Move notification example from androidextras to qtbase

Refactor android notification example to fit in qtbase. The example
demonstrates how to use JNI and work with Java APIs and add custom
Java code to a Qt app targeting Android.

Task-number: QTBUG-84382
Change-Id: I5fcbbf77b36eb47a0acaa13835ef3d773e63885c
Reviewed-by: Rami Potinkara <rami.potinkara@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Ville Voutilainen <ville.voutilainen@qt.io>

22 files changed, 613 insertions, 1 deletions

diff --git a/examples/corelib/CMakeLists.txt b/examples/corelib/CMakeLists.txt
index 9ec9dcb156..08b44649b7 100644
--- a/examples/corelib/CMakeLists.txt
+++ b/examples/corelib/CMakeLists.txt
@@ -4,6 +4,7 @@ add_subdirectory(ipc)
 add_subdirectory(mimetypes)
 add_subdirectory(serialization)
 add_subdirectory(tools)
+add_subdirectory(platform)
 if(QT_FEATURE_thread)
     add_subdirectory(threads)
 endif()
diff --git a/examples/corelib/corelib.pro b/examples/corelib/corelib.pro
index 8caf2c16df..625957ca1a 100644
--- a/examples/corelib/corelib.pro
+++ b/examples/corelib/corelib.pro
@@ -5,6 +5,7 @@ SUBDIRS = \
     ipc \
     mimetypes \
     serialization \
-    tools
+    tools \
+    platform
 
 qtConfig(thread): SUBDIRS += threads
diff --git a/examples/corelib/platform/CMakeLists.txt b/examples/corelib/platform/CMakeLists.txt
new file mode 100644
index 0000000000..1a10578a1f
--- /dev/null
+++ b/examples/corelib/platform/CMakeLists.txt
@@ -0,0 +1,3 @@
+if(ANDROID)
+    add_subdirectory(androidnotifier)
+endif()
diff --git a/examples/corelib/platform/androidnotifier/CMakeLists.txt b/examples/corelib/platform/androidnotifier/CMakeLists.txt
new file mode 100644
index 0000000000..1dca63faf2
--- /dev/null
+++ b/examples/corelib/platform/androidnotifier/CMakeLists.txt
@@ -0,0 +1,55 @@
+cmake_minimum_required(VERSION 3.14)
+project(androidnotifier LANGUAGES CXX)
+
+set(CMAKE_INCLUDE_CURRENT_DIR ON)
+
+set(CMAKE_AUTOMOC ON)
+set(CMAKE_AUTORCC ON)
+set(CMAKE_AUTOUIC ON)
+
+if(NOT DEFINED INSTALL_EXAMPLESDIR)
+  set(INSTALL_EXAMPLESDIR "examples")
+endif()
+
+find_package(QT NAMES Qt6 Qt5 COMPONENTS Widgets REQUIRED)
+find_package(Qt${QT_VERSION_MAJOR} COMPONENTS Widgets REQUIRED)
+
+set(INSTALL_EXAMPLEDIR "${INSTALL_EXAMPLESDIR}/corelib/platform/androidnotifier")
+
+set(PROJECT_SOURCES
+        main.cpp
+        notificationclient.cpp
+        notificationclient.h
+)
+
+if(ANDROID)
+    qt_add_executable(androidnotifier
+        MANUAL_FINALIZATION
+        ${PROJECT_SOURCES})
+    target_link_libraries(androidnotifier PRIVATE Qt${QT_VERSION_MAJOR}::Widgets)
+
+    set_property(TARGET androidnotifier APPEND PROPERTY QT_ANDROID_PACKAGE_SOURCE_DIR
+                 ${CMAKE_CURRENT_SOURCE_DIR}/android)
+
+    if(QT_VERSION_MAJOR EQUAL 6)
+        qt_finalize_executable(androidnotifier)
+    endif()
+
+    set(qml_resource_files
+        "images/happy.png"
+        "images/sad.png"
+    )
+
+    qt6_add_resources(androidnotifier "main"
+        PREFIX
+            "/"
+        FILES
+            ${qml_resource_files}
+    )
+
+    install(TARGETS androidnotifier
+        RUNTIME DESTINATION "${INSTALL_EXAMPLEDIR}"
+        BUNDLE DESTINATION "${INSTALL_EXAMPLEDIR}"
+        LIBRARY DESTINATION "${INSTALL_EXAMPLEDIR}"
+    )
+endif()
diff --git a/examples/corelib/platform/androidnotifier/android/AndroidManifest.xml b/examples/corelib/platform/androidnotifier/android/AndroidManifest.xml
new file mode 100644
index 0000000000..d53be9b3f3
--- /dev/null
+++ b/examples/corelib/platform/androidnotifier/android/AndroidManifest.xml
@@ -0,0 +1,76 @@
+<?xml version="1.0"?>
+<manifest package="org.qtproject.example.androidnotifier" xmlns:android="http://schemas.android.com/apk/res/android" android:versionName="1.0" android:versionCode="1" android:installLocation="auto">
+
+    <!-- The following comment will be replaced upon deployment with default permissions based on the dependencies of the application.
