Get selected text from current window with C++ \ Qt

Question

I'm trying to get selected text from active window of another app in my Qt application. On Linux I just use QClipboard in Selection mode. On Windows I'm trying to send Ctrl + C to system:

INPUT copyText;
copyText.type = INPUT_KEYBOARD;
copyText.ki.wScan = 0;
copyText.ki.time = 0;
copyText.ki.dwExtraInfo = 0;

Sleep(200);
// Press the "Ctrl" key
copyText.ki.wVk = VK_CONTROL;
copyText.ki.dwFlags = 0; // 0 for key press
SendInput(1, &copyText, sizeof(INPUT));

// Press the "C" key
copyText.ki.wVk = 'C';
copyText.ki.dwFlags = 0; // 0 for key press
SendInput(1, &copyText, sizeof(INPUT));

Sleep(50);

// Release the "C" key
copyText.ki.wVk = 'C';
copyText.ki.dwFlags = KEYEVENTF_KEYUP;
SendInput(1, &copyText, sizeof(INPUT));

// Release the "Ctrl" key
copyText.ki.wVk = VK_CONTROL;
copyText.ki.dwFlags = KEYEVENTF_KEYUP;
SendInput(1, &copyText, sizeof(INPUT));
Sleep(50);

But this hack doesn't work properly - sometimes I don't get selection. I think it can be caused by a hot key that calls function with this code and some keys are still pressed while this code is running. How can I check if every key isn't pressed from QKeySequenceEdit? Or how can I check if no one key pressed? Or is there an easier way to get the selected text from the active window on Windows?

Answer 1

My solution to get selected text:

QString MainWindow::selectedText()
{
    QString selectedText;
#if defined(Q_OS_LINUX)
    selectedText = QApplication::clipboard()->text(QClipboard::Selection);
#elif defined(Q_OS_WIN) // Send Ctrl + C to get selected text
    // Save original clipboard data
    QVariant originalClipboard;
    if (QApplication::clipboard()->mimeData()->hasImage())
        originalClipboard = QApplication::clipboard()->image();
    else
        originalClipboard = QApplication::clipboard()->text();

    // Wait until the hot key is pressed
    while (GetAsyncKeyState(translateSelectedHotkey->currentNativeShortcut().key) || GetAsyncKeyState(VK_CONTROL)
           || GetAsyncKeyState(VK_MENU) || GetAsyncKeyState(VK_SHIFT))
        Sleep(50);

    // Generate key sequence
    INPUT copyText[4];

    // Set the press of the "Ctrl" key
    copyText[0].ki.wVk = VK_CONTROL;
    copyText[0].ki.dwFlags = 0; // 0 for key press
    copyText[0].type = INPUT_KEYBOARD;

    // Set the press of the "C" key
    copyText[1].ki.wVk = 'C';
    copyText[1].ki.dwFlags = 0;
    copyText[1].type = INPUT_KEYBOARD;

    // Set the release of the "C" key
    copyText[2].ki.wVk = 'C';
    copyText[2].ki.dwFlags = KEYEVENTF_KEYUP;
    copyText[2].type = INPUT_KEYBOARD;

    // Set the release of the "Ctrl" key
    copyText[3].ki.wVk = VK_CONTROL;
    copyText[3].ki.dwFlags = KEYEVENTF_KEYUP;
    copyText[3].type = INPUT_KEYBOARD;

    // Send key sequence to system
    SendInput(4, copyText, sizeof(INPUT));

    // Wait for the clipboard to change
    QEventLoop loop;
    QTimer timer; // Add a timer for the case where the text is not selected
    loop.connect(QApplication::clipboard(), &QClipboard::changed, &loop, &QEventLoop::quit);
    loop.connect(&timer, &QTimer::timeout, &loop, &QEventLoop::quit);
    timer.start(1000);
    loop.exec();

    // Translate the text from the clipboard if the selected text was not copied
    if (timer.isActive())
        return QApplication::clipboard()->text();
    else
        timer.stop();

    // Get clipboard data
    selectedText = QApplication::clipboard()->text();

    // Return original clipboard
    if (originalClipboard.type() == QVariant::Image)
        QApplication::clipboard()->setImage(originalClipboard.value<QImage>());
    else
        QApplication::clipboard()->setText(originalClipboard.toString());
#endif
    return selectedText;
}

To set global shortcuts I used QHotkey. From QHotkey I get native keycodes using the currentNativeShortcut().key method.