Add example showing the benefits of using bindable properties

Added two examples for modeling a subscription service: signal/slot
connection-based and bindable property-based. The examples are based
on the example from Fabian's Qt WS talk about the bindable properties.

Pick-to: 6.2
Task-number: QTBUG-97655
Change-Id: I0345913b8b6e5c40b8477e128d36483598bdfcaa
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

7 files changed, 426 insertions, 0 deletions

diff --git a/examples/corelib/bindableproperties/shared/countries.qrc b/examples/corelib/bindableproperties/shared/countries.qrc
new file mode 100644
index 0000000000..cdf6312ebb
--- /dev/null
+++ b/examples/corelib/bindableproperties/shared/countries.qrc
@@ -0,0 +1,7 @@
+<RCC>
+    <qresource prefix="/">
+        <file>germany.png</file>
+        <file>norway.png</file>
+        <file>finland.png</file>
+    </qresource>
+</RCC>
diff --git a/examples/corelib/bindableproperties/shared/finland.png b/examples/corelib/bindableproperties/shared/finland.png
new file mode 100644
index 0000000000..92653289c1
--- /dev/null
+++ b/examples/corelib/bindableproperties/shared/finland.png
diff --git a/examples/corelib/bindableproperties/shared/germany.png b/examples/corelib/bindableproperties/shared/germany.png
new file mode 100644
index 0000000000..efc389f52a
--- /dev/null
+++ b/examples/corelib/bindableproperties/shared/germany.png
diff --git a/examples/corelib/bindableproperties/shared/norway.png b/examples/corelib/bindableproperties/shared/norway.png
new file mode 100644
index 0000000000..daee6c3c15
--- /dev/null
+++ b/examples/corelib/bindableproperties/shared/norway.png
diff --git a/examples/corelib/bindableproperties/shared/subscriptionwindow.cpp b/examples/corelib/bindableproperties/shared/subscriptionwindow.cpp
new file mode 100644
index 0000000000..03269dfa0c
--- /dev/null
+++ b/examples/corelib/bindableproperties/shared/subscriptionwindow.cpp
@@ -0,0 +1,63 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** 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.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "subscriptionwindow.h"
+#include "ui_subscriptionwindow.h"
+
+SubscriptionWindow::SubscriptionWindow(QWidget *parent)
+    : QWidget(parent), ui(new Ui::SubscriptionWindow)
+{
+    ui->setupUi(this);
+}
+
+SubscriptionWindow::~SubscriptionWindow()
+{
+    delete ui;
+}
diff --git a/examples/corelib/bindableproperties/shared/subscriptionwindow.h b/examples/corelib/bindableproperties/shared/subscriptionwindow.h
new file mode 100644
index 0000000000..9bc3acd91a
--- /dev/null
+++ b/examples/corelib/bindableproperties/shared/subscriptionwindow.h
@@ -0,0 +1,76 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** 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.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef SUBSCRIPTIONWINDOW_H
+#define SUBSCRIPTIONWINDOW_H
+
+#include <QWidget>
+
+QT_BEGIN_NAMESPACE
+namespace Ui {
+class SubscriptionWindow;
+}
+QT_END_NAMESPACE
+
+class User;
+
+class SubscriptionWindow : public QWidget
+{
+    Q_OBJECT
+
+public:
+    explicit SubscriptionWindow(QWidget *parent = nullptr);
+    ~SubscriptionWindow();
+
+private:
+    Ui::SubscriptionWindow *ui;
+};
+
+#endif // SUBSCRIPTIONWINDOW_H
diff --git a/examples/corelib/bindableproperties/shared/subscriptionwindow.ui b/examples/corelib/bindableproperties/shared/subscriptionwindow.ui
new file mode 100644
index 0000000000..7bc2931373
--- /dev/null
+++ b/examples/corelib/bindableproperties/shared/subscriptionwindow.ui
@@ -0,0 +1,280 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>SubscriptionWindow</class>
+ <widget class="QWidget" name="SubscriptionWindow">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>639</width>
+    <height>269</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Subscription</string>
+  </property>
+  <layout class="QHBoxLayout" name="horizontalLayout_5">
+   <item>
+    <layout class="QVBoxLayout" name="verticalLayout">
+     <item>
+      <layout class="QHBoxLayout" name="horizontalLayout_4" stretch="0,0,0,0">
+       <item>
+        <spacer name="horizontalSpacer_3">
+         <property name="orientation">
+          <enum>Qt::Horizontal</enum>
+         </property>
+         <property name="sizeHint" stdset="0">
+          <size>
+           <width>40</width>
+           <height>20</height>
+          </size>
+         </property>
+        </spacer>
+       </item>
+       <item>
+        <widget class="QPushButton" name="btnGermany">
+         <property name="toolTip">
+          <string>Germany</string>
+         </property>
+         <property name="text">
+          <string/>
+         </property>
+         <property name="icon">
+          <iconset>
+           <normaloff>:/germany.png</normaloff>:/germany.png</iconset>
+         </property>
+         <property name="iconSize">
+          <size>
+           <width>32</width>
+           <height>32</height>
+          </size>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <widget class="QPushButton" name="btnNorway">
+         <property name="toolTip">
+          <string>Norway</string>
+         </property>
+         <property name="text">
+          <string/>
+         </property>
+         <property name="icon">
+          <iconset>
+           <normaloff>:/norway.png</normaloff>:/norway.png</iconset>
+         </property>
+         <property name="iconSize">
+          <size>
+           <width>32</width>
