我有一个带有 qt creator 的应用程序，它可以获取地理坐标数据并将其显示在地图上。它只需要一个连接就可以正常工作，但是当涉及到不止一次连接时，它就成了一个谜。我想从具有不同地址和端口的几个 qtcp 连接中循环获取数据，然后将数据放在单独的列表中，并在读取每个连接地理数据的列表后，在不同线程中的地图上添加单独的层，每 3 秒更新一次，而所有这些层从网络数据包中同时获取数据。假设我有许多不同的 gps 接收器来收集他们的位置数据，我想将其整合到地图上。这是我的代码示例：
1.定义qtcp客户端应该连接的服务器列表：
全局变量.cpp
#define PACKET 50
struct Connects{
static QMap<QString,int> list()
{
QMap<QString,int> m;
m["sender1.com"] = 4456;
m["sender2.com"] = 4457;
m["sender3.com"] = 4458;
return m;
}
static const QMap<QString,int> myMap;
};
QMap<QString, int> const Connects::myMap = list();
2.主窗口启动地图：
主文件
void add_layer(MarbleWidget *mapWidget,MainWindow *window,Client *client,QTimer *timer ){
//get data and append to a list every 3 sec
timer = new QTimer;
QObject::connect(timer,SIGNAL(timeout()),window,SLOT(next_client()));
QObject::connect(client,SIGNAL(Client_Connected()),window,SLOT(online_slot()));
timer->start(3000);
// Add New Layer based on positions in the list
MPaintLayer* layer = new MPaintLayer(mapWidget);
for(int j = 0; j < client->data.count(); ++j){
layer->setPosition(client->data.at(j).Lat,client->data.at(j).Lon);
}
mapWidget->addLayer(layer);
}
MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent)
{
// Load Marble
MarbleWidget *mapWidget = new MarbleWidget;
mapWidget->show();
//iterate over connections address and port list
QMapIterator<QString,int> i(Connects::myMap);
while (i.hasNext()) {
i.next();
client = new Client;
client->ConnectToServer(i.key(),i.value());
//make thread pool and create new thread for adding each layer
QThreadPool pool;
QFuture<void> tr;
tr = QtConcurrent::run(&pool,add_layer,mapWidget,this,client,timer);
}
}
void MainWindow::online_slot()
{
//fetch data from the buffer and separate each entity based on size
while (client->GetLanBufferSize() >= PACKET) {
client->ReadData((char*)buffer,PACKET);
double lat,lon;
memcpy(&lat,&buffer[8],sizeof(double));
memcpy(&lon,&buffer[16],sizeof(double));
//put buffer data to target list which is defined in client
Target trg;
client->data.append(trg);
}
//remove has-readed data
for (int var = 0; var < client->data.count(); ++var) {
client->data.removeAt(var);
var--;
}
}
3.declare 类，用于根据地图上接收到的数据添加或更新新图层：
油漆层.cpp
MPaintLayer::MPaintLayer(MarbleWidget* widget)
{
S_N = QPixmap(":/mode-s.png");
}
bool MPaintLayer::render( GeoPainter *painter,ViewportParams *viewport,
const QString& renderPos, GeoSceneLayer * layer )
{
//throw a tiny png file on map based on retrieved locations
for (int var = 0; var < pos.count(); ++var) {
painter->drawPixmap(pos[var],S_N));
}
return true;
}
void MPaintLayer::setPosition(double lat,double lon)
{
pos.append(GeoDataCoordinates(lat,lon,0,GeoDataCoordinates::Degree));
}
5.定义一个接收数据格式的类：
客户端.h
class Target
{
public:
Target()
{
Lat = Lon = 0;
}
double Lat,Lon;
GeoDataCoordinates Position;
void update(double lat,double lon)
{
Lat = lat;
Lon = lon;
Position = GeoDataCoordinates(Lon,Lat,0,GeoDataCoordinates::Degree);
}
};
6.declare 建立新的 qtcp 连接和接收数据的类：
客户端.cpp
Client::Client(QObject *parent) : QObject(parent)
{
socket = new QTcpSocket(this);
connect(socket, SIGNAL(connected()),this, SLOT(on_connected()));
}
void Client::on_connected()
{
connect(socket, SIGNAL(disconnected()),this, SLOT(on_Disconnected()));
socket->setReadBufferSize(12e6);
emit Client_Connected();
}
bool Client::ReadData(char *buffer, int Leanth)
{
socket->read(buffer , Leanth);
return true;
}
int Client::GetLanBufferSize()
{
return socket->bytesAvailable();
}
void Client::on_Disconnected()
{
emit Client_DisConnected();
}
void Client::ConnectToServer(QString Address , int Port)
{
socket->connectToHost(Address, Port);
server = Address;
server_Port = Port;
}
从发送方接收到的数据格式是移动物体的位置，如下所示：
35.51243 51.22478
35.51260 51.22667
35.69270 51.03961
什么是最佳实践解决方案？因为它在地图上什么也没有显示。当我使用硬代码时，它显示了相当于每个连接的层，但读取数据流是有挑战性的。任何线索将不胜感激。