CSerialPort教程4.3.x (4) - CSerialPort在QT中的使用

环境：

QT: 5.6.3

前言

CSerialPort项目是一个基于C/C++的轻量级开源跨平台串口类库，可以轻松实现跨平台多操作系统的串口读写，同时还支持C#, Java, Python, Node.js等。

CSerialPort项目的开源协议自 V3.0.0.171216 版本后采用GNU Lesser General Public License v3.0

为了让开发者更好的使用CSerialPort进行开发，特编写基于4.3.x版本的CSerialPort教程系列。

CSerialPort项目地址：

• https://github.com/itas109/CSerialPort
• https://gitee.com/itas109/CSerialPort

QT完整示例程序地址：

• https://github.com/itas109/CSerialPort/tree/master/examples/CommQT
• https://gitee.com/itas109/CSerialPort/tree/master/examples/CommQT

1. 新建QT项目

新建一个QT项目目,解决方案名称为CommQT

【文件】-【新建文件或项目】-【Application(Qt)】-【Qt Widgets Application】-【choose…】-【名称: CommQT】

在CommQT解决方案目录下载CSerialPort源码

$ cd CommQT
$ git clone https://github.com/itas109/CSerialPort

目录结构如下：

D:/CommQT $ tree
.
+--- CommQT.pro
+--- CSerialPort
|   +--- include
|   |   +--- CSerialPort
|   |   |   +--- SerialPort.h
|   |   |   +--- SerialPortInfo.h
|   +--- src
|   |   +--- SerialPort.cpp
|   |   +--- SerialPortBase.cpp
|   |   +--- SerialPortInfo.cpp
|   |   +--- SerialPortInfoBase.cpp
|   |   +--- SerialPortInfoUnixBase.cpp
|   |   +--- SerialPortInfoWinBase.cpp
|   |   +--- SerialPortUnixBase.cpp
|   |   +--- SerialPortWinBase.cpp
+--- main.cpp
+--- mainwindow.cpp
+--- mainwindow.h
+--- mainwindow.ui

2. CommQT.pro中增加必要的CSerialPort依赖

CommQT.pro中增加CSerialPort依赖

#-------------------------------------------------
#
# Project created by QtCreator
#
#-------------------------------------------------QT       += core guigreaterThan(QT_MAJOR_VERSION, 4): QT += widgetsTARGET = CommQT
TEMPLATE = appSOURCES += main.cpp\mainwindow.cppHEADERS  += mainwindow.hFORMS    += mainwindow.ui# add by itas109
# 1. headers
INCLUDEPATH += "$$PWD/CSerialPort/include"# 2. sources
SOURCES += $$PWD/CSerialPort/src/SerialPortBase.cpp
SOURCES += $$PWD/CSerialPort/src/SerialPort.cpp
SOURCES += $$PWD/CSerialPort/src/SerialPortInfoBase.cpp
SOURCES += $$PWD/CSerialPort/src/SerialPortInfo.cppwin32 {SOURCES += $$PWD/CSerialPort/src/SerialPortWinBase.cppSOURCES += $$PWD/CSerialPort/src/SerialPortInfoWinBase.cpp
}unix {SOURCES += $$PWD/CSerialPort/src/SerialPortUnixBase.cppSOURCES += $$PWD/CSerialPort/src/SerialPortInfoUnixBase.cpp
}# 3. add system libs
win32-msvc*:LIBS += advapi32.lib
win32-msvc*:LIBS += setupapi.lib
win32-g++:LIBS += libsetupapi# 4. define UNICODE
DEFINES += _UNICODE
# end by itas109

3. 在QT中添加CSerialPort代码

3.1 增加CSerialPort的头文件、继承类、接收函数及CSerialPort实例对象

在mainwindow.h文件中

• 增加CSerialPort的头文件
• MainWindow类继承CSerialPortListener
• 增加接收函数onReadEvent(const char *portName, unsigned int readBufferLen)
• 增加CSerialPort的实例对象
• 增加QPlainTextEdit控件接收数据

