Qt 多线程（QThreadPool）

开发环境 Qt5.5.1、Qt Creator 3.5.1 

#include <QCoreApplication>

#include <QObject>

#include <QDebug>

#include <QThread>

#include <QThreadPool>

#include <QPointer>

class MyRunnable;

//事件类

class MyEvent: public QEvent {

public:

    MyRunnable *m_runnable;

    QString m_message;

    MyEvent(MyRunnable *r, QString message): QEvent(eventType()), m_runnable(r), m_message(message) { }

    static QEvent::Type eventType(){

        if(s_eventType == QEvent::None) {

            //注册一个自定义类型1000-65535

            s_eventType = (QEvent::Type)registerEventType();

            //qDebug()<<"registerEventType "<<(int)s_eventType;

        }

        return s_eventType;

    }

private:

    static QEvent::Type s_eventType;

};

QEvent::Type MyEvent::s_eventType = QEvent::None;

//线程的耗时操作

class MyRunnable :public QRunnable{

public:

    MyRunnable(QObject* observer): m_observer(observer){

    }

    //Override

    void run();

private:

    //QPointer是为QObject对象提供保护指针的模板类

    //一个保护指针 QPointer,行为类似正常的C++指针，只不过其在引用对象删除之后会自动设置为0. T必须是QObject的子类

    //保护指针在你要保存别人创建的QObject对象，且有可能其已经被删除而你仍然持有其引用的时候非常有用。

    //Qt也提供QSharedPointer,一个基于引用计数的共享指针对象实现，其能使用单个指针用于维护一个引用集合

    //就是说，如果指代的对象被删除，则后面对该对象的所有操作不会执行，因此也不会抛异常

    QPointer<QObject> m_observer;

};

//Override

void MyRunnable::run() {

    QString message;

    message.append(QString::number((int)QThread::currentThreadId())+" start\r\n");

    message.append(QThread::currentThread()->objectName()+"\r\n");

    QThread::sleep(1);

    message.append(QString::number((int)QThread::currentThreadId())+" end\r\n");

    QCoreApplication::postEvent(m_observer, new MyEvent(this, message));

}

//主程序中的消息处理程序

class MyProcesser: public QObject {

public:

    MyProcesser() {

    }

    //Override

    bool event(QEvent *);

    void process();

    void abort();

private:

    QList<MyRunnable*> m_runnableList;

};

bool MyProcesser::event(QEvent *e) {

    if(e->type() == MyEvent::eventType()) {

        qDebug()<<"processer get event, type is "<<(int)e->type();

        qDebug()<<((MyEvent*)e)->m_message;

        m_runnableList.removeOne(((MyEvent*)e)->m_runnable);

    }

}

void MyProcesser::process() {

    MyRunnable* runnable = new MyRunnable(this);

    m_runnableList.append(runnable);

    //是否线程池替你删除

    //If auto-deletion is enabled, QThreadPool will automatically delete this runnable after calling run();

    //otherwise, ownership remains with the application programmer.

    runnable->setAutoDelete(false);

    QThreadPool::globalInstance()->start(runnable);

}

void MyProcesser::abort() {

    int size = m_runnableList.size();

    MyRunnable* r;

    for(int i=0;i<size;i++) {

        r = m_runnableList.at(i);

        m_runnableList.removeAt(i);

    }

}

int main(int argc, char *argv[])

{

    QCoreApplication a(argc, argv);

    qDebug()<<"main thread "<<QThread::currentThreadId()<<" start";

    qDebug()<<"main thread "<<QThread::currentThread()->objectName();

    MyProcesser processer;

    processer.process();

    processer.process();

    return a.exec();

}

文章来源: blog.csdn.net，作者：福州-司马懿，版权归原作者所有，如需转载，请联系作者。

原文链接：blog.csdn.net/chy555chy/article/details/51560234