Flutter, background fetch package not working, androidx incompatibility - flutter

Question

I wanted to make some operations while the app was not running, so I decided to use the background fetch package.I followed the android setup step by step
This is part of my pubspec.yaml
version: 1.0.0+1
environment:
sdk: ">=2.1.0 <3.0.0"
dependencies:
flutter:
sdk: flutter
google_maps_flutter: ^0.5.16
geolocator: ^5.1.1
flutter_local_notifications: ^0.7.1+1
shared_preferences: '0.5.6+3'
background_fetch: '^0.5.1'
This is part of my AndroidManifest.xml
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="firenzepuliziastrade.firenze_pulizia_strade">
<!-- io.flutter.app.FlutterApplication is an android.app.Application that
calls FlutterMain.startInitialization(this); in its onCreate method.
In most cases you can leave this as-is, but you if you want to provide
additional functionality it is fine to subclass or reimplement
FlutterApplication and put your custom class here. -->
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
<uses-permission android:name="android.permission.VIBRATE" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<application
tools:replace="android:label"
android:name="io.flutter.app.FlutterApplication"
android:label="Firenze Pulizia Strade"
android:icon="#mipmap/ic_launcher">
This is part of my app/build.gradle
android {
compileSdkVersion rootProject.ext.compileSdkVersion
defaultConfig {
// TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
applicationId "firenzepuliziastrade.firenze_pulizia_strade"
minSdkVersion 16
targetSdkVersion rootProject.ext.targetSdkVersion
versionCode flutterVersionCode.toInteger()
versionName flutterVersionName
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}
}
dependencies {
implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
testImplementation 'junit:junit:4.12'
androidTestImplementation 'androidx.test:runner:1.1.1'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
}
This is part of my android/build.gradle
buildscript {
ext.kotlin_version = '1.3.50'
ext {
compileSdkVersion = 28 // or higher
targetSdkVersion = 28 // or higher
appCompatVersion = "1.1.0" // or higher
}
repositories {
google()
jcenter()
}
dependencies {
classpath 'com.android.tools.build:gradle:3.5.0'
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
}
}
allprojects {
repositories {
google()
jcenter()
maven {
// [required] background_fetch
url "${project(':background_fetch').projectDir}/libs"
}
}
}
This is my gradle.properties
org.gradle.jvmargs=-Xmx1536M
android.enableR8=true
android.useAndroidX=true
android.enableJetifier=true
I tried even the additional step to enable the Headless mechanism even though I thought that it was not necessary since my flutter version is Flutter 1.12.13 and I created this project recently.
But all that said I could not make the app do some work while not running, it just worked while being in the background. So I thought that the reason was that I was launching the app in debug mode and I tried to launch it in release mode, but I got the following error:
Launching lib/main.dart on POT LX1 in release mode...
Running Gradle task 'assembleRelease'...
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':path_provider:verifyReleaseResources'.
> A failure occurred while executing com.android.build.gradle.internal.tasks.Workers$ActionFacade
> Android resource linking failed
/home/nik/.gradle/caches/transforms-2/files-2.1/0a271e99b6771ad4a84318244d532fb7/core-1.0.0/res/values/values.xml:57:5-88:25: AAPT: error: resource android:attr/fontVariationSettings not found.
/home/nik/.gradle/caches/transforms-2/files-2.1/0a271e99b6771ad4a84318244d532fb7/core-1.0.0/res/values/values.xml:57:5-88:25: AAPT: error: resource android:attr/ttcIndex not found.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
* Get more help at https://help.gradle.org
BUILD FAILED in 7s
The built failed likely due to AndroidX incompatibilities in a plugin. The tool is about to try using Jetfier to solve the incompatibility.
Building plugin background_fetch...
Running Gradle task 'assembleAarRelease'...
Finished with error: ProcessException: Permission denied
Command: /home/nik/Desktop/Pulizia_Strade/flutter/.pub-cache/hosted/pub.dartlang.org/background_fetch-0.5.6/android/gradlew -I=/home/nik/Desktop/Pulizia_Strade/flutter/packages/flutter_tools/gradle/aar_init_script.gradle -Pflutter-root=/home/nik/Desktop/Pulizia_Strade/flutter -Poutput-dir=/home/nik/Desktop/Pulizia_Strade/firenze_pulizia_strade/build/app -Pis-plugin=true -Ptarget-platform=android-arm,android-arm64,android-x64 assembleAarRelease
I tried to create a new flutter project, specifying androidx, but it did notwork, I got the same error. Can someone help me, I really do not know what to do at this point...

Answer 1

It seems that your app is not compatible with AndroidX. So far you've done some troubleshooting but didn't get to make it work. Try to double check the AndroidX Migration Guide if you haven't missed anything.
So far, you've already enabled the Jetifier by adding the following lines to [project_folder]/android/app/gradle.properties
android.useAndroidX=true
android.enableJetifier=true
Now try to enable multidex by adding this line in the defaultConfig of [project_folder]/app/build.gradle
defaultConfig {
...
multiDexEnabled true
}
Then upgrade gradle dependency in the [project_folder]/android/build.gradle file:
classpath 'com.android.tools.build:gradle:4.1.0'
Latest version used in flutter as specified here.
Next, make sure that all your packages in the pubspec.yaml are of the latest version.
Lastly, run flutter clean and rebuild your project.