4、Qt Project之串口数据传输

串口数据传输：

Step1：串口数据的发送和接收过程，我们需要单独的添加串口的相关模块进去，模块名称叫做serialport，我们需要建立的工程是QMainWindow的基类程序，不是QWidget程序

我们添加的位置是在xxx.pro文件当中，改文件如前所述，是包含当前工程所需要的核心模块的文件：

QT += core gui serialport

这里添加了core、gui、serialprot三个核心需要使用到的模块。

Step2：完成整个串口通讯程序的UI界面的设计工作：

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>MainWindow</class>
 <widget class="QMainWindow" name="MainWindow">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>473</width>
    <height>382</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>MainWindow</string>
  </property>
  <widget class="QWidget" name="centralWidget">
   <widget class="QLabel" name="label_6">
    <property name="geometry">
     <rect>
      <x>0</x>
      <y>0</y>
      <width>321</width>
      <height>51</height>
     </rect>
    </property>
    <property name="font">
     <font>
      <pointsize>28</pointsize>
      <italic>true</italic>
      <underline>false</underline>
      <strikeout>false</strikeout>
     </font>
    </property>
    <property name="cursor">
     <cursorShape>BlankCursor</cursorShape>
    </property>
    <property name="text">
     <string>Qt interface Demo!</string>
    </property>
    <property name="alignment">
     <set>Qt::AlignCenter</set>
    </property>
   </widget>
   <widget class="QLabel" name="label_5">
    <property name="geometry">
     <rect>
      <x>0</x>
      <y>50</y>
      <width>171</width>
      <height>51</height>
     </rect>
    </property>
    <property name="font">
     <font>
      <pointsize>16</pointsize>
      <italic>true</italic>
      <underline>false</underline>
      <strikeout>false</strikeout>
     </font>
    </property>
    <property name="cursor">
     <cursorShape>BlankCursor</cursorShape>
    </property>
    <property name="text">
     <string>SerialPort Control</string>
    </property>
    <property name="alignment">
     <set>Qt::AlignCenter</set>
    </property>
   </widget>
   <widget class="QLabel" name="label_4">
    <property name="geometry">
     <rect>
      <x>10</x>
      <y>100</y>
      <width>171</width>
      <height>21</height>
     </rect>
    </property>
    <property name="font">
     <font>
      <pointsize>10</pointsize>
      <italic>true</italic>
      <underline>false</underline>
      <strikeout>false</strikeout>
     </font>
    </property>
    <property name="cursor">
     <cursorShape>BlankCursor</cursorShape>
    </property>
    <property name="text">
     <string>Designed by : mm1994uestc</string>
    </property>
    <property name="alignment">
     <set>Qt::AlignCenter</set>
    </property>
   </widget>
   <widget class="QLabel" name="label">
    <property name="geometry">
     <rect>
      <x>10</x>
      <y>210</y>
      <width>91</width>
      <height>17</height>
     </rect>
    </property>
    <property name="text">
     <string>Send Content</string>
    </property>
   </widget>
   <widget class="QLabel" name="label_2">
    <property name="geometry">
     <rect>
      <x>0</x>
      <y>250</y>
      <width>111</width>
      <height>17</height>
     </rect>
    </property>
    <property name="text">
     <string>Recieve Content</string>
    </property>
   </widget>
   <widget class="QTextEdit" name="Send_Text">
    <property name="geometry">
     <rect>
      <x>120</x>
      <y>200</y>
      <width>231</width>
      <height>31</height>
     </rect>
    </property>
   </widget>
   <widget class="QTextEdit" name="Recieve_Text">
    <property name="geometry">
     <rect>
      <x>120</x>
      <y>240</y>
      <width>231</width>
      <height>81</height>
     </rect>
    </property>
   </widget>
   <widget class="QPushButton" name="Send">
    <property name="geometry">
     <rect>
      <x>360</x>
      <y>200</y>
      <width>98</width>
      <height>27</height>
     </rect>
    </property>
    <property name="text">
     <string>SEND</string>
    </property>
   </widget>
   <widget class="QPushButton" name="Clear">
    <property name="geometry">
     <rect>
      <x>360</x>
      <y>260</y>
      <width>98</width>
      <height>27</height>
     </rect>
    </property>
    <property name="text">
     <string>CLEAR</string>
    </property>
   </widget>
   <widget class="QComboBox" name="BaudRate">
    <property name="geometry">
     <rect>
      <x>280</x>
      <y>80</y>
      <width>78</width>
      <height>27</height>
     </rect>
    </property>
    <item>
     <property name="text">
      <string>115200</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>57600</string>
     </prop
19:41:19 收到数据：erty>
    </item>
    <item>
     <property name="text">
      <string>38400</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>19200</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>9600</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>4800</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>2400</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>1200</string>
