本文來源電子發(fā)燒友社區(qū)，作者：劉建華， 帖子地址：https://bbs.elecfans.com/jishu_2308758_1_1.html


【目的】用QT實(shí)現(xiàn)一個(gè)串口助手。
因?yàn)槲业捻?xiàng)目是需要用到485接口來控制伺服電機(jī)的，所以掌握QT的串口收發(fā)是必需的。經(jīng)過幾天的學(xué)習(xí)從?Qt----Serial Port_冷月楓啊的博客-CSDN博客_qt serialport學(xué)習(xí)到了qtserialport的知識(shí)。現(xiàn)在分享如下：
1、用qtcreator新建空白項(xiàng)目：

2、在qtserial_demo.h上增加serialport
QT += core gui serialport
3、編寫mainwindow.h,內(nèi)容如下：

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = 0);
    ~MainWindow();
private:
    //Ui::MainWindow *ui;
    /* 串口對(duì)象 */
    QSerialPort *serialPort;
    /* 用作接收數(shù)據(jù) */
    QTextBrowser *textBrowser;
    /* 用作發(fā)送數(shù)據(jù) */
    QTextEdit *textEdit;
    /* 按鈕 */
    QPushButton *pushButton[2];
    /* 下拉選擇盒子 */
    QComboBox *comboBox[5];
    /* 標(biāo)簽 */
    QLabel *label[5];
    /* 垂直布局 */
    QVBoxLayout *vboxLayout;
    /* 網(wǎng)絡(luò)布局 */
    QGridLayout *gridLayout;
    /* 主布局 */
    QWidget *mainWidget;

     /* 設(shè)置功能區(qū)域 */
    QWidget *funcWidget;
     /* 布局初始化 */
     void layoutInit();
     /* 掃描系統(tǒng)可用串口 */
    void scanSerialPort();

     /* 波特率項(xiàng)初始化 */
     void baudRateItemInit();

    /* 數(shù)據(jù)位項(xiàng)初始化 */
    void dataBitsItemInit();

     /* 檢驗(yàn)位項(xiàng)初始化 */
    void parityItemInit();

     /* 停止位項(xiàng)初始化 */
    void stopBitsItemInit();

    private slots:
    void sendPushButtonClicked();
    void openSerialPortPushButtonClicked();
    void serialPortReadyRead();
};

#endif // MAINWINDOW_H

4、編寫mainwindow.cpp內(nèi)容如下：

#include "mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    /* 布局初始化 */
    layoutInit();

    /* 掃描系統(tǒng)的串口 */
    scanSerialPort();

    /* 波特率項(xiàng)初始化 */
    baudRateItemInit();

    /* 數(shù)據(jù)位項(xiàng)初始化 */
    dataBitsItemInit();

    /* 檢驗(yàn)位項(xiàng)初始化 */
    parityItemInit();

    /* 停止位項(xiàng)初始化 */
    stopBitsItemInit();

