QT_QThread thread

QT_QThread线程

注意的是：Slot functions cannot be called from within a thread,否则会出现意想不到的错误,如调用w.show等！It is possible to signal a slot function to respond,That is, try to make threads independent,解耦合.
Design operations on windows,Put it in the tank to do it.Don't do it in a thread

头文件

#pragma once
#include <QThread>
#include <QMutex>
#include "opencv2/core.hpp" // Mat所在的头文件
class XVideoThread :public QThread    //单件模式,Don't use this class to create objects,Only make interface calls.
{
    

	Q_OBJECT  // Signals and slots are only valid

public:

	//单件模式 获取对象
	static XVideoThread* Get()  //via a static function;
	{
    
		static XVideoThread vt;  //This object only generates one,Call it the singleton pattern; 只能通过这个get方式获取对象,进行调用,保证 对象具有唯一性.
		return &vt;  //返回指针类型
	}
	void Play() {
     mutex.lock(); isPlay = true; mutex.unlock(); }; //打开视频
	void Pause() {
     mutex.lock(); isPlay = false; mutex.unlock(); };
	
	~XVideoThread();

	//线程入口函数
	void run();

signals:
	
protected:  
	QMutex mutex;  //线程互斥
	XVideoThread();   //Constructors are placed in guards,You cannot use this class to generate objects externally.
};


/* How to use this singleton pattern？ 接口调用方法： XVideoThread::Get()获取这个对象vt,Then call the member function of this object through the pointerOpen. if (!XVideoThread::Get()->Open(file)) { QMessageBox::information(this, "error", name+" open failed!"); return; } */

源文件

#include "XVideoThread.h"
#include <opencv2/imgcodecs.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/imgproc.hpp>
#include <iostream>
#include "XFilter.h"
using namespace std;
using namespace cv;

void XVideoThread::run()  //注意的是,当线程被销毁的时候,It is possible that this thread was not destroyed,Causes the program to be displayed when the program is closedshutdown掉.
{
    
	for (;;)
	{
    
		mutex.lock();  //lock principle,Call as late as possible,尽早退出
		if (isexit)
		{
    
			mutex.unlock();  //尽早退出,一定不能遗漏
			break; 
		}
		if (!isPlay)  //If it is on hold
		{
    
			mutex.unlock();
			msleep(5);
			continue;
		}
		msleep(s);  //根据fpsSet the frame interval
		mutex.unlock();  //Always remember to exit under all conditions
	}
}
XVideoThread::XVideoThread()
{
    
	start();  //线程启动.XVideoThread继承public QThread 这个类,XVideoThread中重载了void run();函数,则调用start()后,A thread will be created,并把run()The function becomes the entry function
}

XVideoThread::~XVideoThread()
{
    
// terminate(); //Terminate the thread violently.
	mutex.lock(); //The thread is locked first.
	isexit = true; //等待一次run()函数中for循环完毕后,将isexitThe flag position is true,run()函数结束. Equivalent to the thread exit operationquit(); .
	mutex.unlock();  //Thread unraveled
	wait();  //等待线程的退出！！！ You must wait here for the thread to finish executing and exit
}