     </property>
    </item>
   </widget>
   <widget class="QLabel" name="label_3">
    <property name="geometry">
     <rect>
      <x>290</x>
      <y>60</y>
      <width>61</width>
      <height>17</height>
     </rect>
    </property>
    <property name="text">
     <string>Baud Set</string>
    </property>
   </widget>
   <widget class="QLabel" name="label_7">
    <property name="geometry">
     <rect>
      <x>200</x>
      <y>60</y>
      <width>65</width>
      <height>17</height>
     </rect>
    </property>
    <property name="text">
     <string>Port Set</string>
    </property>
   </widget>
   <widget class="QComboBox" name="Port_Set">
    <property name="geometry">
     <rect>
      <x>190</x>
      <y>80</y>
      <width>78</width>
      <height>27</height>
     </rect>
    </property>
   </widget>
   <widget class="QComboBox" name="DataBit">
    <property name="geometry">
     <rect>
      <x>380</x>
      <y>80</y>
      <width>78</width>
      <height>27</height>
     </rect>
    </property>
    <item>
     <property name="text">
      <string>8</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>7</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>6</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>5</string>
     </property>
    </item>
   </widget>
   <widget class="QLabel" name="label_8">
    <property name="geometry">
     <rect>
      <x>390</x>
      <y>60</y>
      <width>61</width>
      <height>17</height>
     </rect>
    </property>
    <property name="text">
     <string>Data Bit</string>
    </property>
   </widget>
   <widget class="QComboBox" name="CheckBit">
    <property name="geometry">
     <rect>
      <x>190</x>
      <y>150</y>
      <width>78</width>
      <height>27</height>
     </rect>
    </property>
    <item>
     <property name="text">
      <string>None</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>Even</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>Odd</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>Mark</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>Space</string>
     </property>
    </item>
   </widget>
   <widget class="QLabel" name="label_9">
    <property name="geometry">
     <rect>
      <x>190</x>
      <y>130</y>
      <width>81</width>
      <height>20</height>
     </rect>
    </property>
    <property name="text">
     <string>Data Parity</string>
    </property>
   </widget>
   <widget class="QComboBox" name="StopBit">
    <property name="geometry">
     <rect>
      <x>280</x>
      <y>150</y>
      <width>78</width>
      <height>27</height>
     </rect>
    </property>
    <item>
     <property name="text">
      <string>1</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>1.5</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>2</string>
     </property>
    </item>
   </widget>
   <widget class="QLabel" name="label_10">
    <property name="geometry">
     <rect>
      <x>290</x>
      <y>130</y>
      <width>61</width>
      <height>17</height>
     </rect>
    </property>
    <property name="text">
     <string>Stop Bit</string>
    </property>
   </widget>
   <widget class="QComboBox" name="Stream">
    <property name="geometry">
     <rect>
      <x>380</x>
      <y>150</y>
      <width>78</width>
      <height>27</height>
     </rect>
    </property>
    <item>
     <property name="text">
      <string>NoFlowCtl</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>SoftWareCtl</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>HardWareCtl</string>
     </property>
    </item>
   </widget>
   <widget class="QLabel" name="label_11">
    <property name="geometry">
     <rect>
      <x>370</x>
      <y>130</y>
      <width>121</width>
      <height>17</height>
     </rect>
    </property>
    <property name="text">
     <string>Stream Control</string>
    </property>
   </widget>
   <widget class="QPushButton" name="Start_Stop_Button">
    <property name="geometry">
     <rect>
      <x>20</x>
      <y>130</y>
      <width>71</width>
      <height>71</height>
     </rect>
    </property>
    <property name="text">
     <string>Start/Stop</string>
    </property>
   </widget>
  </widget>
  <widget class="QMenuBar" name="menuBar">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>473</width>
     <height>25</height>
    </rect>
   </property>
  </widget>
  <widget class="QToolBar" name="mainToolBar">
   <attribute name="toolBarArea">
    <enum>TopToolBarArea</enum>
   </attribute>
   <attribute name="toolBarBreak">
    <bool>false</bool>
   </attribute>
  </widget>
  <widget class="QStatusBar" name="statusBar"/>
 </widget>
 <layoutdefault spacing="6" margin="11"/>
 <resources/>
 <connections/>
</ui>

