Two-way Button Example

The Two-way button example shows how to use Qt State Machine Framework to implement a simple state machine that toggles the current state when a button is clicked.

Article lu fois.

L'auteur

The Qt Company Ltd.

L'article

Publié le 27 décembre 2024 - Mis à jour le 27 décembre 2024

Liens sociaux

Two-way Button Example▲

Sélectionnez

int main(int argc, char **argv)
{
    QApplication app(argc, argv);
    QPushButton button;
    QStateMachine machine;

The application's main() function begins by constructing the application object, a button and a state machine.

Sélectionnez

    QState *off = new QState();
    off-&gt;assignProperty(&amp;button, "text", "Off");
    off-&gt;setObjectName("off");

    QState *on = new QState();
    on-&gt;setObjectName("on");
    on-&gt;assignProperty(&amp;button, "text", "On");

The state machine has two states; on and off. When either state is entered, the text of the button will be set accordingly.

Sélectionnez

    off-&gt;addTransition(&amp;button, &amp;QAbstractButton::clicked, on);
    on-&gt;addTransition(&amp;button, &amp;QAbstractButton::clicked, off);

When the state machine is in the off state and the button is clicked, it will transition to the on state; when the state machine is in the on state and the button is clicked, it will transition to the off state.

Sélectionnez

    machine.addState(off);
    machine.addState(on);

The states are added to the state machine; they become top-level (sibling) states.

Sélectionnez

    machine.setInitialState(off);
    machine.start();

The initial state is off; this is the state the state machine will immediately transition to once the state machine is started.

Sélectionnez

    button.resize(100, 50);
    button.show();
    return app.exec();
}

Finally, the button is resized and made visible, and the application event loop is entered.

Example project▲

Example project @ code.qt.io

Vous avez aimé ce tutoriel ? Alors partagez-le en cliquant sur les boutons suivants :