Gradle Firebase AdMob dependency conflict with app compat v7 28.0.0

Question

When I added the AdMob dependency this red line appears:

The complete error message:

All com.android.support libraries must use the exact same version specification (mixing versions can lead to runtime crashes). Found versions 28.0.0, 26.1.0. Examples include com.android.support:animated-vector-drawable:28.0.0 and com.android.support:customtabs:26.1.0 less... (Ctrl+F1) Inspection info:There are some combinations of libraries, or tools and libraries, that are incompatible, or can lead to bugs. One such incompatibility is compiling with a version of the Android support libraries that is not the latest version (or in particular, a version lower than your targetSdkVersion). Issue id: GradleCompatible

If I try to make project appears this error message:

I've already invalidate cache/restart, re-import gradle and nothing works...

Gradle module

apply plugin: 'com.android.application'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.dev.marcellocamara.pgm"
        minSdkVersion 19
        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:support-v4:28.0.0'
    implementation 'com.android.support:design:28.0.0'
    implementation 'com.android.support:cardview-v7:28.0.0'
    implementation 'com.android.support:customtabs: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-core:16.0.8'
    implementation 'com.google.firebase:firebase-auth:16.2.1'
    implementation 'com.google.firebase:firebase-database:16.1.0'
    implementation 'com.google.firebase:firebase-storage:16.1.0'
    implementation 'com.google.android.gms:play-services-auth:16.0.1'
    implementation 'com.google.firebase:firebase-messaging:17.6.0'
    implementation 'com.google.firebase:firebase-ads:17.2.0'
}

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

Gradle app

buildscript {
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.3.2'
        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()
        maven { url "https://jitpack.io" }
    }
}

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

I viewed another answers for this same problem, but none of then was using too much lib of firebase as I am. They told to add support v7 28.0.0 and I already did it.

Answer 1

By following this doc: https://developer.android.com/studio/build/multidex

I added multiDexEnabled true to the build gradle module :

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.dev.marcellocamara.pgm"
        minSdkVersion 19
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        multiDexEnabled true
    }

Following the documentation, why I'm using min SDK as 19, I added 'com.android.support:multidex:1.0.3' as dependency to build gradle module, and finally added android:name="android.support.multidex.MultiDexApplication" to the application manifest.xml

The error messages disappear and app is running...