Please make sure you use the latest image, if not please follow Upgrade The System to upgrade your system.

Install QT5 packages.

sudo apt update
sudo apt install qt5-default qtbase5-examples
mkdir /tmp/qt5
cd /tmp/qt5
wget https://dl.khadas.com/repos/debs/vim3/focal/qt5/libqt5gui5_5.12.8%2Bdfsg-0ubuntu2_arm64.deb
sudo dpkg -i libqt5gui5_5.12.8+dfsg-0ubuntu2_arm64.deb

Switch to Framebuffer mode.For desktop image, you can use Ctrl+Alt+F1 to switch to framebuffer console mode.

Setup the environment variables below.

export QT_QPA_PLATFORM=eglfs
export QT_QPA_EGLFS_INTEGRATION=eglfs_mali

Run test:

/usr/lib/aarch64-linux-gnu/qt5/examples/opengl/qopenglwidget/qopenglwidget

If every thing works you will see the QT demo running on screen.

If you want to run the QT demo on TS050 touchscreen you need to remove the HDMI cable first.

The TS050 touchscreen is portrait mode by default, if you want to use the QT under landscape mode you need to setup the environment variables below to rotate the screen and touchscreen:

export QT_QPA_EGLFS_ROTATION=90
export QT_QPA_EGLFS_DISABLE_INPUT=1
export QT_QPA_EVDEV_TOUCHSCREEN_PARAMETERS=/dev/input/event3:rotate=90
export QT_QPA_GENERIC_PLUGINS=evdevtouch:/dev/input/event3

export QT_QPA_EGLFS_ROTATION=90
export QT_QPA_EGLFS_DISABLE_INPUT=1
export QT_QPA_EVDEV_TOUCHSCREEN_PARAMETERS=/dev/input/event4:rotate=90
export QT_QPA_GENERIC_PLUGINS=evdevtouch:/dev/input/event4

For other orientation rotation, you can change them yourself.

When you install such version of library you will break some packages (such as qtcreator) which depend on the original library, if you don’t want to break the packages you can follow the instructions below to install the original QT5 library.

wget http://ports.ubuntu.com/pool/universe/q/qtbase-opensource-src/libqt5gui5_5.12.8+dfsg-0ubuntu1_arm64.deb
sudo dpkg -i libqt5gui5_5.12.8+dfsg-0ubuntu1_arm64.deb

Qt for Embedded Linux