Qt中的eventFilter错误

Question

Widget::Widget(QWidget *parent)
: QWidget(parent)
, ui(new Ui::Widget)
{
    ui->setupUi(this);

    installEventFilter(this);
}

bool Widget::eventFilter(QObject *target, QEvent *event)
{
    if(target == this)
    {
        if(event->type() == QEvent::KeyPress)
        {
            QKeyEvent *keyEvent = static_cast<QKeyEvent *>(event);
            if(keyEvent->key()==QT::Key_Space)
            {
                ui->label->setText("ok");
                return true;
            }
            // 마우스 눌린 상태.
        }
    }

    return QWidget::eventFilter(target, event);
}

Error information:

invalid static_cast from type 'QEvent*' to type 'QKeyEvent*'

invalid use of incomplete type 'struct QKeyEvent'

forward declaration of 'struct QKeyEvent'

What I want is :

label setText("ok")  keypress Event 'a' in Form

Answer 1

The error message

invalid use of incomplete type 'struct QKeyEvent'

is a pretty good indicator of the problem. You forgot to #include the header file for QKeyEvent . Add the line

#include <QKeyEvent>

in the file.