Qt 应用程序挂起

Question

如何检测我的应用程序是否已暂停（当有人更改应用程序时）并通过停用计时器做出反应，然后在我的应用程序取消暂停时（当有人重新打开我的半运行应用程序时）重新激活它。下面是我到目前为止在我的应用程序的这一部分上编码的程度，但它给出了一个错误：“'QApplication::QApplication(const QApplication&)' is private”，它在 myapp.cpp 第 4 行的上下文中说。请如果任何人都可以告诉我我做错了什么，我将不胜感激。

这是我的 main.cpp 代码：

#include <QtGui/QApplication>
#include "qmlapplicationviewer.h"
#include <QObject>
#include <QGraphicsObject>
#include <QTimer>
#include <QVariant>
#include "timecontrol.h"
#include "scorecontrol.h"
#include "Retry.h"
#include <QEvent>

int main(int argc, char *argv[])
{
QApplication app(argc, argv);

QmlApplicationViewer viewer;
viewer.setOrientation(QmlApplicationViewer::ScreenOrientationLockLandscape);
viewer.setMainQmlFile(QLatin1String("qml/Raker/main.qml"));
viewer.showExpanded();

QObject *rootObject = viewer.rootObject();

QTimer *timmer = new QTimer;
timmer->setInterval(1000);

TimeControl *timcon = new TimeControl;

scorecontrol *scorer = new scorecontrol;

Retry *probeer = new Retry;

QObject::connect(timmer, SIGNAL(timeout()), timcon, SLOT(updateTime()));
QObject::connect(timcon, SIGNAL(setTime(QVariant)), rootObject, SLOT(setTime(QVariant)));
QObject::connect(rootObject, SIGNAL(blockClicked(int, int)), scorer, SLOT(checkRight(int, int)));
QObject::connect(scorer, SIGNAL(setScore(QVariant)), rootObject, SLOT(setScore(QVariant)));
QObject::connect(scorer, SIGNAL(setState(QVariant)), rootObject, SLOT(setState(QVariant)));

QObject::connect(rootObject, SIGNAL(start()), probeer, SLOT(Reetry()));
QObject::connect(probeer, SIGNAL(start()), timmer, SLOT(start()));
QObject::connect(probeer, SIGNAL(start(int)), scorer, SLOT(randomNum(int)));
QObject::connect(probeer, SIGNAL(sReset()), timcon, SLOT(reset()));
QObject::connect(probeer, SIGNAL(tReset()), scorer, SLOT(reset()));
QObject::connect(timcon, SIGNAL(timeOut()), scorer, SLOT(reset()));

QObject::connect(timcon, SIGNAL(setState(QVariant)), rootObject, SLOT(setState(QVariant)));
QObject::connect(timcon, SIGNAL(changeFinal()), scorer, SLOT(changeFinal()));
QObject::connect(scorer, SIGNAL(setFinal(QVariant)), rootObject, SLOT(setFinal(QVariant)));

return app.exec();
}

myApp.h:

    #ifndef MYAPP_H
    #define MYAPP_H

    #include <QApplication>
    #include <QObject>

    class MyApp : public QApplication
    {
    public:
        MyApp(QApplication &app);

    protected:
         bool eventFilter(QObject *obj, QEvent *event);
    };

    #endif // MYAPP_H

myapp.cpp:

    #include "myapp.h"
    #include <QEvent>

    MyApp::MyApp(QApplication &app) : QApplication(app)
    {
        installEventFilter(this);
    }

    bool MyApp::eventFilter(QObject *obj, QEvent *event)
    {
        if (event->type() == QEvent::ApplicationDeactivate)
        {

        }

        if (event->type() == QEvent::ApplicationDeactivate)
        {

        }

        else
        {
            return false;
        }
    }

Answer 1

添加事件过滤器以检查激活和停用事件。来自 QEvent 文档：

QEvent::ApplicationActivate 121 应用程序已可供用户使用。
QEvent::ApplicationDeactivate 122 应用程序已挂起，用户无法使用。

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    ui->comboBox->installEventFilter(this);
    .
    .
    .
}

bool MainWindow::eventFilter(QObject *object, QEvent *event)
{
    if (event->type() == QEvent::ApplicationDeactivate)
    {
        // Deactivate timer
    }
    if (event->type() == QEvent::ApplicationActivate)
    {
        // Turn timer back on
    }
    return false;
}

Answer 2

QEvent::AppliciationActivate 和 QEvent::ApplicationDeactivate 已被弃用（请参阅此处）。相反，请使用QEvent::ApplicationStateChange。无需使用事件过滤器即可利用此功能；只需连接到 QGuiApplication::applicationStateChanged(Qt::ApplicationState) 并根据需要进行处理。