Question

I am a newbie to Qt and facing issue in my application. So here is what I am trying to do.

I have a class with QWidget as parent. This class has a grid layout on it. I set this widget as a central widget to main window. (this thing worked fine though this widget is not centered on Main Window.)

Now I wanted to rotate this widget in 90 degrees so that it can bee shown on device in landscape mode. So I created a graphics view and added this widget to it. (created a scene added widget to that and assigned scene to view.) then this graphics view was rotated and made central widget. this worked amazingly and it was very well centered, looked good on device as well.

But in final integration we want to have all QWidgets so Graphics View is not an option. To tackle this I created a Qwidget member inside my class. applied the layout to it. added this widget to graphicsView and my class was made parent to it.

This also works but has the similar issue I faced in first step, it sits in the top left corner of MainWindow and does not adjust to center. To make things even worse, when deployed on device it was not applied to entire screen. Widget was sitting in some part of top left area and had scroll bars to it! I even tried the set Window State to maximized but had no effect on it.

Here is what I tried

The widget is created inside my class and been added to Graphics View. this view has my class as parent and it will be rotated by using rotate api.

m_gridContainer = new QWidget();
m_gridContainer->setAutoFillBackground(true);
m_gridContainer->setPalette(blackPalette);
m_gridContainer->setLayout(m_grid);
m_gridContainer->setMinimumSize(480,265);

m_scene = new QGraphicsScene(0, 0, 480, 265);
m_window = new QGraphicsView(m_scene,this);
m_scene->setBackgroundBrush(brush);
m_window->setAlignment(Qt::AlignCenter);    
m_scene->addWidget(m_gridContainer,Qt::Widget);

To use it from main Window

m_window = new CMyWidget(label, m_txtBox->text());    
m_window->getRotatedWidget(90);
setCentralWidget(m_window);

I tried whatever I can but this widget is not being shown full screen (in just a small area) and still have scroll bars to it. I have no idea what exactly is happening there.

Answer 1

m_gridContainer being a graphics item part of a graphics scene, it doesn’t receive the resize events of you main window.

You have to handle the resizeEvent() on your CMyWidget and adjust the size of your m_gridContainer accordingly, e.g.

void CMyWidget::resizeEvent ( QResizeEvent * event )
{
    m_gridContainer->resize(event->size());
}

BTW, if you are handling the rotation for use on a mobile device, it is managed by Qt itself (by simply resizing your main window). You don’t have to do it in your code (you’ll actually end up with a widget looking like it has been rotated twice).