一、功能说明

1、通过继承QThread，重写run的方式实现多线程

2、点击“开始”按钮启动子线程，同时通过信号槽的方式给子线程发送“开始”字符串；

3、子线程每隔1秒向主线程发送累加数；

4、点击"停止"按钮，通过函数调用的方式停止子线程；

二、项目创建

1、新建Qt Widgets应用，名称为ThreadRun，基类选择QMainWindow；

2、MainWindow.ui中放入两个Push Button按钮，第一个text改为“开始”，objectNme改为startButton，第二个text改为“停止”，objectNme改为stopButton；

3、添加新的C++类，名称为MyThread，基类设置为QThread

三、代码演示

1、MainWindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H#include <QMainWindow>
#include "MyThread.h"namespace Ui {
class MainWindow;
}class MainWindow : public QMainWindow
{Q_OBJECTpublic:explicit MainWindow(QWidget *parent = nullptr);~MainWindow();signals:void sendData(QString);private slots:void on_startButton_clicked();void on_stopButton_clicked();void doSendValue(int);private:Ui::MainWindow *ui;MyThread *m_myThread;
};#endif // MAINWINDOW_H

2、MainWindow.cpp

#include "MainWindow.h"
#include "ui_MainWindow.h"
#include <QDebug>
MainWindow::MainWindow(QWidget *parent) :QMainWindow(parent),ui(new Ui::MainWindow)
{ui->setupUi(this);qDebug() << "主线程id：" << QThread::currentThreadId();m_myThread = new MyThread(this);//接收子线程数据connect(m_myThread, &MyThread::sendValue, this, &MainWindow::doSendValue);//给子线程发送数据connect(this, &MainWindow::sendData, m_myThread, &MyThread::doSendData);ui->startButton->setEnabled(true);ui->stopButton->setEnabled(false);
}MainWindow::~MainWindow()
{if(m_myThread->isRunning()){m_myThread->stop();}m_myThread->quit(); //将子线程停止m_myThread->wait(); //等待子线程的运行结束后再停止delete ui;
}void MainWindow::on_startButton_clicked()
{emit sendData("开始");qDebug() << "主线程 startButtonid：" << QThread::currentThreadId();m_myThread->start(); //子线程开始，自动调用run()函数ui->startButton->setEnabled(false);ui->stopButton->setEnabled(true);
}void MainWindow::on_stopButton_clicked()
{qDebug() << "主线程 stopButtonid：" << QThread::currentThreadId();if(m_myThread->isRunning()){m_myThread->stop();ui->startButton->setEnabled(true);ui->stopButton->setEnabled(false);}}void MainWindow::doSendValue(int value)
{qDebug() << value << "doSendValue 线程id："<< QThread::currentThreadId();
}

3、MyThread.h

#ifndef MYTHREAD_H
#define MYTHREAD_H#include <QObject>
#include <QThread>
class MyThread : public QThread
{Q_OBJECT
public:explicit MyThread(QObject *parent = nullptr);public slots:void stop();void doSendData(QString);protected:void run();signals:void sendValue(int);private slots:void showValue();private:volatile bool stopped;int value;
};#endif // MYTHREAD_H

4、MyThread.cpp

#include "MyThread.h"
#include <QThread>
#include <QDebug>MyThread::MyThread(QObject *parent) : QThread (parent)
{stopped = false;qDebug() << "创建 子线程id：" << QThread::currentThreadId();
}void MyThread::stop()
{stopped = true;qDebug() << "stop 子线程id：" << QThread::currentThreadId();
}void MyThread::doSendData(QString str)
{qDebug() << str << "doSendData 子线程id：" << QThread::currentThreadId();
}void MyThread::run()
{value = 0;qDebug() << "run 子线程id：" << QThread::currentThreadId();while(!stopped){showValue();msleep(1000);  //延迟1秒      }stopped = false;
}void MyThread::showValue()
{qDebug() << value << "show子线程id："<< QThread::currentThreadId();emit sendValue(value); //数据发送给主线程value++;
}

5、其他不用更改