1、多线程示例

中间需要注意的地方：
1、代码中中文的忌讳，代码中文要么编译不过，要么显示为乱码，如果要显示中文可以在ui文件中修改为中文。
对于代码生成界面的最好只是用英文。
2、类名与数组名同名的忌讳，数组名与类名相同时会混淆导致编译错误，因为数组 []和类构造()使用时无法区分是谁。所以变量名与类名不可以相同。

threaddialog.h

#ifndef THREADDIALOG_H
#define THREADDIALOG_H

#include <QDialog>
#include <QPushButton>
#include "WorkThread.h"
#define MAXSIZE 5
QT_BEGIN_NAMESPACE
namespace Ui { class ThreadDialog; }
QT_END_NAMESPACE

class ThreadDialog : public QDialog
{
    Q_OBJECT

public:
    ThreadDialog(QWidget *parent = nullptr);
    ~ThreadDialog();

public slots:
    void slotStart();
    void slotStop();


private:
    Ui::ThreadDialog *ui;
    QPushButton *startBtn;
    QPushButton *stopBtn;
    QPushButton *quitBtn;
    WorkThread *workthread[MAXSIZE];

};
#endif // THREADDIALOG_H

WorkThread.h

#ifndef WorkThread_H
#define WorkThread_H
#include <QThread>

class WorkThread:public QThread
{
public:
    WorkThread();

protected:
    void run();
};

#endif // WorkThread_H

main.cpp

#include "threaddialog.h"

#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    ThreadDialog w;
    w.show();
    return a.exec();
}

threaddialog.cpp

#include "threaddialog.h"
#include "ui_threaddialog.h"
#include <QHBoxLayout>
ThreadDialog::ThreadDialog(QWidget *parent)
    : QDialog(parent)
    , ui(new Ui::ThreadDialog)
{
    ui->setupUi(this);
    setWindowTitle(tr("Thread"));
    startBtn = new QPushButton(tr("Start"));
    stopBtn = new QPushButton(tr("Stop"));
    quitBtn = new QPushButton(tr("Quit"));
    QHBoxLayout *mainLayout = new QHBoxLayout(this);
    mainLayout->addWidget(startBtn);
    mainLayout->addWidget(stopBtn);
    mainLayout->addWidget(quitBtn);

    connect(startBtn, SIGNAL(clicked()), this, SLOT(slotStart()) );
    connect(stopBtn, SIGNAL(clicked()), this, SLOT(slotStop()) );
    connect(quitBtn, SIGNAL(clicked()), this, SLOT(close()) );
}

ThreadDialog::~ThreadDialog()
{
    delete ui;
}

void ThreadDialog::slotStart()
{
    for (int i = 0; i < MAXSIZE ; i++ ) {
        workthread[i] = new WorkThread();

    }
    for (int i = 0; i < MAXSIZE ; i++ ) {
        workthread[i]->start();
    }
    startBtn->setEnabled(false);
    stopBtn->setEnabled(true);
}

void ThreadDialog::slotStop()
{
    for (int i = 0; i < MAXSIZE ; i++ ) {
        workthread[i]->terminate();
        workthread[i]->wait();
    }
    startBtn->setEnabled(true);
    stopBtn->setEnabled(false);
}

WorkThread.cpp

#include "WorkThread.h"
#include <QtDebug>
WorkThread::WorkThread()
{

}

void WorkThread::run()
{
    while(true)
    {
        for(int n = 0; n < 10; n++)
        {
            qDebug() << n << n << n << n << n << n << n << n ;
        }
    }
}