qt - How to resize buttons automatically if the window changes its size? -

i have window , bunch of push buttons. window "main menu". after placing buttons, have these buttons fixed size of window. should fill window , change size if window changes (by user instance).

how do that?

you should use layouts. according documentation,

the qt layout system provides simple , powerful way of automatically arranging child widgets within widget ensure make use of available space.

example:

main.cpp

#include "widget.h" #include <qapplication>  int main(int argc, char *argv[]) {     qapplication a(argc, argv);     widget w;     w.show();      return a.exec(); } 

widget.h

#ifndef widget_h #define widget_h  #include <qwidget>  class widget : public qwidget {     q_object  public:     explicit widget(qwidget *parent = 0);     ~widget();  private:  }; 

widget.cpp

#include "widget.h" #include <qpushbutton> #include <qhboxlayout>  widget::widget(qwidget *parent) :     qwidget(parent) {     qpushbutton *button1 = new qpushbutton("one");     qpushbutton *button2 = new qpushbutton("two");      //horizontal layout 2 buttons     qhboxlayout *hblayout = new qhboxlayout;     hblayout->addwidget(button1);     hblayout->addwidget(button2);      qpushbutton *button3 = new qpushbutton("three");     qpushbutton *button4 = new qpushbutton("four");      //vertical layout 2 buttons     qvboxlayout *vblayout = new qvboxlayout;     vblayout->addwidget(button3);     vblayout->addwidget(button4);      //we add our 2 layouts (horizontal & vertical)     //following vertical layout.     qvboxlayout *mainlayout = new qvboxlayout;     mainlayout->addlayout(hblayout);     mainlayout->addlayout(vblayout);      this->setlayout(mainlayout); }  widget::~widget() {  }