Add Android Service examples with Remote Objects

Additional service examples with communication using Qt Remote Objects.

Task-number: QTBUG-83038
Change-Id: I6451c816681e314bd4f47c8966c5d98cd225e64d
Reviewed-by: Ville Voutilainen <ville.voutilainen@qt.io>
(cherry picked from commit d560ad9f356e2f5912b0ebabde4c001efcb9b31f)

1 files changed, 183 insertions, 0 deletions

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+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtAndroidExtras module of the Qt Toolkit.
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+****************************************************************************/
+
+/*!
+    \title Android Service with Qt Remote Objects
+    \ingroup examples-qtandroidextras
+    \example services/serviceremoteobjects
+    \brief Demonstrates how to run an Android service in a separate process,
+           and how to communicate between the service process and the main process
+           using Qt Remote Objects.
+
+    \image androidservices.png
+
+    This example demonstrates how to create and run an Android service in
+    a separate process from the main application process, and then exchange data
+    between QML/C++ and the Java service using \l{Qt Remote Objects}.
+
+    When clicking the \uicontrol {Send to Service} button, the name entered in the QML
+    view, Qt, in this case, is sent to the Android service. Then, the service
+    replies back with a message \c {Hello Qt} which is printed in the QML view.
+
+    \include examples-run.qdocinc
+
+    \section1 Create the Service
+
+    To start a service in its own process, extend the \c QtService class for
+    your service. Extending \c QtService allows the service to load the necessary
+    Qt libraries used for Qt, like \l{Qt Remote Objects} libraries.
+
+    Start by creating the Java service class. The following class extends \c QtService
+    and acts as your service entry point:
+
+    \quotefromfile services/serviceremoteobjects/android/src/org/qtproject/example/qtandroidservice/QtAndroidService.java
+    \skipto package
+    \printuntil /^\}/
+
+    This class can have any logic you want using Java code. However, you don't need
+    any logic to communicate with Qt as that will be done using Qt Remote Objects.
+
+    \section1 Manage the AndroidManifest.xml File
+
+    To use the service, it must be declared in the \c AndroidManifest.xml
+    file as follows:
+
+    \quotefromfile services/serviceremoteobjects/android/AndroidManifest.xml
+    \skipto <service
+    \printuntil </service>
+
+    The important part of this service declaration is the \c lib_name part.
+    It will ensure that the service is run by the service's own lib file:
+
+    \quotefromfile services/serviceremoteobjects/android/AndroidManifest.xml
+    \skipto android:value="service"
+    \printuntil android:value="service"
+
+    \section1 Handle the Application Start
+
+    To start the service, call the following function from the application's
+    \c main():
+
+    \quotefromfile services/serviceremoteobjects/main.cpp
+    \skipto startService
+    \printuntil /^\}/
+
+    \section1 Handle the Service Start
+
+    \l{QAndroidService} is used to create the service process. For the service
+    to start from its own \c .so lib file, create a sub-project with the following
+    \c .pro file:
+
+    \quotefromfile services/serviceremoteobjects/service.pro
+    \printuntil CONFIG
+
+    \section1 Communication with Qt Remote Objects
+
+    To use \l{Qt Remote Objects}, define a \c .rep file:
+
+    \quotefromfile services/common/qtandroidservice.rep
+    \skipto class
+    \printuntil /^\}/
+
+    Define the \c .rep source file in the service project \c .pro:
+
+    \quotefromfile services/serviceremoteobjects/service.pro
+    \skipto REPC_SOURCE
+    \printline REPC_SOURCE
+
+    And in the application's \c .pro file:
+
+    \quotefromfile services/serviceremoteobjects/serviceremoteobjectsclient.pro
+    \skipto REPC_REPLICA
+    \printline REPC_REPLICA
+
+    Then define the class used by Qt Remote Objects, which has a
+    \c sendToService() slot and a \c messageFromService() signal:
+
+    \quotefromfile services/common/qtandroidservice_ro.h
+    \skipto include
+    \printuntil /^\};/
+
+    Include the class in the previous snippet in \c main.cpp:
+
+    \quotefromfile services/serviceremoteobjects/main.cpp
+    \skipto _replica.h
+    \printline _replica.h
+
+    Now, in the service's \c service_main.cpp, create the \l{QRemoteObjectHost}
+    node and start \l{QAndroidService}:
+
+    \quotefromfile services/serviceremoteobjects/service_main.cpp
+    \skipto include
+    \printuntil /^\}/
+
+    In the application's \c main.cpp, create the client node and connect it
+    to the source node created in the service and connect it to the QML view:
+
+    \quotefromfile services/serviceremoteobjects/main.cpp
+    \skipto QRemoteObjectNode
+    \printuntil sendToService
+
+    Then, add a \l Connections element to watch for the incoming messages from
+    the service:
+
+    \quotefromfile services/common/main.qml
+    \skipto Connections
+    \printuntil /^\ {4}\}/
+
+    And set the \c onClicked for the sending button to:
+
+    \quotefromfile services/common/main.qml
+    \skipto onClicked
+    \printline onClicked
+
+    \sa {Android Service with Qt Remote Objects - Same Lib File},
+        {Android Services}, {Qt for Android}, {Qt Android Extras}
+*/