Need help to code VirtualKeyboard using QQuickWidget on Widget-based app

[IMAN4K]

@raven-worx said

yes, if you want to use it with QtWidgets.
An InputPanel QML element can also show a virtualkeyboard using EGLFS.

So far so good!
I have managed to cross compile Qt v5.12.3 on Raspbian stretch@Raspberry Pi3B+ without EGLFS and with EGL on X11 and all Virtual Keyboard plugins are deployed correctly based on Deployment Guide BUT VK won't run and if we set QT_DEBUG_PLUGINS to true only $$[QT_INSTALL_PLUGINS]/platforminputcontexts/libqtvirtualkeyboardplugin.so is loaded(full log).
So do you have any clue about what's wrong?
Regards.

Hope to get to a solution on this topic for anyone else

[raven-worx]

@iman4k
did you set QT_IM_MODULE=qtvirtualkeyboard env variable?
How do you start your application? With what parameters and or platform plugin?
Do you see your application in your X11 display?

[IMAN4K]

@raven-worx said in Need help to code VirtualKeyboard using QQuickWidget on Widget-based app:

@iman4k
did you set QT_IM_MODULE=qtvirtualkeyboard env variable?
How do you start your application? With what parameters and or platform plugin?
Do you see your application in your X11 display?

• Yes, before QApplication creation in the main function:
  • qputenv("QT_IM_MODULE", QByteArray("qtvirtualkeyboard"));
• ./<my-app> -platform xcb
• Not sure about seeing application on X11 display but yes my app running normally(windowed) just like the desktop-x86 one.

[IMAN4K]

@raven-worx

Also for more debugging when I set qputenv("QT_LOGGING_RULES", QByteArray("qt.virtualkeyboard=true"));, the VK's logs
for raspberry is like this :

qt.virtualkeyboard: Loading extension "japanese"
qt.virtualkeyboard: Loading extension "traditional_chinese"
qt.virtualkeyboard: Loading extension "pinyin"
qt.virtualkeyboard: Loading extension "thai"
qt.virtualkeyboard: Loading extension "hangul"
qt.virtualkeyboard: PlatformInputContext::setFocusObject(): QLineEdit(0x7ec96790)
qt.virtualkeyboard: PlatformInputContext::update(): QFlags<Qt::InputMethodQuery>(ImQueryAll)
qt.virtualkeyboard: PlatformInputContext::update(): QFlags<Qt::InputMethodQuery>(ImInputItemClipRectangle)
qt.virtualkeyboard: PlatformInputContext::setFocusObject(): QLineEdit(0x7ec96790)
qt.virtualkeyboard: PlatformInputContext::update(): QFlags<Qt::InputMethodQuery>(ImQueryAll)
qt.virtualkeyboard: PlatformInputContext::update(): QFlags<Qt::InputMethodQuery>(ImQueryAll)
qt.virtualkeyboard: PlatformInputContext::update(): QFlags<Qt::InputMethodQuery>(ImQueryAll)
qt.virtualkeyboard: PlatformInputContext::update(): QFlags<Qt::InputMethodQuery>(ImQueryAll)
qt.virtualkeyboard: PlatformInputContext::showInputPanel()
qt.virtualkeyboard: PlatformInputContext::commit()
qt.virtualkeyboard: PlatformInputContext::commit()
qt.virtualkeyboard: PlatformInputContext::hideInputPanel()
qt.virtualkeyboard: PlatformInputContext::setFocusObject(): QObject(0x0)
qt.virtualkeyboard: PlatformInputContext::update(): QFlags<Qt::InputMethodQuery>(ImQueryAll)

So showInputPanel() is called but actually is not shown! and couldn't find the reason.
And these logs are for running on Desktop:

