How to emit a signal from a QPushButton when the mouse hovers over it?

Question

Recently, I wanted that QPushButton can emit a signal, when the mouse pointer enters. How can I make it?

I know that QPushButton has some already defined signal, such as clicked(), pressed(), destory() and so on. But no signal like hover(), enter(), ...

I looked some information about it: Someone said it can be done by css. I don't understand. Can you give me some advice ? Thank you!

Answer 1

You can use QWidget::enterEvent ( QEvent * event ) for this.

You override this event and send a custom defined signal when ever this event occurs.

First you have to enable mouse tracking for this widget (setMouseTracking(true) in the constructor for example).

Header file:

class my_button
{
    // ...

protected:
    virtual void enterEvent( QEvent* e );

public Q_SIGNALS:
    void hovered();

    // ...
};

Source file:

void my_button::enterEvent( QEvent* e )
{
    Q_EMIT hovered();

    // don't forget to forward the event
    QWidget::enterEvent( e );
}

Where you use your button:

connect( one_of_my_button, SIGNAL(hovered()), this, SLOT(do_something_when_button_hovered()) );