Cannot resolve symbol 'MultiDex'

Question

I'm trying to enable MultiDex. I added multiDexEnabled true and compile 'com.android.support:multidex:1.0.3' to build.gradle. I made a java file

public class ApplicationClass extends Application {
    @Override
    protected void attachBaseContext(Context base) {
        super.attachBaseContext(base);
        MultiDex.install(this);  // <----------
    }
}

and added android:name=".ApplicationClass" to manifest file.

But in the java file, in MultiDex.install(this); the MultiDex part is red and it says Cannot resolve symbol 'MultiDex'. And gradle sync fails. I also tried adding android:name="android.support.multidex.MultiDexApplication" to manifest, instead of creating the java file and extending application class. It didn't work either. The part MultiDexApplication is red and it says unresolved class 'MultiDexApplication'

I think there is something wrong with the android support library in my system. Multidex is from this library. Also when I change any of 'com.android.support:appcompat-v7:26.+' (to the specific version 26.0.1 as suggested by Android Studio) or 'com.android.support.constraint:constraint-layout:1.0.2' (to the newer version 1.1.2), gradle sync fails.

I looked into <SDK>/extras directory. And I see there are three different support directories. Not sure if this has something to do with the problem.

build.gradle

apply plugin: 'com.android.application'

android {
    compileSdkVersion 26
    buildToolsVersion "26.0.1"
    defaultConfig {
        applicationId "com.example.vvaezian.multilingovocabularypractice"
        minSdkVersion 15
        targetSdkVersion 26
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        multiDexEnabled true    <--- added ---
    }
    buildTypes {
        debug {
            buildConfigField 'String', "ApiKey", MultiLingo_ApiKey
        }
        release {
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
            buildConfigField 'String', "ApiKey", MultiLingo_ApiKey
        }
    }

    packagingOptions {
        exclude 'project.properties'
        exclude 'META-INF/INDEX.LIST'
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    androidTestImplementation('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    implementation 'com.android.support:appcompat-v7:26.+'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    implementation 'com.mcxiaoke.volley:library:1.0.19'
    testImplementation 'junit:junit:4.12'

    implementation 'com.google.code.gson:gson:2.8.2'
    implementation 'com.squareup.retrofit2:retrofit:2.3.0'
    implementation 'com.squareup.retrofit2:converter-gson:2.3.0'

    implementation 'com.google.code.gson:gson:2.8.2'
    implementation 'com.squareup.retrofit2:converter-gson:2.3.0'
    implementation 'com.squareup.okhttp3:logging-interceptor:3.4.1'
    implementation 'com.squareup.okhttp3:okhttp:3.8.0'

    implementation('com.google.cloud:google-cloud-translate:1.3.1') {
        exclude group: 'org.apache.httpcomponents'
        exclude group: 'org.json', module: 'json'
    }
    annotationProcessor 'com.google.cloud:google-cloud-translate:1.3.1'
    compile 'com.android.support:multidex:1.0.3'  // <----- added ----
    // using 'implementation' instead of 'compile' didn't resolve the issue
}

Also the log file does not say why the gradle sync fails. There is only one line that says Too many events posted ...

