1.QThread：

继承QThread创建子线程的注意点：

（1）需要写一个继承QThread的子类，然后必须要重写继承的run()函数（在run函数里面重写要在线程中执行的方法（任务函数））

（2）创建这个子类的实例对象，然后调start()方法就可以让线程工作了

缺点：（1）如果要在一个继承QThread的子类里面重写run函数时，如果想一个run函数实现多个任务函数，那么这个run函数写起来就很复杂，不利于代码的可读性

2.使用QThread方法实现点击开始按钮生成10000个随机数，然后分别使用冒泡排序和快速排序排序这10000个随机数，最后在窗口显示排序后的数字：

mainwindow.h文件：

#ifndef MAINWINDOW_H
#define MAINWINDOW_H#include <QMainWindow>QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACEclass MainWindow : public QMainWindow
{Q_OBJECTpublic:MainWindow(QWidget *parent = nullptr);~MainWindow();
signals:void starting(int num);
private:Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H

mythread.h文件：

#ifndef MYTHREAD_H
#define MYTHREAD_H#include <QThread>
//生成随机数
class MyThread : public QThread
{Q_OBJECT
public:explicit MyThread(QObject *parent = nullptr);void recvNum(int num);
protected:void run() override;
signals:void sendArray(QVector<int> list);
private:int m_num;
};class BubbleSort : public QThread
{Q_OBJECT
public:explicit BubbleSort(QObject *parent = nullptr);void recvArray(QVector<int> list);
protected:void run() override;
signals:void finish(QVector<int> num);
private:QVector<int> m_list;
};class QuickSort : public QThread
{Q_OBJECT
public:explicit QuickSort(QObject *parent = nullptr);void recvArray(QVector<int> list);
private:void quickSort(QVector<int> &list, int l, int r);protected:void run() override;
signals:void finish(QVector<int> num);
private:QVector<int> m_list;};
#endif // MYTHREAD_H

mian.cpp文件：

#include "mainwindow.h"#include <QApplication>int main(int argc, char *argv[])
{QApplication a(argc, argv);qRegisterMetaType<QVector<int>>("QVector<int>");MainWindow w;w.show();return a.exec();
}

mainwindow.cpp文件： 

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "mythread.h"
MainWindow::MainWindow(QWidget *parent): QMainWindow(parent), ui(new Ui::MainWindow)
{ui->setupUi(this);//1.创建子线程的对象MyThread *gen = new MyThread;BubbleSort *bubble = new BubbleSort;QuickSort *quick = new QuickSort;connect(this, &MainWindow::starting, gen, &MyThread::recvNum);//2.启动子线程connect(ui->start, &QPushButton::clicked, this, [=]{emit starting(10000); //在启动子线程时，将要生成的随机数的个数发送出去gen->start();});//接收子线程发送的数据connect(gen, &MyThread::sendArray, bubble, &BubbleSort::recvArray);connect(gen, &MyThread::sendArray, quick, &QuickSort::recvArray);connect(gen, &MyThread::sendArray, this, [=](QVector<int> list){ //connect里面不支持传递QVector类型//需要使用qRegisterMetaType()进行注册bubble->start();quick->start();for(int i = 0; i < list.size(); i++){ui->randList->addItem(QString::number(list.at(i)));}});connect(bubble, &BubbleSort::finish, this, [=](QVector<int> list){ //connect里面不支持传递QVector类型//需要使用qRegisterMetaType()进行注册for(int i = 0; i < list.size(); i++){ui->bubbleList->addItem(QString::number(list.at(i)));}});connect(quick, &QuickSort::finish, this, [=](QVector<int> list){ //connect里面不支持传递QVector类型//需要使用qRegisterMetaType()进行注册for(int i = 0; i < list.size(); i++){ui->quickList->addItem(QString::number(list.at(i)));}});//窗口关闭时，释放资源//窗口关闭时，会发送一个destroyed()信号，就可以根据这个信号来销毁线程的资源connect(this, &MainWindow::destroyed, this,[=]{gen->quit();gen->wait();gen->deleteLater(); //delete gen 销毁线程gen的资源bubble->quit();bubble->wait();bubble->deleteLater(); //delete bubble 销毁线程t2的资源quick->quit();quick->wait();quick->deleteLater(); //delete quick 销毁线程quick的资源});\\
}MainWindow::~MainWindow()
{delete ui;
}

mythread.cpp文件：

#include "mythread.h"
#include <QVector>
#include <QElapsedTimer> //计算某个流程执行所使用的时间
#include <QDebug>
#include <QThread>
MyThread::MyThread(QObject *parent): QThread(parent)
{}void MyThread::recvNum(int num)
{m_num = num;
}void MyThread::run()
{qDebug() << "生成随机数的线程地址" << QThread::currentThread(); //获取一个指针，这个指针指向当前线程对象的地址QVector<int> list;QElapsedTimer time;time.start();for(int i = 0; i < m_num; i++){list.push_back(qrand() % 100000);}int milsec = time.elapsed();qDebug() << "生成" << m_num << "个随机数总共用时：" << milsec << "毫秒";emit sendArray(list);
}BubbleSort::BubbleSort(QObject *parent):QThread(parent)
{}void BubbleSort::recvArray(QVector<int> list)
{m_list = list;
}void BubbleSort::run()
{qDebug() << "冒泡排序的线程地址" << QThread::currentThread(); //获取一个指针，这个指针指向当前线程对象的地址QElapsedTimer time;time.start();for(int i = 0; i < m_list.size() - 1 ;i++){for(int j = 0;j < m_list.size() - i - 1; j++){if(m_list[j] > m_list[j + 1]){int temp = m_list[j];m_list[j] = m_list[j + 1];m_list[j + 1] = temp;}}}int milsec = time.elapsed();qDebug() << "冒泡排序用时" << milsec << "毫秒";emit finish(m_list);
}QuickSort::QuickSort(QObject *parent):QThread(parent)
{}void QuickSort::recvArray(QVector<int> list)
{m_list = list;
}void QuickSort::quickSort(QVector<int> &s, int l, int r)
{if(l < r){int i = l, j = r;int x = s[l];while(i < j){while(i < j &&s[j] >=x){j--;}if(i < j){s[i++] = s[j];}while(i < j && s[i] < x){i++;}if(i < j){s[j--] = s[i];}}s[i] = x;quickSort(s, l, i - 1);quickSort(s, i + 1, r);}
}void QuickSort::run()
{qDebug() << "快速排序的线程地址" << QThread::currentThread(); //获取一个指针，这个指针指向当前线程对象的地址QElapsedTimer time;time.start();quickSort(m_list, 0,m_list.size()-1);int milsec = time.elapsed();qDebug() << "快速排序用时" << milsec << "毫秒";emit finish(m_list);
}

运行结果：