title: Qt Catching signal of checkbox to do an action
body: <p>In my Qt program, I want to catch the signal of one of my checkbox to know if it's checked or not. I did it :</p>
  
  <pre><code>#include &lt;iostream&gt;
  #include &lt;QVBoxLayout&gt;
  #include &lt;QtGui&gt;
  #include "Window.h"
  
  Window::Window() : QWidget()
  {
    setFixedSize(400, 800);
  
    m_bouton = new QPushButton("Module 1");
    m_bouton-&gt;setCursor(Qt::PointingHandCursor);
  
    m_bouton2 = new QPushButton("Module 2");
    m_bouton2-&gt;setCursor(Qt::PointingHandCursor);
  
    m_bouton3 = new QPushButton("Module 3");
    m_bouton3-&gt;setCursor(Qt::PointingHandCursor);
  
    m_bouton4 = new QPushButton("Module 4");
    m_bouton4-&gt;setCursor(Qt::PointingHandCursor);
  
    m_check4 = new QCheckBox(this);
    m_check4-&gt;move(300, 50);
    m_check4-&gt;setChecked(true);
  
    m_check3 = new QCheckBox(this);
    m_check3-&gt;move(200, 50);
    m_check3-&gt;setChecked(true);
  
    m_check2 = new QCheckBox(this);
    m_check2-&gt;move(100, 50);
    m_check2-&gt;setChecked(true);
  
    m_check1 = new QCheckBox(this);
    m_check1-&gt;move(0, 50);
    m_check1-&gt;setChecked(true);
  
    QVBoxLayout *layout = new QVBoxLayout;
    layout-&gt;addWidget(m_bouton);
    layout-&gt;addWidget(m_bouton2);
    layout-&gt;addWidget(m_bouton3);
    layout-&gt;addWidget(m_bouton4);
    this-&gt;setLayout(layout);
    this-&gt;setStyleSheet("border: 1px solid black; border-radius: 10px;");
  
    this-&gt;setWindowOpacity(0.5);
    QWidget::setWindowFlags(Qt::Tool | Qt::WindowStaysOnTopHint);
    QWidget::setWindowTitle("Monitor Core");
    QObject::connect(m_bouton4, SIGNAL(clicked()), this, SLOT(SizeCHange()));
    QObject::connect(m_check4, SIGNAL(clicked()), this, SLOT(SizeCHange()));
  }
  
  void    Window::SizeCHange()
  {
    setFixedSize(400, 800 - 200);
    m_bouton4-&gt;setVisible(false);
  }
  </code></pre>
  
  <p>and this is my .h :</p>
  
  <pre><code>#ifndef _WINDOW_H_
  #define _WINDOW_H_
  
  #include &lt;QApplication&gt;
  #include &lt;QWidget&gt;
  #include &lt;QPushButton&gt;
  #include &lt;QCheckBox&gt;
  
  class Window : public QWidget
  {
    Q_OBJECT
  
   public:
    Window();
  
    public slots:
      void SizeCHange();
  
   private:
      QPushButton *m_bouton;
      QPushButton *m_bouton2;
      QPushButton *m_bouton3;
      QPushButton *m_bouton4;
      QCheckBox *m_check1;
      QCheckBox *m_check2;
      QCheckBox *m_check3;
      QCheckBox *m_check4;
  };
  
  #endif
  </code></pre>
  
  <p>This is working but just one time. I want to know if it's check or not, then I will be able to resize my window and make something invisible as I want.</p>