icon notification doesn't appear

[kevinmohu]

Hi guys, i'm using flutter_local_notifications 1.4.4 for Schedule a notification to be shown daily at a specified time (even when my app is closed), it works good.

The fact is when I used my phone as emulator, the notification works well, the color image appears (Image1). But when I generate apk and install in my phone the notification icon doesn't appear (Image 2) you can see a small grey box instead. I try solution multiple ways solutions and I didn't get it. How can i do my apk show the icon in notification?

An aditional question, why AndroidInitializationSettings('app_icon'); doen't accept for example : assets/perfil3.png

I attatch my :
AndroidManifest.xml File:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.estilos">
        <uses-permission android:name="android.permission.INTERNET" />
        <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
        <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
        android:name="io.flutter.app.FlutterApplication"
        android:label="Alerta Temprana"
        android:icon="@mipmap/ic_launcher">
        <activity
            android:name=".MainActivity"
            android:launchMode="singleTop"
            android:theme="@style/LaunchTheme"
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
            android:hardwareAccelerated="true"
            android:windowSoftInputMode="adjustResize">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
        <receiver android:name="com.dexterous.flutterlocalnotifications.ScheduledNotificationReceiver" />
        <receiver android:name="com.dexterous.flutterlocalnotifications.ScheduledNotificationBootReceiver">
            <intent-filter>
                    <action android:name="android.intent.action.BOOT_COMPLETED"></action>
            </intent-filter>
        </receiver>
        <meta-data
            android:name="flutterEmbedding"
            android:value="2" />
    </application>
</manifest>

proguard-rules.pro

## Flutter wrapper
-keep class io.flutter.app.** { *; }
-keep class io.flutter.plugin.**  { *; }
-keep class io.flutter.util.**  { *; }
-keep class io.flutter.view.**  { *; }
-keep class io.flutter.**  { *; }
-keep class io.flutter.plugins.**  { *; }
-dontwarn io.flutter.embedding.**

## Gson rules
# Gson uses generic type information stored in a class file when working with fields. Proguard
# removes such information by default, so configure it to keep all of it.
-keepattributes Signature

# For using GSON @Expose annotation
-keepattributes *Annotation*

# Gson specific classes
-dontwarn sun.misc.**
#-keep class com.google.gson.stream.** { *; }

# Prevent proguard from stripping interface information from TypeAdapter, TypeAdapterFactory,
# JsonSerializer, JsonDeserializer instances (so they can be used in @JsonAdapter)
-keep class * implements com.google.gson.TypeAdapter
-keep class * implements com.google.gson.TypeAdapterFactory
-keep class * implements com.google.gson.JsonSerializer
-keep class * implements com.google.gson.JsonDeserializer

# Prevent R8 from leaving Data object members always null
-keepclassmembers,allowobfuscation class * {
  @com.google.gson.annotations.SerializedName <fields>;
}

## flutter_local_notification plugin rules
-keep class com.dexterous.** { *; }

buildgradle modification

buildTypes {
       release {
           signingConfig signingConfigs.release
           minifyEnabled true
           useProguard true

            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
       }
   }

my code and how initialize my code

import 'package:estilos/src/bloc/provider.dart';
import 'package:estilos/src/pages/splashScreeen_page.dart';
import 'package:estilos/src/routes/routes.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_localizations/flutter_localizations.dart';
import 'package:flutter_local_notifications/flutter_local_notifications.dart';

void main(){
  return runApp(MyApp());
}
 
class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =  FlutterLocalNotificationsPlugin();

  @override
  void initState() {
 
    super.initState();
    setupNotificationPlugin();
  }

  void setupNotificationPlugin() async{
    
    var initializationSettingsAndroid =  AndroidInitializationSettings('app_icon');
    var initializationSettingsIOS = IOSInitializationSettings(
        requestSoundPermission: false,
        requestBadgePermission: false,
        requestAlertPermission: false,
        onDidReceiveLocalNotification: onDidReceiveLocalNotification,
    );
    var initializationSettings = InitializationSettings(initializationSettingsAndroid, initializationSettingsIOS);
    await flutterLocalNotificationsPlugin.initialize(initializationSettings,onSelectNotification: onSelectNotification).then((init){
      setupNotification();
    });
  }


  Future onSelectNotification(String payload) async {
    if (payload != null) {
      debugPrint('notification payload: ' + payload);
    }
    await Navigator.push(context,MaterialPageRoute(builder: (context) => SplashScreen()),);
  }



  Future onDidReceiveLocalNotification(int id, String title, String body, String payload) async {
    // display a dialog with the notification details, tap ok to go to another page
    showDialog(
      context: context,
      builder: (BuildContext context) => AlertDialog(
        content: Text('Llenado de Cuestionario'),
        actions: <Widget>[
          FlatButton(
            onPressed: (){Navigator.of(context).pop();},
            child: Text('OK'))
        ],

      ),
    );
  }

  void setupNotification() async{
    var time = Time(18,30,0);
    var androidPlatformChannelSpecifics = AndroidNotificationDetails(
      'repeatDailyAtTime channel id',
      'repeatDailyAtTime channel name',
      'repeatDailyAtTime description');
    var iOSPlatformChannelSpecifics = IOSNotificationDetails();
    var platformChannelSpecifics = NotificationDetails(androidPlatformChannelSpecifics, iOSPlatformChannelSpecifics);
    await flutterLocalNotificationsPlugin.showDailyAtTime(
      0,
      'Registra tus síntomas',
      'Llenado de cuestionario',
      time,
      platformChannelSpecifics);
  }

  @override
  Widget build(BuildContext context) {
    return Provider(
      child: MaterialApp(
        debugShowCheckedModeBanner: false,
        title: 'Material App',
        localizationsDelegates: [
        GlobalMaterialLocalizations.delegate,
        GlobalWidgetsLocalizations.delegate,  
        GlobalCupertinoLocalizations.delegate,
      ],
      supportedLocales: [
        const Locale('en'), // English
        const Locale('es'), // español
        const Locale.fromSubtags(languageCode: 'zh'), // Chinese *See Advanced Locales below*
    ],
        initialRoute: 'splashScreen',
        routes:getApplicationRoutes(),
        theme: ThemeData(
          primaryColor: Colors.deepPurpleAccent,
        ),
      ),
    ); 
      
  }
}

and my res file pic where i add app_icon.png to compile code in order to it launch error

[MaikuB]

This is happening as you didn't follow all the steps covered in the readme. Please make sure you read and the follow the readme steps in full https://github.com/MaikuB/flutter_local_notifications/blob/master/flutter_local_notifications/README.md#release-configurations

[MaikuB]

Forgot to answer your other question on icons. Flutter itself can't display notifications so the purpose of this plugin is to work with the native notification APIs. These APIs will have certain requirements for them to work