c++ - Qt - 当我在 qApp->processEvents() 期间关闭窗口时，程序仍在任务管理器中运行

Question

我的应用程序绘制图像并为其添加标签。当窗口在等待输入时关闭，应用程序仍然在后台运行。这是我的捕获标签的函数示例。我是否遗漏了一些让程序正常退出的东西？

 void CustomMainWindow::CaptureLabel(void){

     connect(measurementLabel,
             SIGNAL(mousePressSignal()),
             this,
             SLOT(mouseLabel()),
             Qt::DirectConnection
             );

     m_MouseCount = 0;
     m_CurrentLabel = cv::Point2f(0.0, 0.0);

     while(m_MouseCount < 1){
         qApp->processEvents();

     }

     disconnect(measurementLabel,
             SIGNAL(mousePressSignal()),
             this,
             SLOT(mouseLabel())
             );
 }

Answer 1

您可以轻松地使用状态机来指导您完成状态更改。这将消除您诉诸可怕的伪同步黑客的需要。

class CustomMainWindow : ... {
  QStateMachine m_CaptureLabelMachine;
  ...
};

void CustomMainWindow::CaptureLabel(void){
  if (!m_CaptureLabelMachine.findChild<QFinalState*>()) {
    // build the state machine
    auto machine = &m_CaptureLabelMachine;
    auto s1 = new QState(machine), s2 = new QFinalState(machine);
    machine->setInitialState(s1);
    s1->addTransition(measurementLabel, SIGNAL(mousePressSignal()), s2);
    connect(s1, &QState::entered, [this]{
      connect(measurementLabel, SIGNAL(mousePressSignal()), SLOT(mouseLabel()));
      m_MouseCount = 0;
      m_CurrentLabel = cv::Point2f(0.0, 0.0);
    });
    connect(s2, &QState::entered, [this]{
      disconnect(measurementLabel, SIGNAL(mousePressSignal()), SLOT(mouseLabel()));
    });
  }
  m_CaptureLabelMachine.start();
}