+         Remove the comment if you do not require these default permissions. -->
+    <!-- %%INSERT_PERMISSIONS -->
+
+    <!-- The following comment will be replaced upon deployment with default features based on the dependencies of the application.
+         Remove the comment if you do not require these default features. -->
+    <!-- %%INSERT_FEATURES -->
+
+    <supports-screens android:largeScreens="true" android:normalScreens="true" android:anyDensity="true" android:smallScreens="true"/>
+
+    <application android:hardwareAccelerated="true" android:name="org.qtproject.qt.android.bindings.QtApplication" android:label="Qt Notifier" android:extractNativeLibs="true" android:icon="@drawable/icon">
+        <activity android:configChanges="orientation|uiMode|screenLayout|screenSize|smallestScreenSize|layoutDirection|locale|fontScale|keyboard|keyboardHidden|navigation|mcc|mnc|density" android:name="org.qtproject.qt.android.bindings.QtActivity" android:label="-- %%INSERT_APP_NAME%% --" android:screenOrientation="unspecified" android:launchMode="singleTop">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN"/>
+                <category android:name="android.intent.category.LAUNCHER"/>
+            </intent-filter>
+            <!-- Application arguments -->
+            <!-- meta-data android:name="android.app.arguments" android:value="arg1 arg2 arg3"/ -->
+            <!-- Application arguments -->
+            <meta-data android:name="android.app.lib_name" android:value="-- %%INSERT_APP_LIB_NAME%% --"/>
+            <meta-data android:name="android.app.qt_sources_resource_id" android:resource="@array/qt_sources"/>
+            <meta-data android:name="android.app.repository" android:value="default"/>
+            <meta-data android:name="android.app.qt_libs_resource_id" android:resource="@array/qt_libs"/>
+            <meta-data android:name="android.app.bundled_libs_resource_id" android:resource="@array/bundled_libs"/>
+            <!-- Deploy Qt libs as part of package -->
+            <meta-data android:name="android.app.bundle_local_qt_libs" android:value="-- %%BUNDLE_LOCAL_QT_LIBS%% --"/>
+            <!-- Run with local libs -->
+            <meta-data android:name="android.app.use_local_qt_libs" android:value="-- %%USE_LOCAL_QT_LIBS%% --"/>
+            <meta-data android:name="android.app.libs_prefix" android:value="/data/local/tmp/qt/"/>
+            <meta-data android:name="android.app.load_local_libs_resource_id" android:resource="@array/load_local_libs"/>
+            <meta-data android:name="android.app.load_local_jars" android:value="-- %%INSERT_LOCAL_JARS%% --"/>
+            <meta-data android:name="android.app.static_init_classes" android:value="-- %%INSERT_INIT_CLASSES%% --"/>
+            <!-- Used to specify custom system library path to run with local system libs -->
+            <!-- <meta-data android:name="android.app.system_libs_prefix" android:value="/system/lib/"/> -->
+            <!--  Messages maps -->
+            <meta-data android:value="@string/ministro_not_found_msg" android:name="android.app.ministro_not_found_msg"/>
+            <meta-data android:value="@string/ministro_needed_msg" android:name="android.app.ministro_needed_msg"/>
+            <meta-data android:value="@string/fatal_error_msg" android:name="android.app.fatal_error_msg"/>
+            <meta-data android:value="@string/unsupported_android_version" android:name="android.app.unsupported_android_version"/>
+            <!--  Messages maps -->
+            <!-- Splash screen -->
+            <!-- Orientation-specific (portrait/landscape) data is checked first. If not available for current orientation,
+                 then android.app.splash_screen_drawable. For best results, use together with splash_screen_sticky and
+                 use hideSplashScreen() with a fade-out animation from Qt Android Extras to hide the splash screen when you
