c++ - 如何停止循环线程

Question

我想在发出信号时停止循环线程，所以这是我的代码

void  MyThread::stopWatchingThread()
{
    qDebug()<<"MyThread::stopWatchingThread()";    
    Keep_running=false;
    qDebug()<<"MyThread::stopWatchingThread Keep_running"<<Keep_running;
    ...
}

void MyThread::run()
{
  qDebug()<<"MyThread::run()";
  qDebug()<<"MyThread::run Keep_running"<<Keep_running;  
  while(Keep_running)
    {
     ...
     }
  qDebug()<<"MyThread::run Keep_running"<<Keep_running;
  Keep_running=false;
  qDebug()<<"MyThread::run Keep_running"<<Keep_running;
}

void Watcher::Init()
{
    WatchingThread=new MyThread(this->L_RootToWatch);
    connect(this,SIGNAL(stopmonotiring()),WatchingThread, SLOT(stopWatchingThread()));
...
}
void Watcher::StartWatching()
{
    WatchingThread->start();
}

void Watcher::StopWatching()
{
    emit stopmonotiring();        
}

所以一切顺利，但我的问题是 Keep_running永远得不到false MyThread::run() 中的值发射后 stopWatchingThread所以 while永远循环。 我错过了什么 ？ 任何帮助将不胜感激。

Answer 1

不要在 Qt 中显式创建线程类。相反，创建一个 worker 对象，将该对象移动到 QThread，然后在 QThread 上调用 start()。这是一个简单的例子:

class Worker : public QObject
{
  Q_OBJECT
public:
  Worker( QObject * parent = 0 )
    : QObject( parent )
  {}

public slots:
  void doWork( ... )
  { 
    // do work here
  }

  void stopMonitoring()
  { 
    emit finished();
  }

signals:
  void finished();
};

int main()
{
  Worker * w = new Worker();
  QThread * thread = new QThread();
  QObject::connect( w, SIGNAL(finished()), thread, SLOT(quit())
  QObject::connect( w, SIGNAL(finished()), w, SLOT(deleteLater())
  QObject::connect( thread, SIGNAL(finished()), thread, SLOT(deleteLater())
  w->moveToThread( thread );
  thread->start();

  // some other object emits a signal connected to the 'doWork()' slot.
}

我省略了一些标准的 QApplication 样板文件，但如果您使用的是 Qt，那么您已经拥有了。这应该可以帮助您入门。