Display buttons in the middle of the screen in BlackBerry 10 app using qt c++

Question

I wanted a screen in my application which should look like this:

This means the button in the screen should appear in the centre for screen both horizontally and vertically.

Does anyone how to do it. I have written the following code but its not working.

Container *contentContainer = new Container();
contentContainer->setLayout(StackLayout::create());  
//contentContainer->setVerticalAlignment(VerticalAlignment::Center);
contentContainer->setHorizontalAlignment(HorizontalAlignment::Center);

Button* submitButton =  new Button();
submitButton->setText("Submit");

Button* cancelButton =  new Button();
cancelButton->setText("Cancel");

contentContainer->add(submitButton);
contentContainer->add(cancelButton);

Page * testPage = new Page();
testPage ->setContent(contentContainer);

Sheet *testSheet = new Sheet();
testSheet->setContent( LoginSheetPage );

testSheet->open();

Answer 1

To get it center , First you have to create container with docklayout() and inside this container, you have to create stacklayout() with buttons and set docklayout() container as a content of Page.

Container *contentContainer = new Container();
contentContainer->setLayout(StackLayout::create());  
contentContainer->setVerticalAlignment(VerticalAlignment::Center);
contentContainer->setHorizontalAlignment(HorizontalAlignment::Center);

Button* submitButton =  new Button();
submitButton->setText("Submit");

Button* cancelButton =  new Button();
cancelButton->setText("Cancel");

contentContainer->add(submitButton);
contentContainer->add(cancelButton);

Container *rootContainer = new Container();
rootContainer->setLayout(DockLayout::create());  
rootContainer->setVerticalAlignment(VerticalAlignment::Fill);
rootContainer->setHorizontalAlignment(HorizontalAlignment::Fill);
rootContainer->add(contentContainer);

Page * testPage = new Page();
testPage ->setContent(rootContainer);