Add bar chart example

Example shows using setBarSelected().
Selecting bars changes their color and information of selected/unselected bars.
[QtCharts][Example] Added Example

Task-number: QTBUG-89445
Change-Id: Ic863e763d2cfa552629f42afd1232c1f77b95e95
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>
(cherry picked from commit 72d69b22d8da004fcb27e1a549cdda3f52b9c4af)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

2 files changed, 69 insertions, 0 deletions

diff --git a/src/charts/doc/images/examples_selectedbar.png b/src/charts/doc/images/examples_selectedbar.png
new file mode 100644
index 00000000..0b425aeb
--- /dev/null
+++ b/src/charts/doc/images/examples_selectedbar.png
diff --git a/src/charts/doc/src/examples-selectedbar.qdoc b/src/charts/doc/src/examples-selectedbar.qdoc
new file mode 100644
index 00000000..72c6a34c
--- /dev/null
+++ b/src/charts/doc/src/examples-selectedbar.qdoc
@@ -0,0 +1,69 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:FDL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Free Documentation License Usage
+** Alternatively, this file may be used under the terms of the GNU Free
+** Documentation License version 1.3 as published by the Free Software
+** Foundation and appearing in the file included in the packaging of
+** this file. Please review the following information to ensure
+** the GNU Free Documentation License version 1.3 requirements
+** will be met: https://www.gnu.org/licenses/fdl-1.3.html.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*!
+    \example selectedbar
+    \title SelectedBar Example
+    \ingroup qtcharts_examples
+
+    \brief The example shows how to use a selection feature for the bar chart.
+
+    The example shows changing the color and state of bars using the selection feature.
+
+    \image examples_selectedbar.png
+
+    \include examples-run.qdocinc
+
+    \section1 Using setBarSelected()
+
+    We create the sets and fill them with the data. Then we create a series and append data to it.
+    \snippet selectedbar/main.cpp 1
+
+    We create the chart and add series to it.
+    Also, we add a title to the chart, set animation for the chart, and align the legend.
+    \snippet selectedbar/main.cpp 2
+
+    Here we set the color for the selected bars.
+    \snippet selectedbar/main.cpp 3
+
+    Next step is adding axes:
+    QBarCategoryAxis for years of measurements and QValueAxis for values range.
+    \snippet selectedbar/main.cpp 4
+
+    Then we add the chart view to put the chart in.
+    \snippet selectedbar/main.cpp 5
+
+    Here we create a widget for labels of values of selected and unselected bars.
+    \snippet selectedbar/main.cpp 6
+
+    We connect selecting of a specific bar with labels of values using a lambda.
+    \c {set->toggleSelection({index})} sets the bar selected.
+    \snippet selectedbar/main.cpp 7
+
+    Finally, we create the main widget and add other layouts to it and run the application.
+    \snippet selectedbar/main.cpp 8
+*/