For those coming here from google like me, searching for a QML/QtQuick solution, because they are using the ApplicationWindow
Item, I add this answer.
Simply set the maximum height/width to the minimum height/width:
ApplicationWindow {
visible: true
maximumHeight: minimumHeight
maximumWidth: minimumWidth
[...]
}
Please note that you should not deactivate the window resizing if there are other possibilities (like resizing the content). The users don't like unresizable windows. For instance, in my case, I only locked the height - because I had the possibility to resize some elements in their width: My QML Slider uses as much space as there is available thanks to QtQuick Layouts. However, resizing a few Buttons and a slider in their height would not make sense. TableViews, TextFields etc., however, are predestinated for being resized.