CODEWITHSUNDEEP
androidqtandroid-manifest
rightaway717
rightaway717

Reputation: 2831

What does "android.app.background_running" in AndroidManifest.xml mean?

Basically, the question is in the title.

Example:

<?xml version="1.0"?>
<manifest package="org.example.test" xmlns:android="http://schemas.android.com/apk/res/android" android:versionName="0.1" android:versionCode="1" android:installLocation="auto">
    <application android:hardwareAccelerated="true" android:name="org.qtproject.qt5.android.bindings.QtApplication" android:label="@string/app_name" android:icon="@drawable/icon">
        <activity android:configChanges="orientation|uiMode|screenLayout|screenSize|smallestScreenSize|locale|fontScale|keyboard|keyboardHidden|navigation" android:name="org.qtproject.qt5.android.bindings.StartActivity" android:label="@string/app_name" android:screenOrientation="sensorLandscape" android:launchMode="singleTop" android:theme="@android:style/Theme.NoTitleBar.Fullscreen">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
            <!-- 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="true"/>
        </activity>
    </application>
    <uses-sdk android:minSdkVersion="16" android:targetSdkVersion="19"/>
    <supports-screens android:largeScreens="true" android:normalScreens="true" android:anyDensity="true" android:smallScreens="true"/>
</manifest>

It is used in QT apps for Android, but I thought it has nothing to do with QT since it is in manifest. Am I wrong?

Upvotes: 2

Views: 1730

Answers (2)

rightaway717
rightaway717

Reputation: 2831

Since this option has really nothing to do with Android API as I thought before, I started digging into QT sources what that means.

Setting this option will export QT_BLOCK_EVENT_LOOPS_WHEN_SUSPENDED environment variable, which will be checked by QT native code and will stop event dispatcher (no QCoreApplication::processEvents will be called since then) for QT part of the app when the main Activity was stopped or paused by onStop() and onPause() methods. So that is what means "freezing" the event loop.

I don't know of all cautions one should be aware of, but I will update my answer as soon as I find it out.

Upvotes: 2

Rohit5k2
Rohit5k2

Reputation: 18112

After long search this is what I found

What does this option do?

Setting android.app.background_running to true means don’t freeze the Qt main loop, but you must make sure you don’t draw anything when the application is backgrounded.

This SO answer says how can we change its default value QT 5 android, Change background_running value to True

Upvotes: 1

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