+                 are done populating your window with content. -->
+            <!-- meta-data android:name="android.app.splash_screen_drawable_portrait" android:resource="@drawable/logo_portrait" / -->
+            <!-- meta-data android:name="android.app.splash_screen_drawable_landscape" android:resource="@drawable/logo_landscape" / -->
+            <!-- meta-data android:name="android.app.splash_screen_drawable" android:resource="@drawable/logo"/ -->
+            <!-- meta-data android:name="android.app.splash_screen_sticky" android:value="true"/ -->
+            <!-- Splash screen -->
+            <!-- Background running -->
+            <!-- Warning: changing this value to true may cause unexpected crashes if the
+                          application still try to draw after
+                          "applicationStateChanged(Qt::ApplicationSuspended)"
+                          signal is sent! -->
+            <meta-data android:name="android.app.background_running" android:value="false"/>
+            <!-- Background running -->
+            <!-- auto screen scale factor -->
+            <meta-data android:name="android.app.auto_screen_scale_factor" android:value="false"/>
+            <!-- auto screen scale factor -->
+            <!-- extract android style -->
+            <!-- available android:values :
+                * default - In most cases this will be the same as "full", but it can also be something else if needed, e.g., for compatibility reasons
+                * full - useful QWidget & Quick Controls 1 apps
+                * minimal - useful for Quick Controls 2 apps, it is much faster than "full"
+                * none - useful for apps that don't use any of the above Qt modules
+                -->
+            <meta-data android:name="android.app.extract_android_style" android:value="none"/>
+            <!-- extract android style -->
+        </activity>
+        <!-- For adding service(s) please check: https://wiki.qt.io/AndroidServices -->
+    </application>
+</manifest>
diff --git a/examples/corelib/platform/androidnotifier/android/res/drawable-hdpi/icon.png b/examples/corelib/platform/androidnotifier/android/res/drawable-hdpi/icon.png
new file mode 100644
index 0000000000..d3ccebe1f2
--- /dev/null
+++ b/examples/corelib/platform/androidnotifier/android/res/drawable-hdpi/icon.png
diff --git a/examples/corelib/platform/androidnotifier/android/res/drawable-ldpi/icon.png b/examples/corelib/platform/androidnotifier/android/res/drawable-ldpi/icon.png
new file mode 100644
index 0000000000..2194be145e
--- /dev/null
+++ b/examples/corelib/platform/androidnotifier/android/res/drawable-ldpi/icon.png
diff --git a/examples/corelib/platform/androidnotifier/android/res/drawable-mdpi/icon.png b/examples/corelib/platform/androidnotifier/android/res/drawable-mdpi/icon.png
new file mode 100644
index 0000000000..31812ccdd9
--- /dev/null
+++ b/examples/corelib/platform/androidnotifier/android/res/drawable-mdpi/icon.png
diff --git a/examples/corelib/platform/androidnotifier/android/res/drawable-xhdpi/icon.png b/examples/corelib/platform/androidnotifier/android/res/drawable-xhdpi/icon.png
new file mode 100644
index 0000000000..3aeae642d9
--- /dev/null
+++ b/examples/corelib/platform/androidnotifier/android/res/drawable-xhdpi/icon.png
diff --git a/examples/corelib/platform/androidnotifier/android/res/drawable-xxhdpi/icon.png b/examples/corelib/platform/androidnotifier/android/res/drawable-xxhdpi/icon.png
new file mode 100644
index 0000000000..f754fd18ae
--- /dev/null
+++ b/examples/corelib/platform/androidnotifier/android/res/drawable-xxhdpi/icon.png
diff --git a/examples/corelib/platform/androidnotifier/android/res/drawable-xxxhdpi/icon.png b/examples/corelib/platform/androidnotifier/android/res/drawable-xxxhdpi/icon.png
new file mode 100644
index 0000000000..d0d043bf9c
--- /dev/null
+++ b/examples/corelib/platform/androidnotifier/android/res/drawable-xxxhdpi/icon.png