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H#include <QMainWindow>// add by itas109
#include <QPlainTextEdit>#include "CSerialPort/SerialPort.h"
#include "CSerialPort/SerialPortInfo.h"
using namespace itas109;
// end by itas109namespace Ui {
class MainWindow;
}class MainWindow : public QMainWindow,public CSerialPortListener // add by itas109
{Q_OBJECTpublic:explicit MainWindow(QWidget *parent = 0);~MainWindow();private:Ui::MainWindow *ui;// add by itas109
private:void onReadEvent(const char *portName, unsigned int readBufferLen);signals:void emitUpdateReceive(QString str);private slots:void OnUpdateReceive(QString str);private:QPlainTextEdit * p_plainTextEditReceive;CSerialPort m_serialPort;// end by itas109
};#endif // MAINWINDOW_H

3.2 增加串口的相关实现代码

在mainwindow.cpp文件增加

• MainWindow::MainWindow中增加CSerialPort的测试代码
• 增加OnReceive函数的实现

#include "mainwindow.h"
#include "ui_mainwindow.h"MainWindow::MainWindow(QWidget *parent) :QMainWindow(parent),ui(new Ui::MainWindow)
{ui->setupUi(this);// add by itas109p_plainTextEditReceive = NULL;p_plainTextEditReceive = new QPlainTextEdit();this->setCentralWidget(p_plainTextEditReceive);std::vector<SerialPortInfo> portNameList = CSerialPortInfo::availablePortInfos();if (portNameList.size() > 0){p_plainTextEditReceive->moveCursor (QTextCursor::End);p_plainTextEditReceive->insertPlainText(QString("First avaiable Port: %1\n").arg(portNameList[0].portName));}else{p_plainTextEditReceive->moveCursor (QTextCursor::End);p_plainTextEditReceive->insertPlainText("No avaiable Port");return;}connect(this,&MainWindow::emitUpdateReceive,this,&MainWindow::OnUpdateReceive,Qt::QueuedConnection);m_serialPort.connectReadEvent(this);m_serialPort.init(portNameList[0].portName);m_serialPort.open();if (m_serialPort.isOpen()){p_plainTextEditReceive->moveCursor (QTextCursor::End);p_plainTextEditReceive->insertPlainText(QString("open %1 success\n").arg(portNameList[0].portName));m_serialPort.writeData("itas109", 7);}else{p_plainTextEditReceive->moveCursor (QTextCursor::End);p_plainTextEditReceive->insertPlainText(QString("open %1 failed\n").arg(portNameList[0].portName));}// end by itas109
}MainWindow::~MainWindow()
{delete ui;// add by itas109m_serialPort.disconnectReadEvent();// end by itas109
}// add by itas109
void MainWindow::onReadEvent(const char *portName, unsigned int readBufferLen)
{if(readBufferLen > 0){char data[1024];int recLen = m_serialPort.readData(data,readBufferLen > 1023 ? 1023 : readBufferLen);if (recLen > 0){data[recLen] = '\0';emitUpdateReceive(QString::fromLocal8Bit(data,recLen));}}
}void MainWindow::OnUpdateReceive(QString str)
{p_plainTextEditReceive->moveCursor (QTextCursor::End);p_plainTextEditReceive->insertPlainText(str);
}
// end by itas109

4. 结果

代码中的COM2对应的串口为RS232环回测试硬件，因此对应的结果为：
程序启动后，初始化并打开串口COM2，接收窗打印open xxx success，发送数据itas09,随后接收窗打印itas09

windows下结果：

First avaiable Port: COM1
open COM1 success
itas109

linux下结果：

First avaiable Port: /dev/ttyUSB0
open /dev/ttyUSB0 success
itas109

linux下可能遇到权限问题

open port error: Unable to open /dev/ttyUSB0: 权限不够

临时解决：

$ sudo chmod 777 /dev/ttyUSB0

永久解决(dev为当前用户名)：

$ sudo usermod -aG dialout dev
$ newgrp dialout # 立即生效

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License

License under CC BY-NC-ND 4.0: 署名-非商业使用-禁止演绎

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Reference:

1. https://github.com/itas109/CSerialPort
2. https://gitee.com/itas109/CSerialPort
3. https://blog.csdn.net/itas109