Running QT application on DEL modules shows NO output in LCD display

A Qt for Embedded Linux application requires a server application to be running, or to be the server application itself. Any Qt for Embedded Linux application can be the server application by constructing the QApplication object with the QApplication::GuiServer type, or by running the application with the -qws command line option.

Below example shows how to run a QT application in command line.
#/usr/bin/qt-embedded/application_name -qws

To run a QT application from Digi ESP , add -qws option in Run Configuration.
Right click on QT project and go to Run As > Run Configurations > C/C++ Remote Application > application_name > Arguments Tab > Add -qws in C/C++ Program Arguments field.

Apply & Run.
QT application will run with GUI in display.

References:-

• http://qt-project.org/doc/qt-4.8/qt-embedded-running.html
• Digi EL Help Docs