整个界面的大致情况如下所示：

这里，我们已经看到了程序读取到的串口好：ttyUSB0这个串口

Step3：根据上面完成的界面，我们需要在mainwindow.cpp文件中实现每一个按键的触发信号和槽函数的实现，并使用connect函数见他们连接起来

void MainWindow::Read_Data()

void MainWindow::Read_Data()
{
    QByteArray buf;
    buf = PortParam.readAll();
    if(!buf.isEmpty())
    {
        QString str = this->ui->Recieve_Text->toPlainText();
        str += tr(buf);
        this->ui->Recieve_Text->clear();
        this->ui->Recieve_Text->append(str);
    }
    buf.clear();
}

void MainWindow::on_Start_Stop_Button_clicked(bool checked) //on_Port_Set_currentIndexChanged

void MainWindow::on_Start_Stop_Button_clicked(bool checked) //on_Port_Set_currentIndexChanged
{
    if(Start_Stop)
    {
        foreach (const QSerialPortInfo &info, QSerialPortInfo::availablePorts()) {
            qDebug() << "Name :" << info.portName();
            qDebug() << "Discription :" << info.description();
            qDebug() << "Manufacturer :" << info.manufacturer();
        }
        QString Port_Select = this->ui->Port_Set->currentText();
        int Port_BaudRate = this->ui->BaudRate->currentIndex();
        int Data_Bit = this->ui->DataBit->currentIndex();
        int Check_Bit = this->ui->CheckBit->currentIndex();
        int Stop_Bit = this->ui->StopBit->currentIndex();
        int Stream_Contrl = this->ui->Stream->currentIndex();

        QSerialPort::BaudRate baudrate;
        switch (Port_BaudRate) {
        case 0: baudrate = QSerialPort::Baud115200; break;
        case 1: baudrate = QSerialPort::Baud57600; break;
        case 2: baudrate = QSerialPort::Baud38400; break;
        case 3: baudrate = QSerialPort::Baud19200; break;
        case 4: baudrate = QSerialPort::Baud9600; break;
        case 5: baudrate = QSerialPort::Baud4800; break;
        case 6: baudrate = QSerialPort::Baud2400; break;
        case 7: baudrate = QSerialPort::Baud1200; break;
        default: break;
        }

        QSerialPort::DataBits databit;
        switch(Data_Bit){
        case 0: databit = QSerialPort::Data5; break;
        case 1: databit = QSerialPort::Data6; break;
        case 2: databit = QSerialPort::Data7; break;
        case 3: databit = QSerialPort::Data8; break;
        default: break;
        }

        QSerialPort::FlowControl flowcontrol;
        switch(Stream_Contrl){
        case 0: flowcontrol = QSerialPort::NoFlowControl; break;
        case 1: flowcontrol = QSerialPort::SoftwareControl; break;
        case 2: flowcontrol = QSerialPort::HardwareControl; break;
        default : break;
        }

