Bdtjtk

So I tried adding a user to a firebase group to be able to send data notification to multiple user on a simple app that show the notification when it receives it.

My problem is that following the firebase documentation I tried adding the following line to my mainactivity.java

FirebaseMessaging.getInstance().subscribeToTopic("weather")

But android studio told me that the .getInstance couldn't be called/"Cannot resolve symbol 'getInstance'é it so I don't know what to do to make it work

edit:

The app build.gradle:

apply plugin: 'com.android.application'

apply plugin: 'com.google.gms.google-services'



android {

    compileSdkVersion 28

    defaultConfig {

        applicationId "com.shayru.myapplication"

        minSdkVersion 21

        targetSdkVersion 28

        versionCode 1

        versionName "1.0"

        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"

    }

    buildTypes {

        release {

            minifyEnabled false

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

        }

    }

}



dependencies {

    implementation fileTree(dir: 'libs', include: ['*.jar'])

    implementation 'com.android.support:appcompat-v7:28.0.0'

    implementation 'com.android.support.constraint:constraint-layout:1.1.3'

    testImplementation 'junit:junit:4.12'

    androidTestImplementation 'com.android.support.test:runner:1.0.2'

    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'

    implementation 'com.google.firebase:firebase-messaging:17.3.4'

    implementation 'com.google.firebase:firebase-core:16.0.6'

}

The Project build.gradle :

// Top-level build file where you can add configuration options common to all sub-projects/modules.



buildscript {



    repositories {

        google()

        jcenter()

    }

    dependencies {

        classpath 'com.android.tools.build:gradle:3.2.1'

        classpath 'com.google.gms:google-services:4.2.0'



        // NOTE: Do not place your application dependencies here; they belong

        // in the individual module build.gradle files

    }

}



allprojects {

    repositories {

        google()

        jcenter()

    }

}



task clean(type: Delete) {

    delete rootProject.buildDir

}

and if needed this is what the mainactivity does :

package com.shayru.myapplication;



import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import com.google.firebase.messaging.FirebaseMessaging;





public class MainActivity extends AppCompatActivity {



    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

    }

    FirebaseMessaging.getInstance().subscribeToTopic("News");





}

The problem is not with Firebase, rather its with your code. Subscribe to the topic in your onCreate() method, not outside a method.

@Override

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

    FirebaseMessaging.getInstance().subscribeToTopic("News");

}