Unable to setup Firebase Database in Android

Question

I recently started working with Google Firebase for Android. I had some trouble with it. But I tried to setup the Firebase manually now I am getting a new error. I am sure that it has to do something with the gradle.

My build.gradle(app):

apply plugin: 'com.android.application'
//apply plugin: 'com.google.gms.google-services'

android {
    compileSdkVersion 23
    buildToolsVersion "24.0.1"
    defaultConfig {
        applicationId "com.example.nirmal.ilistensinch"
        minSdkVersion 16
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        multiDexEnabled true
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'

        }
    }
}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    /*androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })*/
    compile 'com.google.firebase:firebase-database:10.0.1'
    compile 'com.android.support:appcompat-v7:23.0.0'
    compile 'com.android.support:design:23.0.0'
    compile 'com.android.support:support-v4:23.0.0'
    compile 'com.android.support:cardview-v7:23.0.1'
    compile 'com.android.support:recyclerview-v7:23.0.1'
    testCompile 'junit:junit:4.12'
    compile files('/media/win/Android Apps/IlistenSinch/sinch-android-rtc-3.9.10.jar')
}

My build.gradle(project):

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.2.3'
        classpath 'com.google.gms:google-services:3.0.0'
//        apply plugin: 'com.google.gms.google-services'
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

but when I run the code I am getting the following error

 Caused by: java.lang.IllegalStateException: Default FirebaseApp is not initialized in this process com.example.nirmal.ilistensinch. Make sure to call FirebaseApp.initializeApp(Context) first.
                                                                                     at com.google.firebase.FirebaseApp.getInstance(Unknown Source)
                                                                                     at com.google.firebase.database.FirebaseDatabase.getInstance(Unknown Source)
                                                                                     at com.example.nirmal.ilistensinch.SinchLoginActivity.onCreate(SinchLoginActivity.java:46)
                                                                                     at android.app.Activity.performCreate(Activity.java:5264)
                                                                                     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1088)
                                                                                     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2302)
                                                                                     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390) 
                                                                                     at android.app.ActivityThread.access$800(ActivityThread.java:151) 
                                                                                     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1321) 
                                                                                     at android.os.Handler.dispatchMessage(Handler.java:110) 
                                                                                     at android.os.Looper.loop(Looper.java:193) 
                                                                                     at android.app.ActivityThread.main(ActivityThread.java:5292) 
                                                                                     at java.lang.reflect.Method.invokeNative(Native Method) 
                                                                                     at java.lang.reflect.Method.invoke(Method.java:515) 
                                                                                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:824) 
                                                                                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:640) 
                                                                                     at dalvik.system.NativeStart.main(Native Method) 

If you notice my build.gradle(app) you can see that I have commented apply plugin: 'com.google.gms.google-services'

If I take out that comment I am getting this error:

Error:Execution failed for task ':app:transformClassesWithJarMergingForDebug'.
> com.android.build.api.transform.TransformException: java.util.zip.ZipException: duplicate entry: com/google/android/gms/common/api/zza.class

Any idea on how to solve this problem?

Answer 1

Put the apply plugin: 'com.google.gms.google-services' at the bottom of your app's build.gradle

...
    testCompile 'junit:junit:4.12'
    compile files('/media/win/Android Apps/IlistenSinch/sinch-android-rtc-3.9.10.jar')
}
apply plugin: 'com.google.gms.google-services'

You should read this official Firebase setup guide for Android