Keep created object alive. How?

bogong

Hello all!
I am running static function from one class that should create some objects and attach it to main function. How to do it in Qt?

main.cpp

int main(int Counter, char *Arguments[]) {

	QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
	CustomApplication Application(Counter,Arguments);

	QQmlApplicationEngine Engine;

	>>>> CustomClass::staticFunction(&Engine)

	Engine.load(QUrl(Main));
	if (Engine.rootObjects().isEmpty())
		return -1;

	return Application.exec();

customclass.cpp

void CustomClass::staticFunction(QQmlApplicationEngine &Engine) {

	QQmlContext *Context = Engine.rootContext();

	Settings appSettings;
	Context->setContextProperty("Settings",&appSettings);
}

In this example object appSettings should be alive in main function scope after finishing of execution of this static function. Beside this the list of objects might be bigger.

VRonin

Allocate on the heap and give ownership of the memory to something else (Engine?)

Settings* appSettings = new Settings;
QObject::connect(&Engine,&QObject::destroyed,[appSettings](){delete appSettings;});
Context->setContextProperty("Settings",appSettings);

Christian Ehrlicher

Or simply let Settings derive from QObject and pass Engine as parent so it will automatically destroyed when Engine is deleted.

bogong

@VRonin Engine is object that is conaining context. I need to hold Settings standalone in main, but be contexted to Engine. Global idea - create standalone objects from static function, keep them alive when function finished and hold them in context of Engine.

Thanks for reply. I am always trying to avoid HEAP. In this case it's might be better to use kind of object-wrapper and in constructor of it do everything I need and keep it alive in main by direct implementation.

bogong

@Christian-Ehrlicher Will try to do it in hour. But the global idea was to develop them like standalone object but inside of main.

bogong

Decided do not making additional complexity. The solution is - do not do anything additional and use plain objects definition inside of "main" function.

Qt Project example published in Github

main.cpp

int main(int Counter, char *Arguments[]) {

	QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
	CuxtomApplication Application(Counter,Arguments);

	QQmlApplicationEngine Engine;
	QQmlContext *Context = Engine.rootContext();

	AppSettings Settings;
	Context->setContextProperty("Settings",&Settings);

	Engine.load(QUrl(Main));
	if (Engine.rootObjects().isEmpty())
		return -1;

	return Application.exec();
}