I'm trying to create a custom tab control - A widget with QToolButtons laid in QVBoxLayout and an QStackedLayout placed adjacently. Here my QToolButtons are in contained in QList.
I've written a function called addTab(...) which adds buttons to the vertical layout dynamically and also the widget to be show to stacked layout.

My Question:
Signal mapper object's connect statement is written even before the mapping is done. So is this the reason the button click is not emitting signal ?
Qt Code: 
  1. // ctabwidget.cpp
  2. #include "ctabwidget.h"
  3. #include <QHBoxLayout>
  4. #include <QVBoxLayout>
  5. #include <QToolButton>
  6. #include <QStackedLayout>
  7. #include <QDebug>
  8. #include <QSignalMapper>
  9.  
  10. CTabWidget::CTabWidget(QWidget *parent) :
  11.     QWidget(parent)
  12. {
  13.     mainLayout = new QHBoxLayout;
  14.     mainLayout->setSpacing(0);
  15.     mainLayout->setContentsMargins(0, 0, 0, 0);
  16.     this->setLayout(mainLayout);
  17.  
  18.     buttonLayout = new QVBoxLayout;
  19.     buttonLayout->setSpacing(0);
  20.  
  21.     stackLayout = new QStackedLayout;
  22.     stackLayout->setContentsMargins(0, 0, 0, 0);
  23.     stackLayout->setSpacing(0);
  24.  
  25.     mainLayout->addLayout(buttonLayout);
  26.     mainLayout->addLayout(stackLayout);
  27.  
  28.     signalMapper = new QSignalMapper;
  29.     connect(signalMapper, SIGNAL(mapped(int)), this, SLOT(selectTab(int)));
  30. }
  31.  
  32. CTabWidget::~CTabWidget()
  33. {
  34.     qDeleteAll(tabButtons);
  35. }
  36.  
  37. // This will be called after the constructor is executed
  38. // Is this the reason why signals aren't emitted on button click ??
  39. void CTabWidget::addTab(const QString & normalIcon, const QString & hoverIcon, const QString & selectIcon, QWidget * tabWidget)
  40. {
  41.     tabButtons.append(new CTabButton());
  42.     CTabButton * tabButton = tabButtons.last();
  43.     tabButton->setFixedSize(196, 54);
  44.     tabButton->setCheckable(true);
  45.     tabButton->setFocusPolicy(Qt::NoFocus);
  46.     tabButton->setStyleSheet("QToolButton { border-image: url(" + normalIcon + "); border: none; border-top-left-radius: 2px; border-bottom-left-radius: 2px; background-color: transparent; }"
  47.                              "QToolButton:hover { border-image: url(" + hoverIcon + "); border: none;  }"
  48.                              "QToolButton:checked { border-image: url(" + selectIcon + "); border: none; }");
  49.     buttonLayout->addWidget(tabButton);
  50.     stackLayout->addWidget(tabWidget);
  51.     connect(tabButton, SIGNAL(clicked()), signalMapper, SLOT(map()));
  52.     int buttonId = tabButtons.size();
  53.     signalMapper->setMapping(tabButton, buttonId);
  54.     qDebug() << buttonId;
  55. }
  56.  
  57. void CTabWidget::doneAddingTabs(void)
  58. {
  59.     buttonLayout->addStretch();
  60. }
  61.  
  62. // slot
  63. void CTabWidget::selectTab(int tabId)
  64. {
  65.     tabId = tabId - 1;
  66.     qDebug() << "Tab Id - " << tabId;
  67.     if(tabId < 0)
  68.         return;
  69.  
  70.     stackLayout->setCurrentIndex(tabId);
  71. }
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Qt Code: 
  1. // main.cpp
  2. #include "ctabwidget.h"
  3. #include <QApplication>
  4. #include <QLabel>
  5. #include <QList>
  6.  
  7. int main(int argc, char *argv[])
  8. {
  9.     QApplication a(argc, argv);
  10.  
  11.     QList<QLabel *> labels;
  12.  
  13.     for(int i = 0; i < 4; i++)
  14.     {
  15.         labels.append(new QLabel(QString::number(i+1)));
  16.     }
  17.  
  18.     CTabWidget w;
  19.     w.addTab(":/tabIcons/idbak.png", ":/tabIcons/idbak_sel.png", ":/tabIcons/idbak_sel.png", labels.at(0));
  20.     w.addTab(":/tabIcons/idrst.png", ":/tabIcons/idrst_sel.png", ":/tabIcons/idrst_sel.png", labels.at(1));
  21.     w.addTab(":/tabIcons/idsch.png", ":/tabIcons/idsch_sel.png", ":/tabIcons/idsch_sel.png", labels.at(2));
  22.     w.addTab(":/tabIcons/idlog.png", ":/tabIcons/idlog_sel.png", ":/tabIcons/idlog_sel.png", labels.at(3));
  23.     w.doneAddingTabs();
  24.     w.show();
  25.  
  26.     return a.exec();
  27. }
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Thank you.