title: java.lang.NoClassDefFoundError: Failed resolution of: Lcom/google/android/gms/common/R$string;
body: <p>I tried out many things, but it does not solve my problem. </p>
  
  <p>Full Error Code (kompletter Error Code):</p>
  
  <pre><code>05-16 09:59:53.428 25010-25010/main.faseflex.de.fgnapp E/AndroidRuntime: FATAL EXCEPTION: main
  Process: main.faseflex.de.fgnapp, PID: 25010
  java.lang.NoClassDefFoundError: Failed resolution of: Lcom/google/android/gms/common/R$string;
      at com.google.android.gms.common.internal.StringResourceValueReader.&lt;init&gt;(Unknown Source:14)
      at com.google.firebase.FirebaseOptions.fromResource(Unknown Source:2)
      at com.google.firebase.FirebaseApp.initializeApp(Unknown Source:19)
      at com.google.firebase.provider.FirebaseInitProvider.onCreate(Unknown Source:4)
      at android.content.ContentProvider.attachInfo(ContentProvider.java:1925)
      at android.content.ContentProvider.attachInfo(ContentProvider.java:1900)
      at com.google.firebase.provider.FirebaseInitProvider.attachInfo(Unknown Source:23)
      at android.app.ActivityThread.installProvider(ActivityThread.java:6578)
      at android.app.ActivityThread.installContentProviders(ActivityThread.java:6133)
      at android.app.ActivityThread.handleBindApplication(ActivityThread.java:6043)
      at android.app.ActivityThread.-wrap1(Unknown Source:0)
      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1764)
      at android.os.Handler.dispatchMessage(Handler.java:105)
      at android.os.Looper.loop(Looper.java:164)
      at android.app.ActivityThread.main(ActivityThread.java:6944)
      at java.lang.reflect.Method.invoke(Native Method)
      at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:327)
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1374)
   Caused by: java.lang.ClassNotFoundException: Didn't find class "com.google.android.gms.common.R$string" on path: DexPathList[[zip file "/data/app/main.faseflex.de.fgnapp-C4iBOV7sIO2cNc4pfCATmA==/base.apk"],nativeLibraryDirectories=[/data/app/main.faseflex.de.fgnapp-C4iBOV7sIO2cNc4pfCATmA==/lib/arm64, /system/lib64, /system/vendor/lib64]]
      at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:93)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:379)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
      at com.google.android.gms.common.internal.StringResourceValueReader.&lt;init&gt;(Unknown Source:14) 
      at com.google.firebase.FirebaseOptions.fromResource(Unknown Source:2) 
      at com.google.firebase.FirebaseApp.initializeApp(Unknown Source:19) 
      at com.google.firebase.provider.FirebaseInitProvider.onCreate(Unknown Source:4) 
      at android.content.ContentProvider.attachInfo(ContentProvider.java:1925) 
      at android.content.ContentProvider.attachInfo(ContentProvider.java:1900) 
      at com.google.firebase.provider.FirebaseInitProvider.attachInfo(Unknown Source:23) 
      at android.app.ActivityThread.installProvider(ActivityThread.java:6578) 
      at android.app.ActivityThread.installContentProviders(ActivityThread.java:6133) 
      at android.app.ActivityThread.handleBindApplication(ActivityThread.java:6043) 
      at android.app.ActivityThread.-wrap1(Unknown Source:0) 
      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1764) 
      at android.os.Handler.dispatchMessage(Handler.java:105) 
      at android.os.Looper.loop(Looper.java:164) 
      at android.app.ActivityThread.main(ActivityThread.java:6944) 
      at java.lang.reflect.Method.invoke(Native Method) 
      at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:327) 
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1374) 
  </code></pre>
  
