如何在QT中获取后台应用程序窗口标题？

Question

In my qt application when I press a button, I need to display the background application window title. Currently i used to manage this in such a way that, call 'getBackgroundWindowTitle' function before 'setupUi' call. So this returns the background application window title for me. My current implementation is as below

MyWindow::MyWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MyWindow)
{
    g_window_title = getBackgroundWindowTitle();
    ui->setupUi(this);
}

void MyWindow::OnPushbuttonPressed()
{
    ui->labelBackgroundWindowTitle.setText(g_window_title);
}

QString MyWindow::getBackgroundWindowTitle()
{
    char buff[256];
    HWND hwnd = GetForegroundWindow(); //currently this gives my current application window title
    GetWindowText(hwnd, (LPWSTR) buff, 254);
    QString title = QString::fromWCharArray((const wchar_t *)buff);
    return title;
}

But, the issue with this code is, when the background application window changes, I need to restart the application to get the background title again because 'getBackgroundWindowTitle' need to be called before setupUi call.

I am looking for anytime solution in such a way that when user pressed the pushbutton, the background application window title should be retrieved.

Can somebody help me to modify my code ?

Answer 1

If it's the previous (or next, see link) window in the Z-Order, you can use: GetNextWindow , like so:

QString MyWindow::getBackgroundWindowTitle()
{
    char buff[256];
    HWND myHwnd = GetForegroundWindow();
    HWND hwnd = GetNextWindow(myHwnd, GW_HWNDNEXT);
    GetWindowText(hwnd, (LPWSTR) buff, 254);
    QString title = QString::fromWCharArray((const wchar_t *)buff);
    return title;
}

Now, if I understand your question, you just need to move the call to getBackgroundWindowTitle to your button handler:

void MyWindow::OnPushbuttonPressed()
{
    ui->labelBackgroundWindowTitle.setText(getBackgroundWindowTitle());
}