How to detect hot-key release event, when using QxtGlobalShortcut ?

Soul

My application is as below:
1>When the hot key is pressed , then the application start to record voice.
2>When the hot key is released, then the application stop record the voice.

Note : The application may not have the focus.

I have tried the QxtGlobalShortcut class, but it seems no "signal" when the hot key released.

The code is below:

QxtGlobalShortcut *shortcut = new QxtGlobalShortcut();
    if(shortcut->setShortcut(QKeySequence("Shift+1"))){
        qDebug("Create short cut done\r\n");
    }
    else{
        qDebug("Create short cut failed\r\n");
    }
    QObject::connect(shortcut, SIGNAL(activated()),
                     this, SLOT(onInputKeyPressed()));
    shortcut->setEnabled();

Is there any good idea ? Thanks in advance !

Soul

I found an appearance the hot-key event always occurres when I hold the key.
Is this a good way which to create a timer to detect the key release ?

mrjj

@Soul
Hi what platform do u need this on ?

Soul

Hi @mrjj , I just run it on windows.

mrjj

@Soul
hi
Ok. so not an issue if not crossplatform ?

You can use RegisterHotkey to detect the key going down, then use polling (with timer) with GetAsyncKeyState
to see it goes up. I did not find any way to use WM_HOTKEY and get event on
button released. It was suggested to use DLL with SetWindowsHookEx()
but it seems like much work for 1 hotkey.

The RegisterHotkey is pretty trivial
http://amin-ahmadi.com/2015/11/14/how-to-use-system-wide-hotkeys-in-your-qt-application/
note the LIBS += -lUser32

and GetAsyncKeyState should be not be hard either.
https://msdn.microsoft.com/en-us/library/windows/desktop/ms646293(v=vs.85).aspx

Soul

@mrjj
Hi , thank you for your reply . I think GetAsyncKeyState is the best solution for me.
By the way, If I want to make it corssplatform, what shall I do ? Could I have your suggestion ?

mrjj

@Soul
Hi
I never found a linux version that could tell when key released.
Those i tested only gave Activated() signal.

https://github.com/mitei/qglobalshortcut

Im sure its possible with native linux programming but i never looked more into it.