Question

QT问题：我用qDebug()输出QByteArray变量，为什么只能输出一个” ？

我在写TCP的客户端，以下代码是其中一个按键的槽
代码如下：
void tcpClient::on_RunProcessButton_clicked()
{

message=tr("run ComputeLine\r\n"); //message是QString变量

QByteArray block;

QDataStream out(&block,QIODevice::WriteOnly);

out.setVersion(QDataStream::Qt_4_8);

out<<quint16(0)<<message;

out.device()->seek(0);

out<<quint16(sizeof(block)-sizeof(quint16));

qDebug()<<block; //qDebug输出检查block数据

Client->write(block);
}

qdebug的输出结果是：“
为什么会这样？

Answer 1

The QByteArray class provides an array of bytes.QByteArray can be used to store both raw bytes (including '\0's) and traditional 8-bit '\0'-terminated strings. Using QByteArray is much more convenient than using const char *. Behind the scenes, it always ensures that the data is followed by a '\0' terminator, and uses implicit sharing (copy-on-write) to reduce memory usage and avoid needless copying of data.

这样你就可以遍历了：
QByteArray ba("Hello world");
char *data = ba.data();
while (*data) {
cout << "[" << *data << "]" << endl;
++data;
}