qt线程动态回调被调类中的函数

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本文介绍如何封装一个Qt线程，使其能在不同类中调用，并使用Lambda表达式实现在线程中回调被调用类的成员函数。通过在VS2010+Win7+Qt5.40环境下编译验证，适用于需要在线程中灵活调用类方法的场景。

1.需求

要求封装一个qt线程能在不同类中调用，并能回调被调用类中的函数

2.解决

尝试多种方法，最终决定采用动态加载lamda表达式的方法解决

3.代码

catthread.h

#ifndef CATTHREAD_H
#define CATTHREAD_H
#include <QtCore/QThread>
#include <functional>

class catthread : public QThread
{
    Q_OBJECT

public:
    catthread(QObject *parent);
    ~catthread(){}

public:
    void setCallback(std::function<void(void)> func); 

protected:
    virtual void run();

private:
     std::function<void(void)> m_func;
};

#endif // CATTHREAD_H

catthread.cpp

#include "catthread.h"

catthread::catthread(QObject *parent)
    : QThread(parent)
{
    m_func = nullptr;
}

void catthread::run()
{
    if (m_func != nullptr)
        m_func();
}

void catthread::setCallback(std::function<void(void)> func)
{
    m_func = func;
}

gui中调用和回调

mythread.h

#ifndef MYTHREAD_H
#define MYTHREAD_H

#include <QtWidgets/QMainWindow>
#include "ui_mythread.h"
#include "catthread.h"

class mythread : public QMainWindow
{
    Q_OBJECT

public:
    mythread(QWidget *parent = 0);
    ~mythread();

private slots:
    void on_func1Button_clicked();
    void on_func2Button_clicked();
    void on_func3Button_clicked();
    void thread_finish();

public:
    void func1();
    void func2();
    void func3();

private:
    Ui::mythreadClass ui;
    catthread m_thread;

public:
    int m_nvalue;
};

#endif // MYTHREAD_H

mythread.cpp

#include "mythread.h"
#include <QMessageBox>

mythread::mythread(QWidget *parent)
    : QMainWindow(parent),m_thread(parent)
{
    ui.setupUi(this);
    connect(&m_thread, SIGNAL(finished()), this, SLOT(thread_finish()));
}

mythread::~mythread()
{

}

void mythread::func1()
{
    m_nvalue = 10;
}

void mythread::func2()
{
    m_nvalue = 20;
}

void mythread::func3()
{
    m_nvalue = 30;
}

void mythread::on_func1Button_clicked()
{
    if (!m_thread.isRunning())
    {
        auto func = [&](){func1();};
        m_thread.setCallback(func);
        m_thread.start();
    }
}

void mythread::on_func2Button_clicked()
{
    if (!m_thread.isRunning())
    {
        auto func = [&](){func2();};
        m_thread.setCallback(func);
        m_thread.start();
    }
}

void mythread::on_func3Button_clicked()
{
    if (!m_thread.isRunning())
    {
        auto func = [&](){func3();};
        m_thread.setCallback(func);
        m_thread.start();
    }
}

void mythread::thread_finish()
{
    QString strMsg("");
    strMsg = QString("%1").arg(m_nvalue);
    QMessageBox::information(this, "msg", strMsg);
}

main.cpp

#include "mythread.h"
#include <QtWidgets/QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    mythread w;
    w.show();
    return a.exec();
}