78 基于QThread的多线程编程

78.1 创建项目

通过QtCreator，在C:\Users\Minwei\Projects\Qt路径下，创建名为Thread的项目。

78.2 设计界面

C:\Users\Minwei\Projects\Qt\Thread\threaddialog.ui：

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<?xml version="1.0" encoding="UTF-8"?>
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<ui version="4.0">
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 <class>ThreadDialog</class>
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 <widget class="QDialog" name="ThreadDialog">
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  <property name="geometry">
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   <rect>
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    <x>0</x>
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    <y>0</y>
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    <width>93</width>
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    <height>70</height>
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   </rect>
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  </property>
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  <property name="windowTitle">
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   <string>线程</string>
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  </property>
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  <layout class="QVBoxLayout" name="m_layout">
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   <item>
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    <widget class="QPushButton" name="m_btnStart">
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     <property name="sizePolicy">
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      <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
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       <horstretch>0</horstretch>
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       <verstretch>0</verstretch>
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      </sizepolicy>
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     </property>
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     <property name="text">
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      <string>启动</string>
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     </property>
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     <property name="default">
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      <bool>true</bool>
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     </property>
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    </widget>
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   </item>
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   <item>
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    <widget class="QPushButton" name="m_btnStop">
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     <property name="enabled">
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      <bool>false</bool>
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     </property>
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     <property name="sizePolicy">
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      <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
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       <horstretch>0</horstretch>
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       <verstretch>0</verstretch>
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      </sizepolicy>
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     </property>
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     <property name="text">
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      <string>停止</string>
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     </property>
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    </widget>
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   </item>
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  </layout>
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 </widget>
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 <resources/>
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 <connections/>
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</ui>

78.3 实现功能

78.3.1 工作线程

C:\Users\Minwei\Projects\Qt\Thread\workthread.h：

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#ifndef WORKTHREAD_H
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#define WORKTHREAD_H
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#include <QThread>
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class WorkThread : public QThread
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{
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public:
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    WorkThread(unsigned long msecs, char ch);
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    void stop();
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protected:
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    void run();
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private:
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    unsigned long m_msecs;
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    char m_ch;
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    bool m_stop;
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};
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#endif // WORKTHREAD_H

C:\Users\Minwei\Projects\Qt\Thread\workthread.cpp：

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#include <iostream>
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using namespace std;
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#include "workthread.h"
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WorkThread::WorkThread(unsigned long msecs, char ch)
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    : m_msecs(msecs)
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    , m_ch(ch)
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    , m_stop(false)
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{
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}
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void WorkThread::stop()
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{
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    m_stop = true;
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}
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void WorkThread::run()
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{
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    while (!m_stop)
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    {
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        cout << m_ch << flush;
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        msleep(m_msecs);
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    }
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}

78.3.2 主窗口

C:\Users\Minwei\Projects\Qt\Thread\threaddialog.h：

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#ifndef THREADDIALOG_H
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#define THREADDIALOG_H
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#include <QDialog>
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#include "workthread.h"
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QT_BEGIN_NAMESPACE
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namespace Ui { class ThreadDialog; }
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QT_END_NAMESPACE
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class ThreadDialog : public QDialog
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{
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    Q_OBJECT
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public:
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    ThreadDialog(QWidget *parent = nullptr);
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    ~ThreadDialog();
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private slots:
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    void on_m_btnStart_clicked();
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    void on_m_btnStop_clicked();
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private:
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    Ui::ThreadDialog *ui;
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    WorkThread* m_work1;
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    WorkThread* m_work2;
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};
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#endif // THREADDIALOG_H

C:\Users\Minwei\Projects\Qt\Thread\threaddialog.cpp：

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#include "threaddialog.h"
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#include "ui_threaddialog.h"
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ThreadDialog::ThreadDialog(QWidget *parent)
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    : QDialog(parent)
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    , ui(new Ui::ThreadDialog)
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    , m_work1(Q_NULLPTR)
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    , m_work2(Q_NULLPTR)
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{
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    ui->setupUi(this);
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}
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ThreadDialog::~ThreadDialog()
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{
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    delete ui;
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}
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void ThreadDialog::on_m_btnStart_clicked()
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{
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    ui->m_btnStart->setEnabled(false);
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    ui->m_btnStop->setEnabled(true);
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    m_work1 = new WorkThread(500, '|');
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    m_work1->start();
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    m_work2 = new WorkThread(100, '.');
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    m_work2->start();
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}
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void ThreadDialog::on_m_btnStop_clicked()
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{
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    m_work1->stop();
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    m_work1->wait();
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    delete m_work1;
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    m_work1 = Q_NULLPTR;
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    m_work2->stop();
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    m_work2->wait();
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    delete m_work2;
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    m_work2 = Q_NULLPTR;
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    ui->m_btnStart->setEnabled(true);
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    ui->m_btnStop->setEnabled(false);
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}

78.4 测试验证

运行效果如图所示：