Qt applications behave well in the user's desktop environment, but certain integrations require additional, and sometimes platform specific, techniques.
Various classes in Qt are designed to help developers integrate applications into users' desktop environments. These classes enable developers to take advantage of native services while still using a cross-platform API.
Methods for accessing common desktop services
Access to screen information on multi-head systems
Icon for an application in the system tray
Setting the Application Icon
In order to change the icon of the executable application file itself, as it is presented on the desktop (i.e., prior to application execution), it is necessary to employ another, platform-dependent technique.
Opening External Resources
QDesktopServices provides an interface to services offered by the user's desktop environment. In particular, the openUrl() function is used to open resources using the appropriate application, which may have been specifically configured by the user.
System Tray Icons
Many modern desktop environments feature docks or panels with system trays in which applications can install icons. Applications often use system tray icons to display status information, either by updating the icon itself or by showing information in "balloon messages". Additionally, many applications provide pop-up menus that can be accessed via their system tray icons.
The QSystemTrayIcon class exposes all of the above features via an intuitive Qt-style API that can be used on all desktop platforms.
On systems where the user's desktop is displayed using more than one screen, certain types of applications may need to obtain information about the configuration of the user's workspace to ensure that new windows and dialogs are opened in appropriate locations.
The QDesktopWidget class can be used to monitor the positions of widgets and notify applications about changes to the way the desktop is split over the available screens. This enables applications to implement policies for positioning new windows so that, for example, they do not distract a user who is working on a specific task.