Touch input not accepted in Windows 8 if QtQuick2ApplicationViewer is subclassed

jech

Hi,

I wrote a QML/C++ program. Now I purchased a Windows 8.1 tablet and if I run the application, it won't respond to any touch o gesture. I found out that the problem is caused by a small portion of code in which I subclassed QtQuick2ApplicationViewer. The code looks like this:

@class Window : public QtQuick2ApplicationViewer
{
QmltoCpp* qmltocpp;

public:
void setQmlClass(QmltoCpp* &qmlClass) {
qmltocpp = qmlClass;
}

protected:
bool event(QEvent *e) Q_DECL_OVERRIDE
{
int type = e->type();
if (type == QEvent::Close) {
qmltocpp->exit();
}
return QWindow::event(e);
}
};

int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);
Window viewer;
viewer.setMainQmlFile(QStringLiteral("qml/MyApp/main.qml"));
viewer.showExpanded();
return app.exec();
}
@

I subclassed the QtQuick2ApplicationViewer to be able to catch application close event and save settings to a database.

If I just replace the line
@Window viewer;@
by
@QtQuick2ApplicationViewer viewer;@
it works as expected except my settings are not saved of course.

Is there anything wrong in my code which would explain this behavior? Is there any other way how I can catch and delay application exit?

SGaist

Hi,

@
bool event(QEvent *e) Q_DECL_OVERRIDE
{
int type = e->type();
if (type == QEvent::Close) {
qmltocpp->exit();
}
return QWindow::event(e); << it's not the base class implementation
}@

jech

Hi,
thanks a lot for the tip.

I found the code I'm using here: http://answer.techwikihow.com/297416/ask-confirmation-before-closing-qquickview-qapplication.html

I now tried another approach and installed an eventFilter which filters QEvent::Close. The code now looks like this:

@class Window : public QtQuick2ApplicationViewer
{
QmltoCpp* qmltocpp;

public:
void setQmlClass(QmltoCpp* &qmlClass) {
qmltocpp = qmlClass;
}

protected:
bool eventFilter(QObject *obj, QEvent *ev) {
if (ev->type() == QEvent::Close) {
qmltocpp->exit();
return true;
} else {
return false;
}
}
};

int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);
Window viewer;
viewer.installEventFilter(&viewer);
viewer.setMainQmlFile(QStringLiteral("qml/MyApp/main.qml"));
viewer.showExpanded();
return app.exec();
}
@

The function qmltocpp->exit() writes the settings to database and then closes the app by calling
@QGuiApplication::quit();@

It works as before on Windows 7, tomorrow I'll try it on my Windows 8 tablet. I hope it will work now.