        QSerialPort::StopBits stopbit;
        switch(Stop_Bit){
        case 0: stopbit = QSerialPort::OneStop; break;
        case 1: stopbit = QSerialPort::TwoStop; break;
        case 2: stopbit = QSerialPort::OneAndHalfStop; break;
        default: break;
        }

        QSerialPort::Parity checkbit;
        switch(Check_Bit){
        case 0: checkbit = QSerialPort::NoParity; break;
        case 1: checkbit = QSerialPort::EvenParity; break;
        case 2: checkbit = QSerialPort::OddParity; break;
        case 3: checkbit = QSerialPort::MarkParity; break;
        case 4: checkbit = QSerialPort::SpaceParity; break;
        default: break;
        }

        qDebug() << "BaudRate:" << Port_BaudRate;
        qDebug() << "Data Bit:" << Data_Bit;
        qDebug() << "Stop Bit:" << Stop_Bit;
        qDebug() << "FlowControl:" << Stream_Contrl;
        qDebug() << "Data Parity:" << Check_Bit;

        foreach (const QSerialPortInfo &info, QSerialPortInfo::availablePorts()) {
            if(info.portName() == Port_Select)
            {
                PortParam.setPort(info); //Set Serial Port
                PortParam.setPortName(Port_Select);
                if(PortParam.open(QIODevice::ReadWrite))
                {
                    PortParam.setBaudRate(baudrate); //Set Serial Port BaudRate
                    PortParam.setDataBits(databit); // Set Port Data Bit
                    PortParam.setFlowControl(flowcontrol);
                    PortParam.setStopBits(stopbit);
                    PortParam.setParity(checkbit);

                    QObject::connect(&PortParam,&QSerialPort::readyRead,this,&MainWindow::Read_Data);

                    PortParam.clearError();
                    PortParam.clear();

                    qDebug() << "Port Opened!";
                }else
                {
                    qDebug() << "No port Opened!";
                }
            }
        }
    }else
    {
        PortParam.close();
        qDebug() << "Port Closed!";
    }
    Start_Stop = !Start_Stop;
}

void MainWindow::on_Send_clicked(bool checked)

void MainWindow::on_Send_clicked(bool checked)
{
    QString T;
    QByteArray Temp;
    char *Data;
    int len,i;
    len = this->ui->Send_Text->toPlainText().size();
    T = this->ui->Send_Text->toPlainText();
    Temp = T.toLatin1();
    Data = Temp.data();

    qDebug() << len;
    qDebug() << T;
    for(i=0;i<len;i++)
    {
        qDebug() << Data[i];
    }
    qDebug() << Data[0] << Data[1] << Data[2];
    PortParam.write(Data);
}

void MainWindow::on_Clear_clicked(bool checked)

void MainWindow::on_Clear_clicked(bool checked)
{
    this->ui->Recieve_Text->clear();
}

Step4：下面使用connect函数将他们和信号连接起来：

connect(this->ui->Start_Stop_Button,SIGNAL(clicked(bool)),this,SLOT(on_Start_Stop_Button_clicked(bool checked)));
connect(this->ui->Send,SIGNAL(clicked(bool)),this,SLOT(on_Send_clicked(bool checked)));
connect(this->ui->Clear,SIGNAL(clicked(bool)),this,SLOT(on_Clear_clicked(bool)));

注1：以上步骤基本完成了Qt的Serialport的相关设计，但是我们发现在打开串口的过程当中总是存在这串口打不开的情况，这里我们在电脑的USB口上插入的是PL2303的串口芯片检查并解决如下：

从上图可以看出，我们的确找到了需要的ttyUSB0设备，但是/dev/ttyUSB0的文件对象的权限是普通用户不可以执行不可读写的状态，我们需要对它进行修改，修改之后就能顺利的使用我们的串口芯片了。

注2：关于如何在Ubuntu下如何安装Serialport模块，可以参看我的这篇博客：http://www.cnblogs.com/uestc-mm/p/8920525.html