}

void MainWindow::layoutInit()
{
    /* 獲取屏幕的分辨率，Qt 官方建議使用這
    * 種方法獲取屏幕分辨率，防上多屏設(shè)備導(dǎo)致對(duì)應(yīng)不上
    * 注意，這是獲取整個(gè)桌面系統(tǒng)的分辨率
    */
    QList  list_screen = QGuiApplication::screens();
    /* 如果是 ARM 平臺(tái)，直接設(shè)置大小為屏幕的大小 */
    #if __arm__
     /* 重設(shè)大小 */
    this->resize(list_screen.at(0)->geometry().width(),
     list_screen.at(0)->geometry().height());
    #else
    /* 否則則設(shè)置主窗體大小為 800x480 */
    this->resize(800, 600);
    #endif
    /* 初始化 */
    serialPort = new QSerialPort(this);
    textBrowser = new QTextBrowser();
    textEdit = new QTextEdit();
    vboxLayout = new QVBoxLayout();
    funcWidget = new QWidget();
    mainWidget = new QWidget();
    gridLayout = new QGridLayout();
    /* QList 鏈表，字符串類型 */
    QList  list1;
    list1<<"串口號(hào):"<<"波特率:"<<"數(shù)據(jù)位:"<<"檢驗(yàn)位:"<<"停止位:";
    for (int i = 0; i < 5; i++){
        label[i] = new QLabel(list1[i]);
        /* 設(shè)置最小寬度與高度 */
        label[i]->setMinimumSize(80, 30);
        /* 自動(dòng)調(diào)整 label 的大小 */
        label[i]->setSizePolicy(
                    QSizePolicy::Expanding,
                    QSizePolicy::Expanding
                    );
         /* 將 label[i]添加至網(wǎng)格的坐標(biāo)(0, i) */
        gridLayout->addWidget(label[i], 0, i);
    }
    for (int i = 0; i < 5; i++) {
        comboBox[i] = new QComboBox();
        comboBox[i]->setMinimumSize(80, 30);
        /* 自動(dòng)調(diào)整 label 的大小 */
        comboBox[i]->setSizePolicy(
        QSizePolicy::Expanding,
        QSizePolicy::Expanding
    );
    /* 將 comboBox[i]添加至網(wǎng)格的坐標(biāo)(1, i) */
     gridLayout->addWidget(comboBox[i], 1, i);
    }
    /* QList 鏈表，字符串類型 */
    QList  list2;
    list2<<"發(fā)送"<<"打開串口";
    for (int i = 0; i < 2; i++) {
         pushButton[i] = new QPushButton(list2[i]);
         pushButton[i]->setMinimumSize(80, 30);
         /* 自動(dòng)調(diào)整 label 的大小 */
         pushButton[i]->setSizePolicy(
         QSizePolicy::Expanding,
         QSizePolicy::Expanding
        );
         /* 將 pushButton[0]添加至網(wǎng)格的坐標(biāo)(i, 5) */
        gridLayout->addWidget(pushButton[i], i, 5);
    }
    pushButton[0]->setEnabled(false);

    /* 布局 */
    vboxLayout->addWidget(textBrowser);
    vboxLayout->addWidget(textEdit);
    funcWidget->setLayout(gridLayout);
    vboxLayout->addWidget(funcWidget);
    mainWidget->setLayout(vboxLayout);
    this->setCentralWidget(mainWidget);

    /* 占位文本 */
    textBrowser->setPlaceholderText("接收到的消息");
    textEdit->setText("www.openedv.com");

    /* 信號(hào)槽連接 */
    connect(pushButton[0], SIGNAL(clicked()),
    this, SLOT(sendPushButtonClicked()));
    connect(pushButton[1], SIGNAL(clicked()),
    this, SLOT(openSerialPortPushButtonClicked()));

    connect(serialPort, SIGNAL(readyRead()),
    this, SLOT(serialPortReadyRead()));
}

void MainWindow::scanSerialPort()
 {
    /* 查找可用串口 */
    foreach (const QSerialPortInfo &info,
     QSerialPortInfo::availablePorts()) {
         comboBox[0]->addItem(info.portName());
     }
 }

void MainWindow::baudRateItemInit()
 {
 /* QList 鏈表，字符串類型 */
 QList list;
 list<<"1200"<<"2400"<<"4800"<<"9600"
 <<"19200"<<"38400"<<"57600"
 <<"115200"<<"230400"<<"460800"
 <<"921600";
 for (int i = 0; i < 11; i++) {
    comboBox[1]->addItem(list[i]);
 }
 comboBox[1]->setCurrentIndex(7);
}

void MainWindow::dataBitsItemInit()
{
 /* QList 鏈表，字符串類型 */
    QList list;
    list<<"5"<<"6"<<"7"<<"8";
     for (int i = 0; i < 4; i++) {
        comboBox[2]->addItem(list[i]);
     }
    comboBox[2]->setCurrentIndex(3);
}
void MainWindow::parityItemInit()
 {
     /* QList 鏈表，字符串類型 */
     QList list;
     list<<"None"<<"Even"<<"Odd"<<"Space"<<"Mark";
     for (int i = 0; i < 5; i++) {
        comboBox[3]->addItem(list[i]);
     }
    comboBox[3]->setCurrentIndex(0);
 }