  <p>build.gradle app:</p>
  
  <pre><code>    apply plugin: 'com.android.application'
  
  android {
      compileSdkVersion 25
      //buildToolsVersion "25.0.2"
      defaultConfig {
          applicationId "main.faseflex.de.fgnapp"
          minSdkVersion 21
          targetSdkVersion 25
          multiDexEnabled true
          dexOptions {
              preDexLibraries true
          }
          versionCode 1
          versionName "0.98.41"
          testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
          vectorDrawables.useSupportLibrary = true
      }
      buildTypes {
          release {
              minifyEnabled false
              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
              multiDexKeepFile file('multidex-config.txt')
          }
  
      }
      productFlavors {
      }
  }
  
  dependencies {
      implementation 'com.android.support:support-v4:25.4.0'
      implementation 'com.android.support:support-vector-drawable:25.4.0'
      implementation fileTree(include: ['*.jar'], dir: 'libs')
      androidTestImplementation('com.android.support.test.espresso:espresso-core:2.2.2', {
          exclude group: 'com.android.support', module: 'support-annotations'
      })
      implementation 'com.google.firebase:firebase-core:15.0.2'
      implementation 'com.google.firebase:firebase-messaging:15.0.2'
      implementation 'com.google.firebase:firebase-database:15.0.1'
      implementation 'com.google.firebase:firebase-auth:15.1.0'
      implementation 'com.android.support:appcompat-v7:25.4.0'
      implementation 'com.android.support:design:25.4.0'
      implementation 'com.android.support:preference-v7:25.4.0'
      implementation 'com.android.support.constraint:constraint-layout:1.1.0'
      implementation 'com.github.SHashank02051997:FancyToast-Android:0.1.3'
      implementation 'com.android.support:multidex:1.0.3'
      implementation 'com.google.android.gms:play-services-auth:15.0.1'
      testImplementation 'junit:junit:4.12'
  }
  apply plugin: 'com.google.gms.google-services'
  
  configurations.all {
      resolutionStrategy.eachDependency { DependencyResolveDetails details -&gt;
          def requested = details.requested
          if (requested.group == 'com.android.support') {
              if (!requested.name.startsWith("multidex")) {
                  details.useVersion '25.3.0'
              }
          }
      }
  }
  </code></pre>
  
  <p>build.gradle project:</p>
  
  <pre><code>    // Top-level build file where you can add configuration options common to all sub-projects/modules.
  
  buildscript {
      repositories {
          jcenter()
          google()
      }
      dependencies {
          classpath 'com.android.tools.build:gradle:3.1.2'
          classpath 'com.google.gms:google-services:3.2.0'
  
          // NOTE: Do not place your application dependencies here; they belong
          // in the individual module build.gradle files
      }
  }
  
  allprojects {
      repositories {
          jcenter()
          google()
          maven {
              url "https://jitpack.io"
          }
          maven {
              url "https://maven.google.com"
          }
      }
  }
  
  task clean(type: Delete) {
      delete rootProject.buildDir
  }
  </code></pre>
  
  <p>AndroidManifest.xml:</p>
  
  <pre><code>&lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      package="main.faseflex.de.fgnapp"
      tools:node="replace"&gt;
  
      &lt;supports-screens
          android:anyDensity="true"
          android:compatibleWidthLimitDp="50"
          android:largeScreens="true"
          android:normalScreens="true"
          android:resizeable="false"
          android:smallScreens="false"
          android:xlargeScreens="false" /&gt;
  
      &lt;uses-permission android:name="android.permission.INTERNET" /&gt;
  
      &lt;application
          android:allowBackup="true"
          android:icon="@mipmap/fgn_icon"
          android:label="@string/app_name"
          android:resizeableActivity="false"
          android:roundIcon="@mipmap/fgn_icon"
          android:supportsRtl="true"
          android:theme="@style/AppTheme"&gt;
  
          ------------------------------------------------
          MAIN ACTIVITY
          ------------------------------------------------
          &lt;activity
              android:name=".FGNmainActivity"
              android:label="FGN-App"
              android:screenOrientation="portrait"&gt;
              &lt;intent-filter&gt;
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
  
