Qt Android Services. Documentation and reality.

[KroMignon]

@T-Kloczko I have create an Android App with 1 activity and 3 services with Qt 5.12.7, and it works fine.
A first look, I can't understand why it doesn't work for you.
Maybe you should use full quantified name in manifest:

<service android:process=":qt" android:name="fr.inria.blue.BluePeripheral" android:exported="true">

[T. Kloczko]

@KroMignon

Hi, unfortunately, the full name does not change anything. Moreover, using Qt 5.12.7 brings other problems. Firstly, we need to use android ndk 19rc to avoid compilation warnings. Then we get link warnings such as

Warning: "/data/app/fr.inria.test-AyWWvb8GkSDR8Mx2Zhjtjw==/lib/x86/libQt5AndroidExtras.so" has unsupported flags DT_FLAGS_1=0x80 (ignoring unsupported flags)

and finally an error occurs

E fr.inria.test: No implementation found for int[] org.qtproject.qt5.android.ExtractStyle.extractNativeChunkInfo20(long) (tried Java_org_qtproject_qt5_android_ExtractStyle_extractNativeChunkInfo20 and Java_org_qtproject_qt5_android_ExtractStyle_extractNativeChunkInfo20__J)

I made a lightweight program that reproduces the bug https://gitlab.inria.fr/tkloczko/qt-service-test.
But we encounter exactly the same problem with the sample code of Kdab example.
Any hint would be great !

I made an issue ont Qt-Bug tracker https://bugreports.qt.io/browse/QTBUG-83288. Hope this will brings some answers.
Thanks again for your help.

Sincerely,
Thibaud.

[KroMignon]

@T-Kloczko I've got a little question to you: how to you know service is started or not?
Your Android Service and Activity runs in different processes, but with Qt Creator you can only debug 1 process, which will be the Activity.

To see if you Service has started, you have to use a tool to monitor android logs, for example with Android Studio or mLogCat.

[T. Kloczko]

@KroMignon Hi, yes we use ncat stuff to trace that the service was started.
Now we gonna try to launch the websocket server through a call to a static c function... we'll see :-/ !
Thib.

[T. Kloczko]

@KroMignon Hi, finally I used logcat stuff from Android and here is the log I obtain:

2020-04-06 11:39:16.713 9577-9577/? I/r.inria.test:q: Not late-enabling -Xcheck:jni (already on)
2020-04-06 11:39:16.743 9577-9577/? E/r.inria.test:q: Unknown bits set in runtime_flags: 0x8000
2020-04-06 11:39:16.744 9577-9577/? W/r.inria.test:q: Unexpected CPU variant for X86 using defaults: x86
2020-04-06 11:39:16.798 9577-9577/fr.inria.test:qt D/SERVICE: ON CREATE CALLED
2020-04-06 11:39:16.798 9577-9577/fr.inria.test:qt I/Service: Created
2020-04-06 11:39:16.800 9577-9577/fr.inria.test:qt E/r.inria.test:q: Invalid ID 0x00000000.
2020-04-06 11:39:16.802 9577-9577/fr.inria.test:qt E/Qt: Can't create main activity
    android.content.res.Resources$NotFoundException: String array resource ID #0x0
        at android.content.res.Resources.getStringArray(Resources.java:604)
        at org.qtproject.qt5.android.bindings.QtLoader.startApp(QtLoader.java:423)
        at org.qtproject.qt5.android.bindings.QtServiceLoader.onCreate(QtServiceLoader.java:60)
        at org.qtproject.qt5.android.bindings.QtService.onCreateHook(QtService.java:54)
        at org.qtproject.qt5.android.bindings.QtService.onCreate(QtService.java:60)
        at fr.inria.test.MyTest.onCreate(MyTest.java:29)
        at android.app.ActivityThread.handleCreateService(ActivityThread.java:3953)
        at android.app.ActivityThread.access$1500(ActivityThread.java:219)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1875)
        at android.os.Handler.dispatchMessage(Handler.java:107)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
2020-04-06 11:39:16.802 9577-9577/fr.inria.test:qt I/Service: Created

It seems that it wants to create another main activity... I am really lost...
Thib

[T. Kloczko]

@KroMignon I FOUND IT !!!!
Thanks to this thread:
https://lists.qt-project.org/pipermail/interest/2020-January/034372.html
In fact, at least for Qt 5.14. x, the part of the manifest that must be used is as follows:

 <service android:process=":in" android:name=".MyTest" android:exported="true">
        <!-- android:process=":qt" is needed to force the service to run on a separate process than the Activity -->

            <!-- Application arguments -->
            <meta-data android:name="android.app.arguments" android:value="-service"/>
            <!-- Application arguments -->

            <!-- If you are using the same application (.so file) for activity and also for service, then you
                 need to use *android.app.arguments* to pass some arguments to your service in order to know which
                 one is which.
            -->

            <!-- Application to launch -->
            <meta-data android:name="android.app.lib_name" android:value="-- %%INSERT_APP_LIB_NAME%% --"/>
            <!-- Application to launch -->

            <!-- Ministro -->
            <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"/>
            <!-- Ministro -->

            <!-- Deploy Qt libs as part of package -->
            <meta-data android:name="android.app.bundle_local_qt_libs" android:value="-- %%BUNDLE_LOCAL_QT_LIBS%% --"/>
            <!-- Deploy Qt libs as part of package -->

            <!-- 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%% --"/>
            <!-- Run with local libs -->

            <!--  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 -->


            <!-- Background running -->
            <meta-data android:name="android.app.background_running" android:value="true"/>
            <!-- Background running -->
        </service>

Compare to the one given https://wiki.qt.io/AndroidServices, one should remove the following lines:

<meta-data android:name="android.app.bundled_in_lib_resource_id" android:resource="@array/bundled_in_lib"/>
<meta-data android:name="android.app.bundled_in_assets_resource_id" android:resource="@array/bundled_in_assets"/>

One should replace the following line:

<meta-data android:name="android.app.load_local_libs" android:value="-- %%INSERT_LOCAL_LIBS%% --"/>

by this one

<meta-data android:name="android.app.load_local_libs_resource_id" android:resource="@array/load_local_libs"/>

And finally, one has to add the following line:

<meta-data android:value="@string/unsupported_android_version" android:name="android.app.unsupported_android_version"/>

Clearly, the wiki should at least mention this ;-) !

Thanks again for the help,
Sincerely,
Thibaud.

[Pablo J. Rogina]

@T-Kloczko said in Qt Android Services. Documentation and reality.:

I FOUND IT !!!!

It looks like you solved your issue. If so, please don't forget to mark your post as such.

the wiki should at least mention this ;-) !

You're more than welcome to edit/improve the wiki, just login using the same account you use in this forum.

Thanks.

[T. Kloczko]

@Pablo-J-Rogina OK thanks ! I would like to do it but it seems I have not enough privilege.

For the wiki part, I tried to modify it but I realize I was not logged :-/ !

Thanks again for the work the whole team does !

Cheers Thibaud.

[T. Kloczko]

@Pablo-J-Rogina In fact it seems that I do not have enough privilege to mark it as the right answer :-( ...

[SGaist]

Hi,

IIRC, that's an issue of NodeBB. Which answer would you like to mark as the right one ?

[T. Kloczko]

@SGaist Hi, the right answer is the one of 8 hours ago.

[SGaist]

Is it correct ?

[Kanstancin]

@T-Kloczko Hi!
I've faced the same issue, but after I made fixes proposed by you to AndroidManifest, the problem still had not solved.
Please, if you managed to start the service from the application, can you post somewhere a minimal working example of the project?

Thanks in advance,
Kastuś.