【qt创建线程两种方式】-编程知识

QT使用线程的两种方式

1.案例进度条

案例解析：
如图由组件一个进度条和三个按钮组成，当点击开始的时候进度条由0%到100%，点击暂停，进度条保持之前进度，再次点击暂停变为继续，点击停止按钮进度条停止。
案例流程：
1.创建qwidget工程
2.添加四个控件，转到槽函数

在这里插入图片描述

2.使用线程方式一

2.1创建一个类继承QThread，重写run方法

2.2mythread.cpp

#include "mythread.h"
#include <QDebug>
MyThread::MyThread()
{}
void MyThread::stop()
{running=false;
}
//暂停继续
void MyThread::threadStop(bool flag)
{pause=flag;
}
//重写run方法
void MyThread::run()
{qDebug()<<"线程id:"<<currentThreadId();while (1) {//触发信号while(running){while (pause) {msleep(100);}if(value>100)value=0;emit valChage(value++);msleep(100);}exit(0);}
}

2.3mythread.h

#ifndef MYTHREAD_H
#define MYTHREAD_H
#include <QThread>
#include <QDebug>
//继承QThread重写run方法
class MyThread : public QThread
{Q_OBJECT
public slots:void stop();void threadStop(bool flag);
signals:void valChage(int);
public:MyThread();void run();
private:int value=0;bool running=true;bool pause=false;
};#endif // MYTHREAD_H

2.4widget.h

#ifndef WIDGET_H
#define WIDGET_H#include <QWidget>
#include <QProgressBar>
#include<QThread>
#include "mythread.h"
namespace Ui {
class Widget;
}class Widget : public QWidget
{Q_OBJECTpublic:explicit Widget(QWidget *parent = 0);~Widget();
signals:void stop();void threadStop(bool);
private slots:void on_pushButton_clicked();void on_pushButton_3_clicked();void on_pushButton_2_clicked();private:Ui::Widget *ui;MyThread *mythread;
};
#endif // WIDGET_H

2.5widget.cpp

#include "widget.h"
#include "ui_widget.h"
Widget::Widget(QWidget *parent) :QWidget(parent),ui(new Ui::Widget)
{ui->setupUi(this);}Widget::~Widget()
{delete ui;
}void Widget::on_pushButton_clicked(){mythread= new MyThread();//绑定信号与槽函数connect(mythread,&MyThread::valChage,ui->progressBar,&QProgressBar::setValue);//延时connect(mythread,&MyThread::finished,mythread, &QObject::deleteLater);connect(this,&Widget::stop,mythread,&MyThread::stop);connect(this,&Widget::threadStop,mythread,&MyThread::threadStop);mythread->start();ui->pushButton->setEnabled(false);}void Widget::on_pushButton_3_clicked()
{emit stop();
}
void Widget::on_pushButton_2_clicked()
{static bool flag=true;if(flag){emit threadStop(true);ui->pushButton_2->setText("继续");flag=false;}else{emit threadStop(false);ui->pushButton_2->setText("暂停");flag=true;}
}

3.使用线程方式二

3.1创建类继承QObject

在这里插入图片描述

3.2qworker.h

这里的槽函数实现直接写在.h文件中，不够规范，只便与学习观看，切不要效仿。

#ifndef QWORKER_H
#define QWORKER_H
#include <QObject>
#include <QThread>
#include <QApplication>
class qworker : public QObject
{Q_OBJECT
public:explicit qworker(QObject *parent = nullptr);signals:void dataChanged(int);
public slots:void doWorking(){while (!sFlag) {if(current>=100)current=0;while (pFlag) {QThread::msleep(10);//接收来自外部进程的事件，否则收不到信号QApplication::processEvents();}emit dataChanged(current++);QThread::msleep(10);QApplication::processEvents();}sFlag=false;current=0;}void pause(bool flag){pFlag=flag;}void stop(){sFlag=true;}
private://进度条int current=0;//暂停bool pFlag=false;//停止bool sFlag=false;
};
#endif // QWORKER_H

3.3widget.h

#ifndef WIDGET_H
#define WIDGET_H#include <QWidget>
//引入qworker.h
#include "qworker.h"namespace Ui {
class Widget;
}class Widget : public QWidget
{Q_OBJECTpublic:explicit Widget(QWidget *parent = 0);~Widget();
signals:void working();void pause(bool);void stop();
private slots:void on_pushButton_clicked();void on_pushButton_2_clicked();void on_pushButton_3_clicked();
c
private:Ui::Widget *ui;qworker *worker;QThread thread;
};
#endif // WIDGET_H

3.4widget.cpp

#include "widget.h"
#include "ui_widget.h"Widget::Widget(QWidget *parent) :QWidget(parent),ui(new Ui::Widget)
{ui->setupUi(this);worker=new qworker();//移动到线程中worker->moveToThread(&thread);//开始connect(this,&Widget::working,worker,&qworker::doWorking);//暂停connect(this,&Widget::pause,worker,&qworker::pause);//停止connect(this,&Widget::stop,worker,&qworker::stop);connect(worker,&qworker::dataChanged,ui->progressBar,&QProgressBar::setValue);thread.start();
}
Widget::~Widget()
{delete ui;
}
void Widget::on_pushButton_clicked()
{emit working();
}void Widget::on_pushButton_2_clicked()
{static bool flag=true;if(flag){emit pause(true);flag=false;ui->pushButton_2->setText("继续");}else{emit pause(false);flag=true;ui->pushButton_2->setText("暂停");}
}
void Widget::on_pushButton_3_clicked()
{emit stop();
}