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This article mainly introduces Qt how to achieve network collection, the article introduces in great detail, has a certain reference value, interested friends must read it!

I. Preface

The last article has opened the serial port collection of one of the data sources, this time we want to talk about network acquisition, network communication is the most used three, TCP/UDP/HTTP, of which tcp communication includes two kinds of client server, tcp communication uses multiple handshake mechanism not to lose packets, but consumes a lot of resources and needs to establish a connection. Udp communication may lose packets in the case of large amount of data or unstable network, and the order cannot be guaranteed, but the data of a packet must be correct. Because it takes up very few resources and does not need to establish a connection, there are many applications in many scenarios. Since I have personally used udp, I have not found the case of packet loss. It may be because the amount of data is not large enough or in the local area network. Anyway, it is quite cool to use. Http communication is very popular at present, especially for data exchange with the server. Basically, post requests and then returns a string of json data to parse the corresponding json data. This time the use of TCP communication as an example, the other two can be expanded by themselves, but also very simple.

Second, the functions realized

Automatically load all the controls in the plug-in file to generate a list, with more than 120 controls by default.

Drag to the canvas to automatically generate the corresponding control, WYSIWYG.

On the right side of the Chinese attribute bar, change the corresponding attributes immediately applied to the corresponding selected controls, intuitive and concise, very suitable for rookies to use.

The original attribute bar text translation mapping mechanism is extremely efficient, and it is very convenient to expand the attribute bar of other languages.

The properties of all controls are automatically extracted and displayed in the right property bar, including the enumerated value drop-down box.

Support manual selection of plug-in files, external import plug-in files.

You can export all control configuration information for the current canvas to a xml file.

You can manually select the xml file to open the control layout and automatically load the control according to the xml file.

Can pull the slider, check the analog data check box, text box input, three ways to generate data to apply all controls.

The control supports eight azimuth pull adjustments, adapts to any resolution, and fine-adjusts the position up and down the keyboard.

Through the serial port acquisition, network acquisition, database collection of three ways to set data.

The code is extremely concise, the comments are very detailed, and can be used as an embryonic form of configuration to expand more functions.

Pure Qt writing, support any Qt version + any compiler + any system.

Third, effect picture

4. Core code void frmData::initServer () {/ / instantiates serial port class, binds signal slot com = new QextSerialPort (QextSerialPort::EventDriven, this); connect (com, SIGNAL (readyRead ()), this, SLOT (readDataCom (); / / instantiates network communication client class, binds signal slot tcpClient = new QTcpSocket (this); connect (tcpClient, SIGNAL (readyRead ()), this, SLOT (readDataClient () / / instantiate the network communication server class, bind signal slot tcpSocket = NULL; tcpServer = new QTcpServer (this); connect (tcpServer, SIGNAL (newConnection ()), this, SLOT (newConnection (); / / start timer to read database collection data timer = new QTimer (this); connect (timer, SIGNAL (timeout ()), this, SLOT (readDataDb (); timer- > setInterval (1000) } void frmData::on_btnOpenTcpClient_clicked () {if (ui- > btnOpenTcpClient- > text () = = "connection") {tcpClient- > connectToHost (App::TcpServerIP, App::TcpServerPort); bool ok = tcpClient- > waitForConnected (1000); if (ok) {setEnable (ui- > btnOpenTcpClient, false); ui- > btnOpenTcpClient- > setText ("disconnect");} else {tcpClient- > disconnectFromHost () SetEnable (ui- > btnOpenTcpClient, true); ui- > btnOpenTcpClient- > setText ("connection");}} void frmData::on_btnOpenTcpServer_clicked () {if (ui- > btnOpenTcpServer- > text () = = "listening") {# if (QT_VERSION > QT_VERSION_CHECK) bool ok = tcpServer- > listen (QHostAddress::AnyIPv4, App::TcpListenPort); # else bool ok = tcpServer- > listen (QHostAddress::Any, App::TcpListenPort) # endif if (ok) {setEnable (ui- > btnOpenTcpServer, false); ui- > btnOpenTcpServer- > setText ("stop");}} else {if (tcpSocket! = NULL) {tcpSocket- > disconnectFromHost ();} tcpSocket = NULL; tcpServer- > close (); setEnable (ui- > btnOpenTcpServer, true); ui- > btnOpenTcpServer- > setText ("listen") }} void frmData::readDataClient () {QByteArray data = tcpClient- > readAll (); if (data.length () txtValue- > setText (QString::number (value)); append (3, data.toHex ());} void frmData::readDataServer () {QByteArray data = tcpSocket- > readAll (); if (data.length () txtValue- > setText (QString::number (value)); append (3, data.toHex ()) } void frmData::newConnection () {while (tcpServer- > hasPendingConnections ()) {if (tcpSocket! = NULL) {tcpSocket- > disconnectFromHost ();} tcpSocket = tcpServer- > nextPendingConnection (); connect (tcpSocket, SIGNAL (readyRead ()), this, SLOT (readDataServer ());}} these are all the contents of the article "how Qt implements Network Collection". Thank you for reading! Hope to share the content to help you, more related knowledge, welcome to follow the industry information channel!

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