Qt6 Gettting Android Battery Data.

[SMF-Qt]

I have a java file (QtBattery.java)

import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.BatteryManager;

public class QtBattery {

    public static double getBatteryPercentage(Context context) {
        IntentFilter ifilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
        Intent batteryStatus = context.registerReceiver(null, ifilter);

        if (batteryStatus != null) {
            int level = batteryStatus.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);
            int scale = batteryStatus.getIntExtra(BatteryManager.EXTRA_SCALE, -1);

            if (level != -1 && scale != -1) {
                return ((level * 100.0)/ scale);
            }
        }
        return -1.0; // Return -1.0f if battery status cannot be retrieved
    }
}

A c++ method in a QWidget class that periodically is called to check the Android battery status.

    #ifdef ANDROID
        jdouble QtTest4::batteryStatus()
        {
            jdouble batteryLevel=-1.0;
            QJniObject activity = QNativeInterface::QAndroidApplication::context();
            if (activity.isValid())
            {
                QJniObject context = activity.callObjectMethod("getApplicationContext", "()Landroid/content/Context;");
                if (context.isValid())
                {
                    batteryLevel = context.callStaticMethod<jdouble>("com/home/QtTest4/QtBattery", "getBatteryPercentage");
                }
            }
            return batteryLevel;
        }
    #endif

The AndroidManifest.xml includes:

   <uses-permission android:name="android.permission.BATTERY_STATS"/>

The problem is the batteryLevel variable is always returned as zero (0.0).

I am looking for suggestions or ideas has to what is wrong.
Thanks.

[SMF-Qt]

@SMF-Qt

I have noticed problems with BroadcastReceiver on my application shut down see:

[https://forum.qt.io/topic/162708/running-a-profiled-app-on-x86_64-android-emulator-qt6.9.1/15]

Have I set up the "registerReceiver" correctly ?

[SMF-Qt]

@SMF-Qt

Having read some Qt documents I reduced th C++ code to:

    #ifdef ANDROID
        jdouble batteryStatus()
        {
            jdouble batteryLevel=-1.0;
            batteryLevel = QJniObject::callStaticMethod<jdouble>("com/home/QtTest4/QtBattery","getBatteryPercentage");
            return batteryLevel;
	}
    #endif

This did not help the return value is still 0.0.

[SMF-Qt]

@SMF-Qt

Discovered a possible problem:

When I run the app I get this logged in the QtCreator debugger:

app=com.home.QtTest4
W/default : java.lang.ClassNotFoundException: Didn't find class "com.home.QtTest4.QtBattery" on path: DexPathList[[zip file "/data/app/~~cyksSJNg5CvNsUTpniskXw==/com.home.QtTest4-DhBmss0nc93tjcVIRFtFdQ==/base.apk"],nativeLibraryDirectories=[/system/lib64, /system_ext/lib64]]

My AndroidManifest.xml file starts with:

<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.home.QtTest4" android:installLocation="auto" android:versionCode="115" android:versionName="QtTest4D">

AndroidManifest.xml and QtBattery.java locations:

/work/Qt-Android/QtTest4/android/AndroidManifest.xml
/work/Qt-Android/QtTest4/android/src/QtBattery.java

Invocation of Java method in my C++ file:

batteryLevel = QJniObject::callStaticMethod<jdouble>("com/home/QtTest4/QtBattery","getBatteryPercentage");

I have no clue has to what is wrong, any suggestions please.

[SMF-Qt]

@SMF-Qt

Found the solution:

changed the static method call in my C++ file to:

batteryLevel = QJniObject::callStaticMethod<jdouble>("QtBattery","getBatteryPercentage",QNativeInterface::QAndroidApplication::context());

And it now works.