QT多线程

1. 写一个线程类，继承QThread

//workthread.h
#ifndef WORKTHREAD_H
#define WORKTHREAD_H

#include <QThread>

class WorkThread : public QThread
{
    Q_OBJECT
public:
    WorkThread();
protected:
    //重写run函数,业务逻辑写在该函数中
    void run();  
};

#endif // WORKTHREAD_H

//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;
    }
}

2、编写一个自定义Dialog

//threaddlg.h
#ifndef THREADDLG_H
#define THREADDLG_H

#include <QDialog>
#include <QPushButton>
#include "workthread.h"
#define MAXSIZE 5

class ThreadDlg : public QDialog
{
    Q_OBJECT

public:
    ThreadDlg(QWidget *parent = 0);
    ~ThreadDlg();    
private:
    QPushButton *startBtn;
    QPushButton *stopBtn;
    QPushButton *quitBtn;
public slots:
    void slotStart();
    void slotStop();
private:
    WorkThread *workThread[MAXSIZE];
};

#endif // THREADDLG_H

//threaddlg.cpp
#include "threaddlg.h"
#include <QHBoxLayout>

ThreadDlg::ThreadDlg(QWidget *parent)
    : QDialog(parent)
{
    setWindowTitle(tr("线程"));

    startBtn = new QPushButton(tr("开始"));
    stopBtn = new QPushButton(tr("停止"));
    quitBtn = new QPushButton(tr("退出"));

    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()));
}

ThreadDlg::~ThreadDlg()
{

}

void ThreadDlg::slotStart()
{
    for(int i=0;i<MAXSIZE;i++)
    {
        workThread[i]=new WorkThread();  
    }
    for(int i=0;i<MAXSIZE;i++)
    {
        workThread[i]->start();  //启动线程
    }
    startBtn->setEnabled(false);
    stopBtn->setEnabled(true);
}

void ThreadDlg::slotStop()
{
    for(int i=0;i<MAXSIZE;i++)
    {
        workThread[i]->terminate(); //终止线程，但是并不会马上，要根据系统调度
        workThread[i]->wait(); //阻塞线程，等待系统终止线程
    }
    startBtn->setEnabled(true);
    stopBtn->setEnabled(false);
}

注意：“在QThread中定义的所有东西都属于创建该QThread的线程。”，QT中继承Qthread类后,在类中定义的对象或或对象的指针都是属于主线程的。次线程正真意义上的实体内容实在实现run()函数里。所以，要将mythread线程里的对象或指针创建，需要在run()函数里,创建或分配对象空间。