSData *data = [NSData dataWithBytes:&message length:(2*sizeof(int)+message.newFallenStonesSize*sizeof(char))];

[[KKGameKitHelper sharedGameKitHelper] sendDataToAllPlayers:data reliable:YES];

数据在发送时是正确的，但是当我收到这样的数据时：

else if (msg->msgType == MsgTypeMove)
{
    MsgMove *msgMove = (MsgMove *) [data bytes];
    for (int i=0; i<msgMove->newFallenStonesSize; i++) {
        NSLog(@"New Stone received:%i",msgMove->newFallenStones[i]);
    }
}

值已更改。例如1、6、3，而我收到76、105 98。

有人知道为什么会这样吗？

最佳答案

主要问题是您正在通过网络发送指向数据的指针，而不是实际数据。当您为message.newFallenStones分配空间时，它将被设置为内存中与您的MsgMove结构不相邻的某些随机位置。然后，将数据写入该其他存储位置。您打包传输的是MsgMove结构（带有指向内存中其他位置的指针）以及随便出现在内存中的随机字节。

处理此问题的典型方法是将您的整个消息一起分配，并将数据写入其末尾。更像：

typedef struct {
    MsgType msgType;
    int newFallenStonesSize;
    char newFallenStones;        // The first newFallenStones value
} MsgMove;

然后发送

MsgMove *message;
message = (MsgMove *)malloc(sizeof(MsgMove)+nrNewFallenStones-1);
message->msgType = MsgTypeMove;
message->newFallenStonesSize = nrNewFallenStones;
char *newStones = &MsgMove->newFallenStones;
for (int i=0; i<nrNewFallenStones; i++) {
    newStones[i]=newFallenStones[i];
}

NSData *data = [NSData dataWithBytes:message length:(sizeof(MsgMove)+nrNewFallenStones-1)];

[[KKGameKitHelper sharedGameKitHelper] sendDataToAllPlayers:data reliable:YES];

关于iphone - 发送动态数据，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/11396627/