When writing in the Textfield, I need my textfield to move upwards in order to let the textfield be visible when the keyboard pops up.
Does libgdx have some kind of
Try
Gdx.input.isPeripheralAvailable(Input.Peripheral.OnscreenKeyboard);
I just looked this up in the docs, don't know if it actually does the trick. But the
Gdx.input.setOnscreenKeyboardVisible(boolean visible);
method could be used as well (like this YOU define when the keyboard is visible and when not).