Qt5.9继承QObject创建多线程实例
本文主要介绍了Qt5.9继承QObject创建多线程实例,文中通过示例代码介绍的非常详细,具有一定的参考价值,感兴趣的小伙伴们可以参考一下
本博客主要总结Qt中创建多线程的另一种方法,不是通过继承类QThread,而是通过继承对象QObject,来实现多线程。(可以直接跳过下面内容,看1.1内容)
利用继承QObject方法创建多线程,主要的步骤有一下几点:(注意:退出线程循环后,还要调用QThread::quit()函数,该线程才会触发QThread::finished()信号)
a1:首先创建一个类MyThread,基类为QObject。
a2:在类MyThread中创建一个槽函数,用于运行多线程里面的代码。所有耗时代码,全部在这个槽函数里面运行。
a3:实例一个QThread线程对象(容器),将类MyThread的实例对象转到该容器中,用函数void QObject::moveToThread(QThread *thread);
1 | myObjectThread->moveToThread(firstThread); |
a4:用一个信号触发该多线程槽函数,比如用QThread::started()信号。
1 | connect(firstThread,SIGNAL(started()),myObjectThread,SLOT(startThreadSlot())); |
a5:用信号QThread::finished绑定槽函数QThread::deleteLatater(),在线程退出时,销毁该线程和相关资源。
1 | connect(firstThread,SIGNAL(finished()),firstThread,SLOT(deleteLater())); |
a6:所有线程初始化完成后,启动函数QThread::start()开启多线程,然后自动触发多线程启动信号QThread::started()。
具体的教程如下图所示:
1.1新建一个widget工程,不要勾选ui界面。然后分别在mythread.h,mythread.cpp,widget.h,widget.cpp,main.cpp分别添加如下代码。
mythread.h
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | #ifndef MYTHREAD_H #define MYTHREAD_H #include <QObject> class MyThread : public QObject { Q_OBJECT public : explicit MyThread(QObject *parent = nullptr); void closeThread(); signals: public slots: void startThreadSlot(); private : volatile bool isStop; }; #endif // MYTHREAD_H |
mythread.cpp
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | #include "mythread.h" #include <QDebug> #include <QThread> MyThread::MyThread(QObject *parent) : QObject(parent) { isStop = false ; } void MyThread::closeThread() { isStop = true ; } void MyThread::startThreadSlot() { while (1) { if (isStop) return ; qDebug()<< "MyThread::startThreadSlot QThread::currentThreadId()==" <<QThread::currentThreadId(); QThread::sleep(1); } } |
widget.h
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 | #ifndef WIDGET_H #define WIDGET_H #include <QWidget> #include <QVBoxLayout> #include <QPushButton> #include <QThread> #include "mythread.h" class Widget : public QWidget { Q_OBJECT public : Widget(QWidget *parent = 0); ~Widget(); void createView(); private slots: void openThreadSlot(); void closeThreadSlot(); void finishedThreadSlot(); private : QVBoxLayout *mainLayout; QThread *firstThread; MyThread *myObjectThread; }; #endif // WIDGET_H |
widget.cpp
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 | #include <QDebug> #include "widget.h" Widget::Widget(QWidget *parent) : QWidget(parent) { createView(); } Widget::~Widget() { } void Widget::createView() { /*UI界面*/ mainLayout = new QVBoxLayout( this ); QPushButton *openThreadBtn = new QPushButton(tr( "打开线程" )); QPushButton *closeThreadBtn = new QPushButton(tr( "关闭线程" )); mainLayout->addWidget(openThreadBtn); mainLayout->addWidget(closeThreadBtn); mainLayout->addStretch(); connect(openThreadBtn,SIGNAL(clicked( bool )), this ,SLOT(openThreadSlot())); connect(closeThreadBtn,SIGNAL(clicked( bool )), this ,SLOT(closeThreadSlot())); } void Widget::openThreadSlot() { /*开启一条多线程*/ qDebug()<<tr( "开启线程" ); firstThread = new QThread; //线程容器 myObjectThread = new MyThread; myObjectThread->moveToThread(firstThread); //将创建的对象移到线程容器中 connect(firstThread,SIGNAL(finished()),myObjectThread,SLOT(deleteLater())); //终止线程时要调用deleteLater槽函数 connect(firstThread,SIGNAL(started()),myObjectThread,SLOT(startThreadSlot())); //开启线程槽函数 connect(firstThread,SIGNAL(finished()), this ,SLOT(finishedThreadSlot())); firstThread->start(); //开启多线程槽函数 qDebug()<< "mainWidget QThread::currentThreadId()==" <<QThread::currentThreadId(); } void Widget::closeThreadSlot() { qDebug()<<tr( "关闭线程" ); if (firstThread->isRunning()) { myObjectThread->closeThread(); //关闭线程槽函数 firstThread->quit(); //退出事件循环 firstThread->wait(); //释放线程槽函数资源 } } void Widget::finishedThreadSlot() { qDebug()<<tr( "多线程触发了finished信号123" ); } |
main.cpp
1 2 3 4 5 6 7 8 9 10 11 12 | #include "widget.h" #include <QApplication> int main( int argc, char *argv[]) { QApplication a(argc, argv); Widget w; w.resize(960,640); w.show(); return a.exec(); } |
1.2程序构建和运行后,结果如下图所示:
开启多线程
关闭多线程
参考内容:
https://blog.csdn.net/qq_41672557/article/details/80324251(重点参考步骤)
https://blog.csdn.net/czyt1988/article/details/71194457(重点参考代码)
到此这篇关于Qt5.9继承QObject创建多线程实例的文章就介绍到这了
原文链接:https://blog.csdn.net/naibozhuan3744/article/details/81201502