qt.virtualkeyboard: PlatformInputContext::update(): QFlags<Qt::InputMethodQuery>(ImInputItemClipRectangle)
qt.virtualkeyboard: PlatformInputContext::setFocusObject(): QLineEdit(0x7ffe8952fa60)
qt.virtualkeyboard: PlatformInputContext::update(): QFlags<Qt::InputMethodQuery>(ImQueryAll)
qt.virtualkeyboard: InputContext::setFocus(): true
qt.virtualkeyboard: PlatformInputContext::setFocusObject(): QLineEdit(0x7ffe8952fa60)
qt.virtualkeyboard: PlatformInputContext::update(): QFlags<Qt::InputMethodQuery>(ImQueryAll)
qt.virtualkeyboard: InputContext::setLocale(): "en_GB"
qt.virtualkeyboard: PlatformInputContext::setLocale(): QLocale(English, Latin, UnitedKingdom)
qt.virtualkeyboard: InputEngine::setInputMethod(): QtVirtualKeyboard::PlainInputMethod(0x1110b60)
qt.virtualkeyboard: InputEngine::setInputMode(): 0
qt.virtualkeyboard: PlatformInputContext::update(): QFlags<Qt::InputMethodQuery>(ImQueryAll)
qt.virtualkeyboard: PlatformInputContext::showInputPanel()
qt.virtualkeyboard: DesktopInputPanel::repositionView(): QRect(55,24 1865x1056)
qt.virtualkeyboard: PlatformInputContext::hideInputPanel()
qt.virtualkeyboard: PlatformInputContext::commit()
qt.virtualkeyboard: PlatformInputContext::commit()
qt.virtualkeyboard: PlatformInputContext::setFocusObject(): QObject(0x0)
qt.virtualkeyboard: PlatformInputContext::update(): QFlags<Qt::InputMethodQuery>(ImQueryAll)
qt.virtualkeyboard: InputContext::setFocus(): false
qt.virtualkeyboard: PlatformInputContext::update(): QFlags<Qt::InputMethodQuery>(ImInputItemClipRectangle)
qt.virtualkeyboard: PlatformInputContext::setFocusObject(): QLineEdit(0x7ffe8952fa60)
qt.virtualkeyboard: PlatformInputContext::update(): QFlags<Qt::InputMethodQuery>(ImQueryAll)
qt.virtualkeyboard: InputContext::setFocus(): true
qt.virtualkeyboard: PlatformInputContext::setFocusObject(): QLineEdit(0x7ffe8952fa60)
qt.virtualkeyboard: PlatformInputContext::update(): QFlags<Qt::InputMethodQuery>(ImQueryAll)
qt.virtualkeyboard: PlatformInputContext::commit()
qt.virtualkeyboard: PlatformInputContext::commit()
qt.virtualkeyboard: InputContext::setFocus(): false

[IMAN4K]

@raven-worx
Any idea or hint would be appreciated.
Regards.

[raven-worx]

@iman4k
seems you somehow loosing input-focus in your non-working case?
are you running the exact same application on desktop and on your pi?
any other output in the console?

[IMAN4K]

@raven-worx said in Need help to code VirtualKeyboard using QQuickWidget on Widget-based app:

@iman4k
seems you somehow loosing input-focus in your non-working case?
are you running the exact same application on desktop and on your pi?
any other output in the console?

• No, input focus is just fine and the lineedit will get focus as expected(the last 3 line of logs in the non-working case is because I clicked on the outside of widget area at the end)
• Yes, the exact same application is running on Desktop and also on Embedded(raspberry) kit
• Nothing more than those logs I mentioned!

This is somehow strange, it took 1 week struggling on this :(

[raven-worx]

@iman4k
then i guess either something in your application or your used Qt installation.
Just to amke sure: I assume - becasue of the log output - the qtvirtualkeyboard plugin is available on your Pi?
are you also using QML in your application or is it a pure QtWidget application?

[IMAN4K]

@raven-worx said in Need help to code VirtualKeyboard using QQuickWidget on Widget-based app:

@iman4k
then i guess either something in your application or your used Qt installation.
Just to amke sure: I assume - becasue of the log output - the qtvirtualkeyboard plugin is available on your Pi?
are you also using QML in your application or is it a pure QtWidget application?

• Yes, these are deployed on the pi side in install step of cross-compile:

  • /usr/local/qt5pi/plugins/platforminputcontexts/libqtvirtualkeyboardplugin.so
  • /usr/local/qt5pi/qml/QtQuick/VirtualKeyboard/libqtquickvirtualkeyboardplugin.so
  • /usr/local/qt5pi/qml/QtQuick/Layouts/libqquicklayoutsplugin.so
  • /usr/local/qt5pi/lib/libQt5VirtualKeyboard.so

  So I assume the plugin is available.

• It's a simple QtWidgets application:

#include <QtWidgets>

int main(int argc, char *argv[]) {
    qputenv("QT_IM_MODULE", QByteArray("qtvirtualkeyboard"));
    qputenv("QT_LOGGING_RULES", QByteArray("qt.virtualkeyboard=true"));
    QApplication a(argc, argv);
    QMainWindow w;
    QLineEdit edit(&w);
    edit.move(50, 50);
    w.show();
    return a.exec();
}

Is this problem related to Openbox WindowManager?
I'm also curious to know why DesktopInputPanel::repositionView(): QRect(55,24 1865x1056) is not called after PlatformInputContext::showInputPanel() in raspberry?

[MarKus12]

@IMAN4K

Hi,
similar problem exists here.
Did you eventually found a solution for the problem, that you remember?

I run into it on a buildroot issue without desktop manager.
Currently I suspect a problem with the interpreting system input events by QApplication.
Seems that QGuiApplication does something different.