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1myThread = new MyThread();//继承QThreadmyThread->start();//多线程方式2myThread1 = new MyThread1();//继承QObjectthread1 = 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_OBJECTpublic: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Sclass 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