// Copyright (C) 2021 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only

/*!
    \title \Q4A Notifier
    \example platform/androidnotifier
    \meta tag {widgets,android,notification}
    \brief Demonstrates calling Java code from Qt in an Android application.
    \ingroup androidplatform
    \ingroup corelib_examples

    \image androidnotifier.png {Android notification panel showing Qt
           Notifier message with happy and sad smiley buttons}

    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 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 {\Q4A}
*/