+           <height>32</height>
+          </size>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <widget class="QPushButton" name="btnFinland">
+         <property name="toolTip">
+          <string>Finland</string>
+         </property>
+         <property name="text">
+          <string/>
+         </property>
+         <property name="icon">
+          <iconset>
+           <normaloff>:/finland.png</normaloff>:/finland.png</iconset>
+         </property>
+         <property name="iconSize">
+          <size>
+           <width>32</width>
+           <height>32</height>
+          </size>
+         </property>
+        </widget>
+       </item>
+      </layout>
+     </item>
+     <item>
+      <layout class="QHBoxLayout" name="horizontalLayout">
+       <item>
+        <widget class="QLabel" name="ageLabel">
+         <property name="font">
+          <font>
+           <pointsize>14</pointsize>
+           <weight>75</weight>
+           <bold>true</bold>
+          </font>
+         </property>
+         <property name="text">
+          <string>Age</string>
+         </property>
+         <property name="margin">
+          <number>3</number>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <widget class="QSpinBox" name="ageSpinBox">
+         <property name="sizePolicy">
+          <sizepolicy hsizetype="Minimum" vsizetype="Fixed">
+           <horstretch>0</horstretch>
+           <verstretch>0</verstretch>
+          </sizepolicy>
+         </property>
+         <property name="minimumSize">
+          <size>
+           <width>80</width>
+           <height>0</height>
+          </size>
+         </property>
+         <property name="value">
+          <number>0</number>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <spacer name="horizontalSpacer">
+         <property name="orientation">
+          <enum>Qt::Horizontal</enum>
+         </property>
+         <property name="sizeHint" stdset="0">
+          <size>
+           <width>40</width>
+           <height>20</height>
+          </size>
+         </property>
+        </spacer>
+       </item>
+      </layout>
+     </item>
+     <item>
+      <spacer name="verticalSpacer">
+       <property name="orientation">
+        <enum>Qt::Vertical</enum>
+       </property>
+       <property name="sizeHint" stdset="0">
+        <size>
+         <width>20</width>
+         <height>40</height>
+        </size>
+       </property>
+      </spacer>
+     </item>
+     <item>
+      <layout class="QHBoxLayout" name="horizontalLayout_2">
+       <item>
+        <widget class="QLabel" name="intervalLabel">
+         <property name="font">
+          <font>
+           <pointsize>14</pointsize>
+           <weight>75</weight>
+           <bold>true</bold>
+          </font>
+         </property>
+         <property name="text">
+          <string>Interval</string>
+         </property>
+         <property name="margin">
+          <number>3</number>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <widget class="QRadioButton" name="btnMonthly">
+         <property name="text">
+          <string>Monthly</string>
+         </property>
+         <property name="checked">
+          <bool>true</bool>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <widget class="QRadioButton" name="btnQuarterly">
+         <property name="text">
+          <string>Quarterly</string>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <widget class="QRadioButton" name="btnYearly">
+         <property name="text">
+          <string>Yearly</string>
+         </property>
+        </widget>
+       </item>
+      </layout>
+     </item>
+     <item>
+      <spacer name="verticalSpacer_2">
+       <property name="orientation">
+        <enum>Qt::Vertical</enum>
+       </property>
+       <property name="sizeHint" stdset="0">
+        <size>
+         <width>20</width>
+         <height>40</height>
+        </size>
+       </property>
+      </spacer>
+     </item>
+     <item>
+      <layout class="QHBoxLayout" name="horizontalLayout_3">
+       <item>
+        <widget class="QLabel" name="priceLabel">
+         <property name="font">
+          <font>
+           <pointsize>14</pointsize>
+           <weight>75</weight>
+           <bold>true</bold>
+          </font>
+         </property>
+         <property name="text">
+          <string>Price/month</string>
+         </property>
+         <property name="margin">
+          <number>3</number>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <widget class="QLabel" name="priceDisplay">
+         <property name="text">
+          <string>0.0</string>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <spacer name="horizontalSpacer_2">
+         <property name="orientation">
+          <enum>Qt::Horizontal</enum>
+         </property>
+         <property name="sizeHint" stdset="0">
+          <size>
+           <width>40</width>
+           <height>20</height>
+          </size>
+         </property>
+        </spacer>
+       </item>
+      </layout>
+     </item>
+     <item>
+      <spacer name="verticalSpacer_3">
+       <property name="orientation">
+        <enum>Qt::Vertical</enum>
+       </property>
+       <property name="sizeHint" stdset="0">
+        <size>
+         <width>20</width>
+         <height>40</height>
+        </size>
+       </property>
+      </spacer>
+     </item>
+    </layout>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>