diff --git a/examples/corelib/platform/androidnotifier/android/src/org/qtproject/example/androidnotifier/NotificationClient.java b/examples/corelib/platform/androidnotifier/android/src/org/qtproject/example/androidnotifier/NotificationClient.java
new file mode 100644
index 0000000000..c43513b17a
--- /dev/null
+++ b/examples/corelib/platform/androidnotifier/android/src/org/qtproject/example/androidnotifier/NotificationClient.java
@@ -0,0 +1,93 @@
+/****************************************************************************
+**
+** 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."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+package org.qtproject.example.androidnotifier;
+
+import android.app.Notification;
+import android.app.NotificationManager;
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.Color;
+import android.graphics.BitmapFactory;
+import android.app.NotificationChannel;
+
+public class NotificationClient
+{
+    public static void notify(Context context, String message) {
+        try {
+            NotificationManager m_notificationManager = (NotificationManager)
+                    context.getSystemService(Context.NOTIFICATION_SERVICE);
+
+            Notification.Builder m_builder;
+            if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
+                int importance = NotificationManager.IMPORTANCE_DEFAULT;
+                NotificationChannel notificationChannel;
+                notificationChannel = new NotificationChannel("Qt", "Qt Notifier", importance);
+                m_notificationManager.createNotificationChannel(notificationChannel);
+                m_builder = new Notification.Builder(context, notificationChannel.getId());
+            } else {
+                m_builder = new Notification.Builder(context);
+            }
+
+            Bitmap icon = BitmapFactory.decodeResource(context.getResources(), R.drawable.icon);
+            m_builder.setSmallIcon(R.drawable.icon)
+                    .setLargeIcon(icon)
+                    .setContentTitle("A message from Qt!")
+                    .setContentText(message)
+                    .setDefaults(Notification.DEFAULT_SOUND)
+                    .setColor(Color.GREEN)
+                    .setAutoCancel(true);
+
+            m_notificationManager.notify(0, m_builder.build());
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+}
diff --git a/examples/corelib/platform/androidnotifier/androidnotifier.pro b/examples/corelib/platform/androidnotifier/androidnotifier.pro
new file mode 100644
index 0000000000..f1650c1911
--- /dev/null
+++ b/examples/corelib/platform/androidnotifier/androidnotifier.pro
@@ -0,0 +1,20 @@
+QT += core gui
+greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
+
+SOURCES += \
+    main.cpp \
+    notificationclient.cpp
+
+HEADERS += \
+    notificationclient.h
+
+RESOURCES += \
+    main.qrc
+
+target.path = $$[QT_INSTALL_EXAMPLES]/corelib/platform/androidnotifier
+INSTALLS += target
+
+ANDROID_PACKAGE_SOURCE_DIR = $$PWD/android
+OTHER_FILES += \
+    android/src/org/qtproject/example/androidnotifier/NotificationClient.java \
+    android/AndroidManifest.xml
diff --git a/examples/corelib/platform/androidnotifier/doc/images/androidnotifier.png b/examples/corelib/platform/androidnotifier/doc/images/androidnotifier.png
new file mode 100644
index 0000000000..36a4a50c47
--- /dev/null
+++ b/examples/corelib/platform/androidnotifier/doc/images/androidnotifier.png
diff --git a/examples/corelib/platform/androidnotifier/doc/src/androidnotifier-example.qdoc b/examples/corelib/platform/androidnotifier/doc/src/androidnotifier-example.qdoc
new file mode 100644
index 0000000000..b1e4243d56
--- /dev/null
+++ b/examples/corelib/platform/androidnotifier/doc/src/androidnotifier-example.qdoc
@@ -0,0 +1,84 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: http://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.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*!
