QT Animation Simple Pushbutton Help

Hey all,

I'm having difficulties incorporating a simple state machine pushbutton in a widget.

The following code works fine:

Code:

---

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
 
    QPushButton *pushButton1 = new QPushButton();
    QtStateMachine machine;
 
    QtState *s1 = new QtState(machine.rootState());
    s1->assignProperty(pushButton1, "text", "In s1");
 
    QtState *s2 = new QtState(machine.rootState());
    s2->assignProperty(pushButton1, "text", "In s2");
 
    QtState *s3 = new QtState(machine.rootState());
    s3->assignProperty(pushButton1, "text", "In s3");
 
    s1->addTransition(pushButton1, SIGNAL(clicked()), s2);
    s2->addTransition(pushButton1, SIGNAL(clicked()), s3);
    s3->addTransition(pushButton1, SIGNAL(clicked()), s1);
 
    pushButton1->resize(200, 200);
    pushButton1->show();
 
    machine.setInitialState(s1);
    machine.start();
 
    return a.exec();
}

---

But if I declare a widget in a separate file (widget.cpp and widget.h) and call it from main:

Code:

---

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
 
 
    Widget w;
    w.show();
 
    return a.exec();
}

---

Definition within the widget:

Code:

---

Widget::Widget(QWidget *parent)
    : QWidget(parent)
{
    QVBoxLayout *mainLayout = new QVBoxLayout;
    QPushButton *pushButton1 = new QPushButton();
 
    QtStateMachine machine;
 
    QtState *s1 = new QtState(machine.rootState());
    s1->assignProperty(pushButton1, "text", "In s1");
 
    QtState *s2 = new QtState(machine.rootState());
    s2->assignProperty(pushButton1, "text", "In s2");
 
    QtState *s3 = new QtState(machine.rootState());
    s3->assignProperty(pushButton1, "text", "In s3");
 
    s1->addTransition(pushButton1, SIGNAL(clicked()), s2);
    s2->addTransition(pushButton1, SIGNAL(clicked()), s3);
    s3->addTransition(pushButton1, SIGNAL(clicked()), s1);
 
    machine.setInitialState(s1);
    machine.start();
 
    mainLayout->addWidget(pushButton1);
    setLayout(mainLayout);
}

---

The button appears but no text appears. i.e. the state machine doesn't seem to work.

Any help would be deeply appreciate, Thanks.

Regards,
Pembar

Hi, that's a easy c++ issue. *s1 is deleted after the Widget::Widget scope is leaved. Define the states as member variables of the class and it will work.

Code:

---

class Widget
{
//...
  private:
    QtState *s1;
}
Widget::Widget()
{
  //...
  s1 = new QtState(machine.rootState());
}

---

The QtStateMachine are destoyed when Widget COnstructor return;

You must dinamically allocate it.

Code:

---

QtStateMachine* machine = new QtStateMachine(this);

---

Quote:

---

Originally Posted by mcosta

The QtStateMachine are destoyed when Widget COnstructor return;

---

Ah, even better:o

God I love you guys.... Thanks much.

Regards,
Pembar