TabStackedWidget: Only send show event to one widget after removing tab

When removing current tab, the widget was removed from stackwidget,
which would send the show event to next widget in stack and then
send show event to another widget when changing the current index from
ComboTabBar.

src/lib/tabwidget/tabstackedwidget.cpp

@@ -32,6 +32,8 @@ TabStackedWidget::TabStackedWidget(QWidget* parent)
     : QWidget(parent)
     , m_stack(0)
     , m_tabBar(0)
+    , m_currentIndex(-1)
+    , m_previousIndex(-1)
 {
     m_stack = new QStackedWidget(this);
     m_mainLayout = new QVBoxLayout;
@@ -92,6 +94,16 @@ void TabStackedWidget::tabWasMoved(int from, int to)
 
 void TabStackedWidget::tabWasRemoved(int index)
 {
+    if (m_previousIndex == index)
+        m_previousIndex = -1;
+    else if (m_previousIndex > index)
+        --m_previousIndex;
+
+    if (m_currentIndex == index)
+        m_currentIndex = -1;
+    else if (m_currentIndex > index)
+        --m_currentIndex;
+
     m_tabBar->removeTab(index);
 }
 
@@ -167,6 +179,9 @@ void TabStackedWidget::showTab(int index)
         m_stack->setCurrentIndex(index);
     }
 
+    m_previousIndex = m_currentIndex;
+    m_currentIndex = index;
+
     // This is slot connected to ComboTabBar::currentChanged
     // We must send the signal even with invalid index (-1)
     emit currentChanged(index);
@@ -205,6 +220,12 @@ int TabStackedWidget::insertTab(int index, QWidget* w, const QString &label, boo
         index = m_stack->insertWidget(index, w);
         m_tabBar->insertTab(index, QIcon(), label, false);
     }
+
+    if (m_previousIndex >= index)
+        ++m_previousIndex;
+    if (m_currentIndex >= index)
+        ++m_currentIndex;
+
     QTimer::singleShot(0, this, SLOT(setUpLayout()));
 
     return index;
@@ -266,6 +287,9 @@ int TabStackedWidget::pinUnPinTab(int index, const QString &title)
 void TabStackedWidget::removeTab(int index)
 {
     if (QWidget* w = m_stack->widget(index)) {
+        // Select another current tab before remove, so it won't be handled by QTabBar
+        if (index == currentIndex() && count() > 1)
+            selectTabOnRemove();
         m_stack->removeWidget(w);
     }
 }
@@ -309,3 +333,37 @@ bool TabStackedWidget::validIndex(int index) const
 {
     return (index < m_stack->count() && index >= 0);
 }
+
+void TabStackedWidget::selectTabOnRemove()
+{
+    Q_ASSERT(count() > 1);
+
+    int index = -1;
+
+    switch (m_tabBar->selectionBehaviorOnRemove()) {
+    case QTabBar::SelectPreviousTab:
+        if (validIndex(m_previousIndex)) {
+            index = m_previousIndex;
+            break;
+        }
+        // fallthrough
+
+    case QTabBar::SelectLeftTab:
+        index = currentIndex() - 1;
+        if (!validIndex(index))
+            index = 1;
+        break;
+
+    case QTabBar::SelectRightTab:
+        index = currentIndex() + 1;
+        if (!validIndex(index))
+            index = currentIndex() - 1;
+        break;
+
+    default:
+        break;
+    }
+
+    Q_ASSERT(validIndex(index));
+    setCurrentIndex(index);
+}

src/lib/tabwidget/tabstackedwidget.h

@@ -81,11 +81,15 @@ protected:
 
 private:
     bool validIndex(int index) const;
+    void selectTabOnRemove();
 
     QStackedWidget* m_stack;
     ComboTabBar* m_tabBar;
     QVBoxLayout* m_mainLayout;
     bool m_dirtyTabBar;
+
+    int m_currentIndex;
+    int m_previousIndex;
 };
 
 #endif // TABSTACKEDWIDGET_H