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

环境：

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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：

QT完整示例程序地址：

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

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

目录结构如下：

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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

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#-------------------------------------------------
#
# Project created by QtCreator
#
#-------------------------------------------------

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = CommQT
TEMPLATE = app


SOURCES += main.cpp\
        mainwindow.cpp

HEADERS  += mainwindow.h

FORMS    += 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.cpp

win32 {
    SOURCES += $$PWD/CSerialPort/src/SerialPortWinBase.cpp
    SOURCES += $$PWD/CSerialPort/src/SerialPortInfoWinBase.cpp
}

unix {
    SOURCES += $$PWD/CSerialPort/src/SerialPortUnixBase.cpp
    SOURCES += $$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

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#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 itas109

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow,public CSerialPortListener // add by itas109
{
    Q_OBJECT

public:
    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);

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  // add by itas109
  p_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;

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  // add by itas109
  m_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);

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      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：

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First avaiable Port: COM1
open COM1 success
itas109

linux下结果：

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

linux下可能遇到权限问题

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

临时解决：

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$ sudo chmod 777 /dev/ttyUSB0

永久解决(dev为当前用户名)：

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

License

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

Reference: