Qt线程的简单使用

Posted 2020-09-07 stay hungry stay foolish

Qt中线程的一种创建方式，就是使用QObject::moveToThread()函数。如下，直接上源代码，可以把费时的任务放到doWork()方法里进行，不阻塞主线程。

 1 #ifndef WORKER_H
 2 #define WORKER_H
 3 
 4 #include <QObject>
 5 
 6 class Worker : public QObject
 7 {
 8     Q_OBJECT
 9 
10 public:
11     Worker();
12     ~Worker();
13 public slots:
14     void doWork();
15 private:
16     
17 };
18 
19 #endif // WORKERR_H

 1 #include "Worker.h"
 2 #include <QDebug>
 3 
 4 Worker::Worker()
 5 {
 6 
 7 }
 8 
 9 Worker::~Worker()
10 {
11 
12 }
13 void Worker::doWork()
14 {
15     for (int i = 0;i < 10000;i++)
16     {
17         qDebug() << i;
18     }
19 }

需要在主程序中，关联相应的信号和槽,

1 m_pWorker = new Worker;
2     m_pWorkerThread = new QThread(this);
3 
4     connect(m_pWorkerThread, SIGNAL(started()),m_pWorker, SLOT(doWork()));
5     connect(m_pWorkerThread, SIGNAL(finished()), m_pWorker, SLOT(deleteLater()));
6     m_pWorker->moveToThread(m_pWorkerThread);

同时在析构函数中，也要进行想要的资源释放，

 1 disconnect(m_pWorkerThread, SIGNAL(started()),m_pWorker, SLOT(doWork()));
 2     disconnect(m_pWorkerThread, SIGNAL(finished()), m_pWorker, SLOT(deleteLater()));
 3     if (m_pWorkerThread)
 4     {
 5         if (m_pWorkerThread->isRunning())
 6         {
 7             m_pWorkerThread->quit();
 8             m_pWorkerThread->wait();
 9         }
10         delete m_pWorkerThread;
11         m_pWorkerThread = NULL;
12     }
13     if (m_pWorker)
14     {
15         delete m_pWorker;
16         m_pWorker = NULL;
17     }

最后提一点，如果需要在doWork()函数传递参数中，涉及传递的参数是自定义的类型时，需要将其注册为元类型。

如下的示例，1.我将需要计算的数据先进行预处理之后，发送我自定义的geoDataReady信号。

2.在线程中进行几何计算，完成之后，又将计算完成之后的数据发送回主函数。如下。

1 qRegisterMetaType<std::vector<MyGeometry*>>("std::vector<MyGeometry* >");
2     //在线程中进行几何运算
3     m_pGeoWorker = new CMyWork;
4     connect(this, SIGNAL(geoDataReady(const std::vector<MyGeometry> &)), m_pGeoWorker, SLOT(get(const std::vector<MYGeometry* > &)));
5     connect(m_pGeoWorker, SIGNAL(geoResultCompleted(const std::vector<MYGeometry* > &)), this, SLOT(draw(const std::vector<MYGeometry* > &)));
6     connect(&m_geoThread, SIGNAL(finished()), m_pGeoWorker, SLOT(deleteLater()));
7     m_pGeoWorker->moveToThread(&m_geoThread);
8     m_geoThread.start();