+    \title Qt Android Notifier
+    \example platform/androidnotifier
+    \brief Demonstrates calling Java code from Qt in an Android application.
+
+    \image androidnotifier.png
+
+    This example demonstrates how to add a custom Java class to an Android
+    application, and how to call it using the JNI convenience APIs in Qt.
+
+    Click on one of the smiley faces to send a notification in the status bar
+    of the Android screen.
+
+    \include examples-run.qdocinc
+
+    \section1 Calling Java Methods from C++ Code
+
+    We define a custom Java class called \c NotificationClient in the
+    NotificationClient.java file:
+
+    \quotefromfile platform/androidnotifier/android/src/org/qtproject/example/androidnotifier/NotificationClient.java
+    \skipto org.qtproject.example.androidnotifier
+    \printuntil /^\}/
+
+    In the NotificationClient C++ class header file, \c notificationclient.h, we
+    declare a simple C++ API to display notifications on an Android device. It
+    consists of a single string property, \c notification, and a slot,
+    \c updateAndroidNotification(), that calls the Java code:
+
+    \snippet platform/androidnotifier/notificationclient.h Qt Notification Class
+
+    We connect the \c notificationChanged() signal to the
+    \c updateAndroidNotification() slot to update the notification text when the
+    \c notification text changes:
+
+    \snippet platform/androidnotifier/notificationclient.cpp notification changed signal
+
+    The \c updateAndroidNotification() function calls the Java method responsible
+    for sending the notification from the Android platform APIs. First, we construct
+    a Java string \c jstring from the notification string, then pass the \c jstring
+    object as a parameter to the \c notify() method in Java:
+
+    \snippet platform/androidnotifier/notificationclient.cpp Send notification message to Java
+
+    The call to the Java meethod use \l QJniObject which relies on the Java Native
+    Interface (JNI) APIs to communicate with Java. Also, in the previous snippet,
+    we are passing the app's context object which the the static Java code can use
+    to tap into the app's specific properties and APIs.
+
+    To make sure our smiley buttons do what they are supposed to, we add the
+    the following code to change the notification text if either of them are
+    clicked:
+
+    \snippet platform/androidnotifier/main.cpp Connect button signals
+
+    \sa {Qt for Android}
+*/
diff --git a/examples/corelib/platform/androidnotifier/images/happy.png b/examples/corelib/platform/androidnotifier/images/happy.png
new file mode 100644
index 0000000000..af9412c2fb
--- /dev/null
+++ b/examples/corelib/platform/androidnotifier/images/happy.png
diff --git a/examples/corelib/platform/androidnotifier/images/sad.png b/examples/corelib/platform/androidnotifier/images/sad.png
new file mode 100644
index 0000000000..928184b413
--- /dev/null
+++ b/examples/corelib/platform/androidnotifier/images/sad.png
diff --git a/examples/corelib/platform/androidnotifier/main.cpp b/examples/corelib/platform/androidnotifier/main.cpp
new file mode 100644
index 0000000000..8b2e937351
--- /dev/null
+++ b/examples/corelib/platform/androidnotifier/main.cpp
@@ -0,0 +1,103 @@
+/****************************************************************************
+**
+** 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 "notificationclient.h"
+
+#include <QApplication>
+#include <QWidget>
+#include <QPushButton>
+#include <QHBoxLayout>
+#include <QLabel>
+#include <QFont>
+
+int main(int argc, char *argv[])
+{
+    QApplication a(argc, argv);
+
+    QWidget widget;
+    QPushButton happyButton;
+    happyButton.setIcon(QIcon(":/images/happy.png"));
+    happyButton.setIconSize(QSize(happyButton.width(), 120));
+
+    QPushButton sadButton;
+    sadButton.setIcon(QIcon(":/images/sad.png"));
+    sadButton.setIconSize(QSize(sadButton.width(), 120));
+
+    QVBoxLayout mainLayout;
+    QHBoxLayout labelLayout;
+    QLabel label = QLabel("Click a smiley to notify your mood");
