技術標籤：學習qt

Qt庫 執行緒

方式一、繼承QThread

步驟：

1. 自定義繼承於QThread的執行緒類
2. 定義執行緒物件
3. 呼叫start()介面啟動執行緒
4. 定義執行緒結束槽函式
5. 定義執行緒關閉槽函式
6. 繫結執行緒結束訊號與執行緒結束槽函式
7. 繫結視窗關閉訊號和執行緒關閉槽函式

程式碼示例：

1. 自定義執行緒類

/*mythred.h*/
#ifndef MYTHREAD_H
#define MYTHREAD_H
#include <QThread>
class MyThread : public QThread
{
    Q_OBJECT
public:
    explicit MyThread(QObject * parent=0);
    ~MyThread();
protected:
    void run();
signals:
    void isDone();
public slots:
};
#endif // MYTHREAD_H
/*mythred.cpp*/
#include "mythread.h"
MyThread::MyThread(QObject * parent)
{
}
MyThread::~MyThread()
{
}
void MyThread::run()
{
    sleep(5);
    emit isDone();
}
 

2. 介面顯示類

/*widget.h*/
#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
#include"mythread.h"
QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE
class Widget : public QWidget
{
    Q_OBJECT
public:
    Widget(QWidget *parent = nullptr);
    ~Widget();

    void dealTimeout();
    void dealDone();
    void stopThread();
private slots:
    void on_pushButton_clicked();
private:
    Ui::Widget *ui;
    QTimer *myTimer;
    MyThread *thread;
};
#endif // WIDGET_H
/*widget.cpp*/
#include "widget.h"
#include "ui_widget.h"
#include <QTimer>
#include <QDebug>
#include<QThread>
Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
    myTimer = new QTimer(this);
    thread = new MyThread(this);
    connect(thread, &MyThread::isDone,this,&Widget::dealDone);
    connect(this, &Widget::destroyed, this, &Widget::stopThread);
    connect(myTimer, &QTimer::timeout, this, &Widget::dealTimeout);
}
Widget::~Widget()
{
    delete ui;
}
void Widget::on_pushButton_clicked()
{
    if(!myTimer->isActive()){
        myTimer->start(100);
    }
    thread->start();
}
void Widget::dealTimeout()
{
    static int i = 0;
    i++;
    ui->lcdNumber->display(i);
}
void Widget::dealDone()
{
    qDebug() << "it is over";
    myTimer->stop();
}
void Widget::stopThread()
{
    thread->quit();
    thread->wait();
}

 

3. 介面佈局
   

方式二、繼承QObject

步驟：

1. 自定義繼承於QObject的執行緒類MyThread
2. 定義自定義執行緒類（子執行緒）及介面類（主執行緒）訊號
3. 建立QThread主執行緒物件和自定義子執行緒物件
4. 繫結子執行緒訊號與主執行緒定義的訊號處理函式
5. 繫結主執行緒訊號與子執行緒執行緒函式
6. 把自定義執行緒類MyThread加到主執行緒QThread

程式碼示例：

1. 自定義執行緒類

   /*mythread.h*/
   #ifndef MYTHREAD_H
   #define MYTHREAD_H
   #include <QObject>
   class MyThread : public QObject
   {
       Q_OBJECT
   public:
       explicit MyThread(QObject *parent = nullptr);
       ~MyThread();
       void run();
       void start();
       void stop();
   signals:
       void myThreadrun();
   public slots:
   private:
       bool isRun;
   };
   #endif // MYTHREAD_H
   
   /*mythread.cpp*/
   #include "mythread.h"
   #include<QDebug>
   #include<QThread>
   MyThread::MyThread(QObject *parent) : QObject(parent)
   {
    }
   MyThread:: ~MyThread()
   {
   }
   void MyThread::start()
   {
       qDebug()<<"start";
       this->isRun = true;
   }
   void MyThread::stop()
   {
       qDebug()<<"stop";
       this->isRun = false;
   }
   void MyThread::run()
   {
       while(isRun){
           QThread::sleep(1);
           emit myThreadrun();
           qDebug() << "子執行緒：" << QThread::currentThread();
           if(!isRun)
               break;
       }
   }
    
   

2. 介面顯示類

   /*widget.h*/
   #ifndef WIDGET_H
   #define WIDGET_H
   #include <QWidget>
   #include  "mythread.h"
   QT_BEGIN_NAMESPACE
   namespace Ui { class Widget; }
   QT_END_NAMESPACE
   class Widget : public QWidget
   {
       Q_OBJECT
   public:
       Widget(QWidget *parent = nullptr);
       ~Widget();
       void dealSignal();
       void dealClose();
   signals:
       void startThread();
   private slots:
       void on_pushButtonStart_clicked();
       void on_pushButton_clicked();
   private:
       Ui::Widget *ui;
       MyThread *myT;
       QThread *thread;
   };
   #endif // WIDGET_H
   
   /*widget.cpp*/
   #include "widget.h"
   #include "ui_widget.h"
   #include<QThread>
   #include<QTimer>
   #include<QDebug>
   Widget::Widget(QWidget *parent)
       : QWidget(parent)
       , ui(new Ui::Widget)
   {
       ui->setupUi(this);
       myT = new MyThread;
       thread = new QThread(this);
       myT->moveToThread(thread);
       connect(myT,&MyThread::myThreadrun,this,&Widget::dealSignal);
       connect(this,&Widget::startThread,myT,&MyThread::run);
       qDebug() << "主執行緒：" << QThread::currentThread();
       connect(this,&Widget::destroyed,this,&Widget::dealClose);
   }
   Widget::~Widget()
   {
       delete ui;
   }
   void Widget::dealSignal()
   {
       static int i = 0;
       i++;
       ui->lcdNumber->display(i);
   }
   void Widget::on_pushButtonStart_clicked()
   {
       if(thread->isRunning())  {
           return;
       }
       thread->start();
       myT->start();
       emit startThread();
   }
   void Widget::on_pushButton_clicked()
   {
       if(!thread->isRunning())  {
           return;
       }
       myT->stop();
       thread->quit();
       thread->wait();
   }
   void Widget::dealClose()
   {
       on_pushButton_clicked();
       delete myT;
   }
   

3. 介面佈局