                  &lt;category android:name="android.intent.category.DEFAULT" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
          ------------------------------------------------
          STUNDENPLAN
          ------------------------------------------------
          &lt;activity
              android:name=".activity_timetable"
              android:label="FGN-App | Stundenplan"
              android:parentActivityName=".FGNmainActivity"
              android:screenOrientation="portrait"
              android:theme="@style/AppTheme"&gt;
              &lt;intent-filter&gt;
                  &lt;category android:name="android.intent.category.APP_BROWSER" /&gt;
  
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
          ------------------------------------------------
          ESSENSBESTELLUNG
          ------------------------------------------------
          &lt;activity
              android:name=".activity_food"
              android:label="FGN-App | Essenplan"
              android:parentActivityName=".FGNmainActivity"
              android:theme="@style/AppTheme"&gt;
              &lt;intent-filter&gt;
                  &lt;category android:name="android.intent.category.APP_BROWSER" /&gt;
  
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
          ------------------------------------------------
          MDV
          ------------------------------------------------
          &lt;activity
              android:name=".activity_mdv"
              android:label="FGN-App | Verkehrsverbund"
              android:parentActivityName=".FGNmainActivity"
              android:screenOrientation="portrait"
              android:theme="@style/AppTheme"&gt;
              &lt;intent-filter&gt;
                  &lt;category android:name="android.intent.category.APP_BROWSER" /&gt;
  
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
          ------------------------------------------------
          DOKUMENTE
          ------------------------------------------------
          &lt;activity
              android:name=".activity_documents"
              android:label="FGN-App | Dokumente"
              android:parentActivityName=".FGNmainActivity"
              android:screenOrientation="portrait"
              android:theme="@style/AppTheme"&gt;
              &lt;intent-filter&gt;
                  &lt;category android:name="android.intent.category.APP_BROWSER" /&gt;
  
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
          ------------------------------------------------
          NEWS
          ------------------------------------------------
          &lt;activity
              android:name=".activity_news"
              android:label="FGN-App | News"
              android:parentActivityName=".FGNmainActivity"
              android:screenOrientation="portrait"
              android:theme="@style/AppTheme"&gt;
              &lt;intent-filter&gt;
                  &lt;category android:name="android.intent.category.APP_BROWSER" /&gt;
  
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
          ------------------------------------------------
          LEHRER
          ------------------------------------------------
          &lt;activity
              android:name=".activity_teachers"
              android:label="FGN-App | Lehrer"
              android:parentActivityName=".FGNmainActivity"
              android:screenOrientation="portrait"
              android:theme="@style/AppTheme"&gt;
              &lt;intent-filter&gt;
                  &lt;category android:name="android.intent.category.APP_BROWSER" /&gt;
  
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
          ------------------------------------------------
          MOODLE
          ------------------------------------------------
          &lt;activity
              android:name=".activity_moodle"
              android:label="FGN-App | Moodle"
              android:parentActivityName=".FGNmainActivity"
              android:screenOrientation="portrait"
              android:theme="@style/AppTheme"&gt;
              &lt;intent-filter&gt;
                  &lt;category android:name="android.intent.category.APP_BROWSER" /&gt;
  
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
          ------------------------------------------------
          OFFICE 365
          ------------------------------------------------
          &lt;activity
              android:name=".activity_office"
              android:label="FGN-App | Office 365"
              android:parentActivityName=".FGNmainActivity"
              android:screenOrientation="portrait"
              android:theme="@style/AppTheme"&gt;
              &lt;intent-filter&gt;
                  &lt;category android:name="android.intent.category.APP_BROWSER" /&gt;
  
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
          ------------------------------------------------
          KONTAKT
          ------------------------------------------------
          &lt;activity
              android:name=".activity_contact"
              android:label="FGN-App | Kontakt"
              android:parentActivityName=".FGNmainActivity"
              android:screenOrientation="portrait"
              android:theme="@style/AppTheme"&gt;
              &lt;intent-filter&gt;
                  &lt;category android:name="android.intent.category.APP_BROWSER" /&gt;
  