2018-08-01 13:56:54,922 [e-1024-b01]   INFO - e.project.sync.GradleSyncState - Started sync with Gradle for project 'MultiLingoVocabularyPractice'. 
2018-08-01 13:56:54,924 [e-1024-b01]   INFO - idea.project.IndexingSuspender - Consuming IndexingSuspender activation event: SYNC_STARTED 
2018-08-01 13:56:54,924 [e-1024-b01]   INFO - idea.project.IndexingSuspender - Starting batch update for project: Project '/local-scratch/vvaezian/AndroidStudioProjects/MultiLingoVocabularyPractice' MultiLingoVocabularyPractice 
2018-08-01 13:56:54,934 [hread 1914]   INFO - s.plugins.gradle.GradleManager - Instructing gradle to use java from /local-scratch/vvaezian/android-studio/jre 
2018-08-01 13:56:54,935 [hread 1914]   INFO - s.plugins.gradle.GradleManager - Instructing gradle to use java from /local-scratch/vvaezian/android-studio/jre 
2018-08-01 13:56:54,943 [hread 1914]   INFO - xecution.GradleExecutionHelper - Passing command-line args to Gradle Tooling API: -Didea.version=3.1 -Djava.awt.headless=true -Pandroid.injected.build.model.only=true -Pandroid.injected.build.model.only.advanced=true -Pandroid.injected.invoked.from.ide=true -Pandroid.injected.build.model.only.versioned=3 -Pandroid.injected.studio.version=3.1.3.0 -Pandroid.builder.sdkDownload=false --init-script /tmp/ijinit.gradle 
2018-08-01 13:56:57,640 [hread 1916]   INFO - agnostic.FrequentEventDetector - Too many events posted, #7. Event: java.awt.event.InvocationEvent[INVOCATION_DEFAULT,runnable=LaterInvocator.FlushQueue,notifier=null,catchExceptions=false,when=1533157017640] on sun.awt.X11.XToolkit@5b185819 
2018-08-01 13:56:57,676 [hread 1914]   INFO - e.project.sync.GradleSyncState - Started setup of project 'MultiLingoVocabularyPractice'. 
2018-08-01 13:56:57,677 [e-1024-b01]   INFO - idea.project.IndexingSuspender - Consuming IndexingSuspender activation event: SETUP_STARTED 
2018-08-01 13:56:57,789 [hread 1916]   INFO - idea.project.IndexingSuspender - Indexing suspended (context: Project Setup) 
2018-08-01 13:56:57,995 [e-1024-b01]   INFO - ule.android.SdkModuleSetupStep - Set Android SDK 'Android API 26 Platform (1)' (/local-scratch/vvaezian/SDK) to module 'app' 
2018-08-01 13:56:58,005 [hread 1917]   INFO - s.RepoProgressIndicatorAdapter - Parsing /local-scratch/vvaezian/SDK/build-tools/26.0.1/package.xml 
2018-08-01 13:56:58,009 [hread 1917]   INFO - s.RepoProgressIndicatorAdapter - Parsing /local-scratch/vvaezian/SDK/build-tools/27.0.3/package.xml 
2018-08-01 13:56:58,012 [hread 1917]   INFO - s.RepoProgressIndicatorAdapter - Parsing /local-scratch/vvaezian/SDK/emulator/package.xml 
2018-08-01 13:56:58,016 [hread 1917]   INFO - s.RepoProgressIndicatorAdapter - Parsing /local-scratch/vvaezian/SDK/extras/android/m2repository/package.xml 
2018-08-01 13:56:58,020 [hread 1917]   INFO - s.RepoProgressIndicatorAdapter - Parsing /local-scratch/vvaezian/SDK/extras/google/m2repository/package.xml 
2018-08-01 13:56:58,024 [hread 1917]   INFO - s.RepoProgressIndicatorAdapter - Parsing /local-scratch/vvaezian/SDK/extras/m2repository/com/android/support/constraint/constraint-layout-solver/1.0.2/package.xml 
2018-08-01 13:56:58,028 [hread 1917]   INFO - s.RepoProgressIndicatorAdapter - Parsing /local-scratch/vvaezian/SDK/extras/m2repository/com/android/support/constraint/constraint-layout/1.0.2/package.xml 
2018-08-01 13:56:58,032 [hread 1917]   INFO - s.RepoProgressIndicatorAdapter - Parsing /local-scratch/vvaezian/SDK/patcher/v4/package.xml 
2018-08-01 13:56:58,035 [hread 1917]   INFO - s.RepoProgressIndicatorAdapter - Parsing /local-scratch/vvaezian/SDK/platform-tools/package.xml 
2018-08-01 13:56:58,039 [hread 1917]   INFO - s.RepoProgressIndicatorAdapter - Parsing /local-scratch/vvaezian/SDK/platforms/android-23/package.xml 
2018-08-01 13:56:58,042 [hread 1917]   INFO - s.RepoProgressIndicatorAdapter - Parsing /local-scratch/vvaezian/SDK/platforms/android-24/package.xml 
