Qt realizes multithreading

There are two ways to implement multithreading in Qt:
 (1) Inherit QThread and rewrite the run() method
 (2) Use moveToThread()

This article only uses the second method to achieve multithreading

Creation steps

1. Create a new thread project

2. Add a new class MyWork

Right-click the project -> add new file -> C++ Class -> enter the class name MyWork, inherited from QObject -> OK.

The functions (functions) we need to implement can be placed in this MyWork class

3. Add a slot function to MyWork

Declare two slot functions in mywork.h

private slots:
    void weima();//Feed the horse
    void pichai();//firewood

Implement them in mywork.cpp

void MyWork::weima()
{
    qDebug()<<"I want to feed the horse..."<<"thread ID:"<<QThread::currentThreadId();
}
void MyWork::pichai()
{
    qDebug()<<"I want to chop wood..."<<"thread ID:"<<QThread::currentThreadId();
}

Add header file

#include <QDebug>
#include <QThread>

4. Use moveToThread()

Declare two variables in mainwindow.h

private:
    Ui::MainWindow *ui;
    QThread *t;
    MyWork *mw;

mainwindow.cpp

	t = new QThread();
    mw = new MyWork();
    mw->moveToThread(t);
    connect(t,SIGNAL(started()),mw,SLOT(weima()));
    connect(t,SIGNAL(started()),mw,SLOT(pichai()));
    
    qDebug()<<"Main thread id:"<<QThread::currentThreadId();

Add two buttons in mainwindow.ui

Click event of two buttons

void MainWindow::on_startButton_clicked()
{
    t->start();
    qDebug()<<"t start.";
}

void MainWindow::on_quitButton_clicked()
{
    t->quit();
    t->wait();
    qDebug()<<"t quit.";
}

Run successfully

As you can see, the ID of the main thread and the ID of thread t are different.
Since the two events are placed in one thread, they are the same.

You can create a new class DoSports based on the same principle

Implement new functions

//dosports.h
private slots:
    void playFootball();
    void playBasketball();

Put it in another thread t2

//mainwindow.cpp
	t2 = new QThread();
    ds = new DoSports();
    ds->moveToThread(t2);
    connect(t2,SIGNAL(started()),ds,SLOT(playFootball()));
    connect(t2,SIGNAL(started()),ds,SLOT(playBasketball()));

Add buttons the same, separate controls

void MainWindow::on_startButton2_clicked()
{
    t2->start();
    qDebug()<<"t2 start.";
}

void MainWindow::on_quitButton2_clicked()
{
    t2->quit();
    t2->wait();
    qDebug()<<"t2 quit.";
}

operation result:

As you can see, the IDs of the two secondary threads are not the same