c++ - QThread 终止和关联

Question

本例用于测试QThread。主要目标是能够在专用线程中运行一个耗时的阻塞方法，并且能够随时终止和重新启动线程。阻止方法是我们无法控制的第 3 方库。我知道 Qt 的文档不鼓励使用 QThread::terminate 但目前我看不到任何其他方式。

下面是在专用线程中运行所需代码的伪示例。基本上有一种方法可能需要 10-15 分钟来处理。在 QThread::termination 上添加 moveToThread 以将亲和性带回主线程或执行 processEvent 以处理 QThread::quit() 方法是不合逻辑的。

void run()
{
  // initiate variables
  thirdparty lib(var1, var2);
  int res = lib.execute(var3, var4, var6);
  // handle result and exit
}

在 Windows 7 上使用 Qt 4.7。

运行代码产生这个输出

Test::doWork thread: QThread(0x219e960) 
Test::started thread: QThread(0x239bce8)
Test::doTerminate thread: QThread(0x239bce8) 
Test::doWork thread: QThread(0x239bce8) 
QObject::moveToThread: Current thread (0x219e960) is not the object's thread (0x239bce8). Cannot move to target thread (0x239bd20)

moveToThread API 在第二次执行 Test::doWork() 方法时失败。这似乎是因为测试实例与另一个线程有关联(此时已终止)。我怎样才能改变亲和性？

终止和重启 QThread 的推荐方法是什么？我需要删除测试实例吗？

代码；

#include <QCoreApplication>
#include <QThread>
#include <iostream>
#include <QDebug>
#include "Worker.h"
#include "Windows.h"

class Test : public QObject
{
  Q_OBJECT
  QThread* m_thread;
  int      m_state;

public:
    Test() : m_thread(0), m_state(3) { }

public slots:
    void doWork()
    {
      qDebug() << "Test::doWork thread:" << QObject::thread();
      if (!m_thread)
      {
        m_thread = new QThread();
        QObject::moveToThread(m_thread);
        QObject::connect(m_thread, SIGNAL(started()), this, SLOT(started()));
        QObject::connect(m_thread, SIGNAL(finished()), this, SLOT(finished()));
        QObject::connect(m_thread, SIGNAL(terminated()), this, SLOT(terminated()));
        m_thread->start();
      }
    }

    void started()
    {      
      qDebug() << "Test::started thread:" << QObject::thread();
      Sleep(60);
    }

    void finished()
    {
      qDebug() << "Test::finished thread:" << QObject::thread();
    }

    void terminated()
    {
      qDebug() << "Test::terminated thread:" << QObject::thread();
    }

    void doTerminate()
    {
      qDebug() << "Test::doTerminate thread:" << QObject::thread();
      QObject::disconnect(m_thread);
      m_thread->terminate();
      m_thread->wait();
      m_thread = NULL;
    }

    int state()
    {
      return m_state;
    }
};

int main(int argc, char *argv[])
{
  QCoreApplication a(argc, argv);
  Test test;

  test.doWork();
  Sleep(10);

  test.doTerminate();
  Sleep(10);

  test.doWork();
  return a.exec();
}

Answer 1

除了使用 terminate，您可以调用更可接受的函数 quit()。