2018-08-01 13:56:58,045 [hread 1917]   INFO - s.RepoProgressIndicatorAdapter - Parsing /local-scratch/vvaezian/SDK/platforms/android-25/package.xml 
2018-08-01 13:56:58,049 [hread 1917]   INFO - s.RepoProgressIndicatorAdapter - Parsing /local-scratch/vvaezian/SDK/platforms/android-26/package.xml 
2018-08-01 13:56:58,053 [hread 1917]   INFO - s.RepoProgressIndicatorAdapter - Parsing /local-scratch/vvaezian/SDK/sources/android-26/package.xml 
2018-08-01 13:56:58,056 [hread 1917]   INFO - s.RepoProgressIndicatorAdapter - Parsing /local-scratch/vvaezian/SDK/system-images/android-24/google_apis_playstore/x86/package.xml 
2018-08-01 13:56:58,060 [hread 1917]   INFO - s.RepoProgressIndicatorAdapter - Parsing /local-scratch/vvaezian/SDK/system-images/android-26/google_apis/x86/package.xml 
2018-08-01 13:56:58,063 [hread 1917]   INFO - s.RepoProgressIndicatorAdapter - Parsing /local-scratch/vvaezian/SDK/tools/package.xml 
2018-08-01 13:56:58,118 [hread 1914]   INFO - e.project.sync.GradleSyncState - Gradle sync failed (3s 196ms) 
2018-08-01 13:56:58,120 [e-1024-b01]   INFO - idea.project.IndexingSuspender - Consuming IndexingSuspender deactivation event: SYNC_FINISHED 
2018-08-01 13:56:58,120 [e-1024-b01]   INFO - idea.project.IndexingSuspender - Finishing batch update for project: Project '/local-scratch/vvaezian/AndroidStudioProjects/MultiLingoVocabularyPractice' MultiLingoVocabularyPractice 
2018-08-01 13:56:58,150 [e-1024-b01]   INFO - pl.ProjectRootManagerComponent - project roots have changed 
2018-08-01 13:56:58,169 [hread 1916]   INFO - idea.project.IndexingSuspender - Indexing released (context: Project Setup) 
2018-08-01 13:56:58,199 [hread 1916]   INFO - .diagnostic.PerformanceWatcher - Pushing properties took 2ms; general responsiveness: ok; EDT responsiveness: ok 
2018-08-01 13:56:58,254 [hread 1916]   INFO - .diagnostic.PerformanceWatcher - Indexable file iteration took 55ms; general responsiveness: ok; EDT responsiveness: ok 
2018-08-01 13:56:58,303 [hread 1916]   INFO -       #com.jetbrains.cidr.lang - Clearing symbols finished in 0 s. 
2018-08-01 13:56:58,304 [hread 1916]   INFO -       #com.jetbrains.cidr.lang - Building symbols in FAST mode, 0 source files from total 0 project files 
2018-08-01 13:56:58,305 [hread 1916]   INFO -       #com.jetbrains.cidr.lang - Loading Module Maps finished in 0 s. 
2018-08-01 13:56:58,305 [hread 1916]   INFO -       #com.jetbrains.cidr.lang - Saving Module Maps finished in 0 s. 
2018-08-01 13:56:58,305 [hread 1916]   INFO -       #com.jetbrains.cidr.lang - Saving Module Maps finished in 0 s. 
2018-08-01 13:56:58,305 [hread 1916]   INFO -       #com.jetbrains.cidr.lang - Loaded 0 tables for 0 files (0 project files) 
2018-08-01 13:56:58,305 [hread 1916]   INFO -       #com.jetbrains.cidr.lang - Building symbols for 0 source files 
2018-08-01 13:56:58,306 [hread 1916]   INFO -       #com.jetbrains.cidr.lang - Building symbols for 0 unused headers 
2018-08-01 13:56:58,307 [hread 1916]   INFO -       #com.jetbrains.cidr.lang - Building symbols finished in 0 s. 
2018-08-01 13:56:58,307 [hread 1916]   INFO -       #com.jetbrains.cidr.lang - Saving modified symbols for 0 files (0 tables of total 0) 
2018-08-01 13:56:58,307 [hread 1916]   INFO -       #com.jetbrains.cidr.lang - Saving symbols finished in 0 s. 

Answer 1

This pops up at the top when you google "cannot resolve symbol MultiDexApplication". Thus, I add what helped me:

• If you changed the targetSdkVersion from < 21 to 21+ you see this error

• Reason: You only need to MyApplication extends MultiDexApplication when targeting API < 21 see documentation.

I.e. to fix it just:

public class MyApplication extends Application

Answer 2

    MultiDex.install(this); 

removed this lines in Applicationenter code here