+    QFont font = label.font();
+    font.setPointSize(20);
+    label.setFont(font);
+    labelLayout.addWidget(&label);
+    labelLayout.setAlignment(Qt::AlignHCenter);
+    mainLayout.addLayout(&labelLayout);
+
+    QHBoxLayout smileysLayout;
+    smileysLayout.addWidget(&sadButton);
+    smileysLayout.addWidget(&happyButton);
+    smileysLayout.setAlignment(Qt::AlignCenter);
+    mainLayout.addLayout(&smileysLayout);
+    widget.setLayout(&mainLayout);
+
+//! [Connect button signals]
+    QObject::connect(&happyButton, &QPushButton::clicked, []() {
+        NotificationClient().setNotification("The user is happy!");
+    });
+
+    QObject::connect(&sadButton, &QPushButton::clicked, []() {
+        NotificationClient().setNotification("The user is sad!");
+    });
+//! [Connect button signals]
+
+    widget.show();
+    return a.exec();
+}
+
diff --git a/examples/corelib/platform/androidnotifier/main.qrc b/examples/corelib/platform/androidnotifier/main.qrc
new file mode 100644
index 0000000000..e0bb052fd2
--- /dev/null
+++ b/examples/corelib/platform/androidnotifier/main.qrc
@@ -0,0 +1,6 @@
+<RCC>
+    <qresource prefix="/">
+        <file>images/happy.png</file>
+        <file>images/sad.png</file>
+    </qresource>
+</RCC>
diff --git a/examples/corelib/platform/androidnotifier/notificationclient.cpp b/examples/corelib/platform/androidnotifier/notificationclient.cpp
new file mode 100644
index 0000000000..b2093234b9
--- /dev/null
+++ b/examples/corelib/platform/androidnotifier/notificationclient.cpp
@@ -0,0 +1,90 @@
+/****************************************************************************
+**
+** 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 "notificationclient.h"
+
+#include <QtCore/qjniobject.h>
+#include <QtCore/qcoreapplication.h>
+
+NotificationClient::NotificationClient(QObject *parent)
+    : QObject(parent)
+{
+    connect(this, &NotificationClient::notificationChanged,
+            this, &NotificationClient::updateAndroidNotification);
+}
+
+void NotificationClient::setNotification(const QString &notification)
+{
+    if (m_notification == notification)
+        return;
+
+//! [notification changed signal]
+    m_notification = notification;
+    emit notificationChanged();
+//! [notification changed signal]
+}
+
+QString NotificationClient::notification() const
+{
+    return m_notification;
+}
+
+//! [Send notification message to Java]
+void NotificationClient::updateAndroidNotification()
+{
+    QJniObject javaNotification = QJniObject::fromString(m_notification);
+    QJniObject::callStaticMethod<void>(
+                    "org/qtproject/example/androidnotifier/NotificationClient",
+                    "notify",
+                    "(Landroid/content/Context;Ljava/lang/String;)V",
+                    QNativeInterface::QAndroidApplication::context(),
+                    javaNotification.object<jstring>());
+}
+//! [Send notification message to Java]
diff --git a/examples/corelib/platform/androidnotifier/notificationclient.h b/examples/corelib/platform/androidnotifier/notificationclient.h
new file mode 100644
index 0000000000..f821dbfc8d
--- /dev/null
+++ b/examples/corelib/platform/androidnotifier/notificationclient.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 NOTIFICATIONCLIENT_H
+#define NOTIFICATIONCLIENT_H
+
+#include <QObject>
+
+//! [Qt Notification Class]
+class NotificationClient : public QObject
+{
+    Q_OBJECT
+public:
+    explicit NotificationClient(QObject *parent = 0);
+
+    void setNotification(const QString &notification);
+    QString notification() const;
+
+signals:
+    void notificationChanged();
+
+private slots:
+    void updateAndroidNotification();
+
+private:
+    QString m_notification;
+};
+//! [Qt Notification Class]
+#endif // NOTIFICATIONCLIENT_H
diff --git a/examples/corelib/platform/platform.pro b/examples/corelib/platform/platform.pro
new file mode 100644
index 0000000000..b9e58c7c7e
--- /dev/null
+++ b/examples/corelib/platform/platform.pro
@@ -0,0 +1,4 @@
+TEMPLATE = subdirs
+CONFIG += no_docs_target
+
+android: SUBDIRS += androidnotifier