Keyboard issues

_Mark_

Hi,
I'm developing with Qt 5.3, linux host and linux target (buildroot on RPi).
Console application without X (eglfs).

I need to handle keypress events from my Qt5 application.

I don't understand how to use the native eglfs feature to catch the keyboard. Please, could you put me on the right way?
I tried a workaround using getch from ncurses in a separate thread and it works, but only from the same terminal the application is launched from. It's ok, but I can't send key from QtCreator. How to?

Thanks!
Mark

SGaist

Hi,

eglfs is only handles the graphic part, you'll need to use e.g. the evdev plugin for your keyboard. More about this "here":http://doc.qt.io/qt-5/embedded-linux.html

_Mark_

Hi,
I've already read that document but still I cannot get it works.

I export QT_QPA_EVDEV_KEYBOARD_PARAMETERS='grab=1', then I create my CoreApp class upon QCoreApplication. Here I reimplement the virtual bool event(QEvent *e).

But no events are generated while pressing keys on the keyboard.

Surely I'm missing something!

SGaist

Did you specify the exact device to use as a keyboard ?

_Mark_

I think is not necessary because there is only one input device: the keyboard itself.

Anyway I tried to set that env var to '/dev/input/input0;grab=1' with no chance.

SGaist

Did you check whether you have the rights to access that device ?

_Mark_

Yes I did. Currently, I'm running the application as root to avoid any problem related to the rights.

SGaist

Then call your application with QT_DEBUG_PLUGINS=1 set, you'll see if there's something happening with the plugins.

_Mark_

Setting QT_DEBUG_PLUGINS=1 leads to no warnings nor messages. The pressed keys are still sent to the console.

SGaist

Can you show your configuration and the command used to launch your application ?

_Mark_

It's a Raspberry Pi Model B+ running a linux buildroot o.s.:

@

uname -a

Linux rpi 3.12.26 #1 PREEMPT Thu Oct 2 20:45:27 CEST 2014 armv6l GNU/Linux
@

Here the command I use to launch my application:

@
./myapp
@

I also tried:

@
./myapp < /dev/tty1
@

Even with the QT_QPA_EVDEV_KEYBOARD_PARAMETERS variable set, when I hit any key on the keyboard it will show the char on the console, instead of being grabbed by the application. I.e. no QCoreApplication::event() is emitted.

SGaist

What parameters did you set on QT_QPA_EVDEV_KEYBOARD_PARAMETERS ?

_Mark_

As I said in a previous post I tried the following:

@
export QT_QPA_EVDEV_KEYBOARD_PARAMETERS=‘grab=1’
export QT_QPA_EVDEV_KEYBOARD_PARAMETERS=‘/dev/input/input0;grab=1’
@

Anyway the keyboard is the only input device available and also the only USB device connected.

SGaist

Are you running your application through ssh ?

_Mark_

The behavior is the same if either I launch the application through ssh or locally.

Halo_Hao

run：cat /proc/bus/input/devices