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 
#include 

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

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MyRunable.cpp代码，如下：

#include "myrunnable.h"
#include 
#include 
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);
    }
}

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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 

class MyThread : public QThread
{
    Q_OBJECT
public:
    explicit MyThread(QObject *parent = 0);

protected:
    void run();

signals:
    void requestMsg(const QString &msg);

public slots:

};

#endif // MYTHREAD_H

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MyThread.cpp代码，如下：

#include "mythread.h"
#include 
#include "myrunnable.h"
#include 
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();
}

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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 
#include "mythread.h"

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
private slots:
    void showMsg(const QString &msg);
private:
    Ui::MainWindow *ui;

    MyThread myThread;
};

#endif // MAINWINDOW_H

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MainWindow .cpp代码，如下：

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

#include 
#include 


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;
}

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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"

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欢迎大家指正…