QT 多线程（QThread）里调用线程池（QThreadPool ）与主界面进行通讯

在最近的一个项目中，遇到了一个问题，就是主界面调用一个线程，然后再线程中开启一个线程池进行数据生成，线程池调用的线程对象必须继承自QRunable类，这个类有个缺点，就是因为它无法继承QObject，所以不能向外面发送信号，但是我们需要在主界面显示它输出的信息。怎么办呢？

• 编写一个QRunable子类
• 编写一个QThread子类
• 调用QThread子类

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编写一个QRunable子类

编写一个QRunable子类MyRunable

MyRunable.h代码，如下：

#ifndef MYRUNNABLE_H#define MYRUNNABLE_H#include <QRunnable>#include <QMetaObject>class MyRunnable : public QRunnable{public:    MyRunnable(QObject *parent = 0);    ~MyRunnable();    void run();    void setID(const int &id);    //向外传送消息    void requestMsg(const QString &msg);private:    //父对象    QObject *mParent;    int runnableID;};#endif // MYRUNNABLE_H

MyRunable.cpp代码，如下：

#include "myrunnable.h"#include <QDebug>#include <QThread>MyRunnable::MyRunnable(QObject *parent)    : QRunnable(){    mParent = parent;}MyRunnable::~MyRunnable(){    runnableID = 0;}void MyRunnable::setID(const int &id){    runnableID = id;}void MyRunnable::requestMsg(const QString &msg){    QMetaObject::invokeMethod(mParent, "requestMsg", Qt::QueuedConnection, Q_ARG(QString, msg));}void MyRunnable::run(){    for(int i = 0;i < 10;i++)    {        requestMsg(QString("this is a MyRunnable %1").arg(runnableID));        QThread::sleep(1);    }}

编写一个QThread子类

编写一个QThread子类MyThread

MyThread.h代码，如下：

#ifndef MYTHREAD_H#define MYTHREAD_H#include <QThread>class MyThread : public QThread{    Q_OBJECTpublic:    explicit MyThread(QObject *parent = 0);protected:    void run();signals:    void requestMsg(const QString &msg);public slots:};#endif // MYTHREAD_H

MyThread.cpp代码，如下：

#include "mythread.h"#include <QThreadPool>#include "myrunnable.h"#include <QDebug>MyThread::MyThread(QObject *parent) :    QThread(parent){}void MyThread::run(){    qDebug() << "MyThread";    QThreadPool myPool;    myPool.setMaxThreadCount(4);    for(int i = 0;i < 4;i++)    {        MyRunnable *subThread = new MyRunnable(this);        subThread->setID(i);        myPool.start(subThread);    }    myPool.waitForDone();}

调用QThread子类

在MainWindow中调用MyThread并关联信号槽

MainWindow .h代码，如下：

#ifndef MAINWINDOW_H#define MAINWINDOW_H#include <QMainWindow>#include "mythread.h"namespace Ui {class MainWindow;}class MainWindow : public QMainWindow{    Q_OBJECTpublic:    explicit MainWindow(QWidget *parent = 0);    ~MainWindow();private slots:    void showMsg(const QString &msg);private:    Ui::MainWindow *ui;    MyThread myThread;};#endif // MAINWINDOW_H

MainWindow .cpp代码，如下：

#include "mainwindow.h"#include "ui_mainwindow.h"#include <QDebug>#include <QDateTime>#include <QThreadPool>#include <myrunnable.h>MainWindow::MainWindow(QWidget *parent) :    QMainWindow(parent),    ui(new Ui::MainWindow){    connect(&myThread,SIGNAL(requestMsg(const QString&)),this,SLOT(showMsg(const QString&)));    myThread.start();}void MainWindow::showMsg(const QString &msg){    qDebug()<< msg;}

运行结果

MyThread"this is a MyRunnable 0""this is a MyRunnable 1""this is a MyRunnable 2""this is a MyRunnable 3""this is a MyRunnable 0""this is a MyRunnable 1""this is a MyRunnable 2""this is a MyRunnable 3""this is a MyRunnable 0""this is a MyRunnable 1""this is a MyRunnable 2""this is a MyRunnable 3""this is a MyRunnable 0""this is a MyRunnable 1""this is a MyRunnable 2""this is a MyRunnable 3""this is a MyRunnable 0""this is a MyRunnable 1""this is a MyRunnable 2""this is a MyRunnable 3""this is a MyRunnable 0""this is a MyRunnable 1""this is a MyRunnable 2""this is a MyRunnable 3""this is a MyRunnable 0""this is a MyRunnable 1""this is a MyRunnable 2""this is a MyRunnable 3""this is a MyRunnable 0""this is a MyRunnable 1""this is a MyRunnable 2""this is a MyRunnable 3""this is a MyRunnable 0""this is a MyRunnable 1""this is a MyRunnable 2""this is a MyRunnable 3""this is a MyRunnable 0""this is a MyRunnable 1""this is a MyRunnable 2""this is a MyRunnable 3"

欢迎大家指正…