QT多线程的两种创建方法

Qt有两种多线程的方法，其中一种是继承QThread的run函数，另外一种是把一个继承于QObject的类转移到一个Thread里。
Qt4.8之前都是使用继承QThread的run这种方法，但是Qt4.8之后，Qt官方建议使用第二种方法。两种方法用起来都比较方便，但继承QObject的方法更加灵活。这里要记录的是如何正确的创建一个线程。

值得注意的是第一种方法只有run()里面在新的线程里，第二种方法就可以在新线程中调用函数
下一个博客讲怎么用互斥锁进行线程同步
//mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

extern int globalCount ;

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    qDebug()<<tr("主线程id:")<<QThread::currentThreadId();
    
    //多线程方式1
    myThread = new MyThread();//继承QThread
    myThread->start();

    //多线程方式2
    myThread1 = new MyThread1();//继承QObject
    thread1 = new QThread;
    connect(thread1, SIGNAL(started()),myThread1, SLOT(doWork()));//个人推荐这种
    myThread1->moveToThread(thread1);
    thread1->start();

}

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

//mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include "mythread.h"
#include <QThread>
#include <QObject>
#include <QTimer>
#include "mythread1.h"

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

private slots:

private:
    Ui::MainWindow *ui;
    MyThread *myThread;
    MyThread1 *myThread1;
    QThread *thread1 ;
};

#endif // MAINWINDOW_H

//方式1：只有run函数内的属于新的线程
//MyThread.cpp

#include "mythread.h"

extern int globalCount ;

MyThread::MyThread()
{
    isStop = true;
}

void MyThread::closeThread()
{
    isStop = true;
}

void MyThread::run()//只有run()里面在新的线程里
{


    qDebug()<<tr("mythread QThread::currentThreadId()==")<<QThread::currentThreadId();
    isStop = false;

//这种方式还是相当于在主线程里面执行
//    timer= new QTimer(NULL);
//    connect(timer, SIGNAL(timeout()), this, SLOT(onTimeout()));
//    timer->start(1000);
//    this->exec();
    while(1)
    {
        if(isStop)
        {
            return;
        }
        qDebug()<<"globalCount: " << ++globalCount <<QThread::currentThreadId();

        sleep(1);//QThread
    }
}

//这种方式还是相当于在主线程里面执行
void MyThread::onTimeout()
{
    qDebug()<<tr("mythread QThread::currentThreadId()==")<<QThread::currentThreadId();
    qDebug()<<"globalCount: " << ++globalCount;

}

//MyThread.h

#ifndef MYTHREAD_H
#define MYTHREAD_H

#include <QObject>
#include <QThread>
#include <QDebug>
#include <QTimer>

class MyThread : public QThread
{
    Q_OBJECT
public:
    explicit MyThread();
    void run();//重写基类的run函数
    void closeThread();

signals:

public slots:
    void onTimeout();
private:
    QTimer * timer;
    bool isStop = true;
};

#endif // MYTHREAD_H

//MyThread1.cpp

#include "mythread1.h"
#include <QMutex>

extern QMutex mutex;
QMutex mutex1;
extern int globalCount ;

MyThread1::MyThread1(QObject *parent) : QObject(parent)
{
    isStop = true;
}

void MyThread1::closeThread()
{
    isStop = true;
}

void MyThread1::doWork()
{
    qDebug()<<tr("mythread2 QThread::currentThreadId()==")<<QThread::currentThreadId();
    isStop = false;

    //定时方式1:(都是在子线程中)
    timer= new QTimer(this);
    connect(timer, SIGNAL(timeout()), this, SLOT(onTimeout()));
    timer->start(1000);

    //定时方式2:(都是在子线程中)
//    while(1)
//    {
//        if(isStop)
//        {
//            return;
//        }

//        QMutexLocker locker(&mutex);
//        qDebug()<<"globalCount: " << ++globalCount <<QThread::currentThreadId();

//        Sleep(1000);//<windows.h>,大写的S,单位是微秒
//    }
}

void MyThread1::onTimeout()
{
    QMutexLocker locker(&mutex1);
    qDebug()<<"globalCount: " << ++globalCount <<QThread::currentThreadId();

}

//MyThread1.h

#ifndef MYTHREAD1_H
#define MYTHREAD1_H

#include <QObject>
#include <QThread>
#include <QDebug>
#include <QTimer>
#include <windows.h>//Sleep(1);大写的S



class MyThread1 : public QObject
{
    Q_OBJECT
public:
    explicit MyThread1(QObject *parent = 0);
    void closeThread();
signals:

public slots:
    void doWork();
    void onTimeout();
private:
    QTimer * timer;
    bool isStop = true;
};

#endif // MYTHREAD1_H

QT多线程的两种创建方法

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