void MainWindow::stopBitsItemInit()
 {
 /* QList 鏈表，字符串類型 */
 QList list;
 list<<"1"<<"2";
 for (int i = 0; i < 2; i++) {
 comboBox[4]->addItem(list[i]);
 }
 comboBox[4]->setCurrentIndex(0);
 }

void MainWindow::sendPushButtonClicked()
 {
 /* 獲取 textEdit 數(shù)據(jù),轉(zhuǎn)換成 utf8 格式的字節(jié)流 */
 QByteArray data = textEdit->toPlainText().toUtf8();
 serialPort->write(data);
 }

void MainWindow::openSerialPortPushButtonClicked()
 {
 if (pushButton[1]->text() == "打開串口") {
 /* 設(shè)置串口名 */
 serialPort->setPortName(comboBox[0]->currentText());
 /* 設(shè)置波特率 */
 serialPort->setBaudRate(comboBox[1]->currentText().toInt());
 /* 設(shè)置數(shù)據(jù)位數(shù) */
 switch (comboBox[2]->currentText().toInt()) {
 case 5:
 serialPort->setDataBits(QSerialPort::Data5);
 break;
 case 6:
 serialPort->setDataBits(QSerialPort::Data6);
 break;
 case 7:
 serialPort->setDataBits(QSerialPort::Data7);
 break;
 case 8:
 serialPort->setDataBits(QSerialPort::Data8);
 break;
 default: break;
 }
 /* 設(shè)置奇偶校驗(yàn) */
 switch (comboBox[3]->currentIndex()) {
 case 0:
 serialPort->setParity(QSerialPort::NoParity);
 break;
 case 1:
 serialPort->setParity(QSerialPort::EvenParity);
 break;
 case 2:
 serialPort->setParity(QSerialPort::OddParity);
 break;
 case 3:
 serialPort->setParity(QSerialPort::SpaceParity);
 break;
 case 4:
 serialPort->setParity(QSerialPort::MarkParity);
 break;
 default: break;
 }
 /* 設(shè)置停止位 */
 switch (comboBox[4]->currentText().toInt()) {
 case 1:
 serialPort->setStopBits(QSerialPort::OneStop);
 break;
 case 2:
 serialPort->setStopBits(QSerialPort::TwoStop);
 break;
 default: break;
 }
 /* 設(shè)置流控制 */
 serialPort->setFlowControl(QSerialPort::NoFlowControl);
 if (!serialPort->open(QIODevice::ReadWrite))
 QMessageBox::about(NULL, "錯(cuò)誤",
 "串口無法打開！可能串口已經(jīng)被占用！");
 else {
 for (int i = 0; i < 5; i++)
 comboBox[i]->setEnabled(false);
 pushButton[1]->setText("關(guān)閉串口");
 pushButton[0]->setEnabled(true);
 }
 } else {
 serialPort->close();
 for (int i = 0; i < 5; i++)
 comboBox[i]->setEnabled(true);
 pushButton[1]->setText("打開串口");
 pushButton[0]->setEnabled(false);
 }
}

void MainWindow::serialPortReadyRead()
 {
 /* 接收緩沖區(qū)中讀取數(shù)據(jù) */
 QByteArray buf = serialPort->readAll();
 textBrowser->insertPlainText(QString(buf));
 }


MainWindow::~MainWindow()
{

}

4、代碼帖完后編譯通過，在目錄工程的同級(jí)目錄下生成build_qtserial_demo-arm-debug文件夾。

5、將可執(zhí)行文件qtserial_demo拷到開發(fā)板

forlinx@forlinx:~/work/qtserial_demo/build-qtserial_demo-arm-Debug$ scp qtserial_demo root@192.168.3.168:/home/qtserial_demo
The authenticity of host '192.168.3.168 (192.168.3.168)' can't be established.
ECDSA key fingerprint is SHA256:WfJF3iuWeOnNl+KyM52kBLDLoRFcFhRDOm01a4NrZoA.
Are you sure you want to continue connecting (yes/no)? y
Please type 'yes' or 'no': yes
Warning: Permanently added '192.168.3.168' (ECDSA) to the list of known hosts.
root@192.168.3.168's password: 
qtserial_demo                                 100%  971KB  10.6MB/s   00:00

6、開發(fā)板上修改文件權(quán)限后執(zhí)行