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
          ------------------------------------------------
          TERMINE
          ------------------------------------------------
          &lt;activity
              android:name=".activity_termine"
              android:label="FGN-App | Termine"
              android:parentActivityName=".FGNmainActivity"
              android:screenOrientation="portrait"
              android:theme="@style/AppTheme"&gt;
              &lt;intent-filter&gt;
                  &lt;category android:name="android.intent.category.APP_BROWSER" /&gt;
  
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
          ------------------------------------------------
          MITTAGSBAND
          ------------------------------------------------
          &lt;activity
              android:name=".activity_mittagsband"
              android:label="FGN-App | Mittagsband"
              android:parentActivityName=".FGNmainActivity"
              android:screenOrientation="portrait"
              android:theme="@style/AppTheme"&gt;
              &lt;intent-filter&gt;
                  &lt;category android:name="android.intent.category.APP_BROWSER" /&gt;
  
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
          ------------------------------------------------
          FEEDBACK
          ------------------------------------------------
          &lt;activity
              android:name=".activity_menu_feedback"
              android:label="FGN-App | Feedback"
              android:parentActivityName=".SettingsActivity"
              android:screenOrientation="portrait"
              android:theme="@style/AppTheme"&gt;
              &lt;intent-filter&gt;
                  &lt;category android:name="android.intent.category.DEFAULT" /&gt;
  
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
          ------------------------------------------------
          IMPRESSUM
          ------------------------------------------------
          &lt;activity
              android:name=".activity_menu_impressum"
              android:label="FGN-App | Impressum"
              android:parentActivityName=".FGNmainActivity"
              android:screenOrientation="portrait"
              android:theme="@style/AppTheme"&gt;
              &lt;intent-filter&gt;
                  &lt;category android:name="android.intent.category.DEFAULT" /&gt;
  
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
          ------------------------------------------------
          FIREBASE
          ------------------------------------------------
          &lt;service android:name=".MyFirebaseMessagingService"&gt;
              &lt;intent-filter&gt;
                  &lt;action android:name="com.google.firebase.MESSAGING_EVENT" /&gt;
              &lt;/intent-filter&gt;
          &lt;/service&gt;
          &lt;service android:name=".FirebaseIDService"&gt;
              &lt;intent-filter&gt;
                  &lt;action android:name="com.google.firebase.INSTANCE_ID_EVENT" /&gt;
              &lt;/intent-filter&gt;
          &lt;/service&gt;
          &lt;service android:name=".MyInstanceIDListenerService"&gt;
              &lt;intent-filter&gt;
                  &lt;action android:name="com.google.firebase.INSTANCE_ID_EVENT" /&gt;
              &lt;/intent-filter&gt;
          &lt;/service&gt;
          ------------------------------------------------
          EINSTELLUNGEN
          ------------------------------------------------
          &lt;activity
              android:name=".SettingsActivity"
              android:label="FGN-App | Einstellungen"
              android:parentActivityName=".FGNmainActivity"&gt;
              &lt;meta-data
                  android:name="android.support.PARENT_ACTIVITY"
                  android:value="main.faseflex.de.fgnapp.FGNmainActivity" /&gt;
          &lt;/activity&gt;
          ------------------------------------------------
          SPLASH SCREEN
          ------------------------------------------------
          &lt;activity
              android:name=".SplashActivity"
              android:screenOrientation="portrait"&gt;
              &lt;intent-filter&gt;
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
  
                  &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
          ------------------------------------------------
          CHANGELOG
          ------------------------------------------------
          &lt;activity
              android:name=".ChangelogActivity"
              android:label="FGN-App | Changelog"
              android:parentActivityName=".SettingsActivity"&gt;&lt;/activity&gt;
      &lt;/application&gt;
  
  
  
  &lt;/manifest&gt;
  </code></pre>
  
  <p>I know what the NoClassDefFoundError does, but I did not find the problem. Ask if you need more files for solving the problem. </p>