在现有的Android Studio项目中无法连接到Firebase

Question

                   Caused by: java.lang.IllegalStateException: Default FirebaseApp is not initialized in this process com.dji.GSDemo.GoogleMap. Make sure to call FirebaseApp.initializeApp(Context) first.

Could not parse the Android Application Module's Gradle config. Resolve gradle build issues and/or resync.

apply plugin: 'com.android.application'

android {
    compileSdkVersion 27
defaultConfig {

    ndk {
        abiFilters 'armeabi-v7a'
    }

    applicationId "com.dji.GSDemo.GoogleMap"
    minSdkVersion 23
    targetSdkVersion 26
    versionCode 1
    versionName "1.0"
    //Enabling multidex support
    multiDexEnabled true //Mention in the doc

}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}

//Mention in the doc
dexOptions {
    incremental = true;
    preDexLibraries = false
    javaMaxHeapSize "4g" // 2g should be also OK
}

packagingOptions{
    doNotStrip "*/*/libdjivideo.so"
    doNotStrip "*/*/libSDKRelativeJNI.so"
    doNotStrip "*/*/libFlyForbid.so"
    doNotStrip "*/*/libduml_vision_bokeh.so"
    doNotStrip "*/*/libyuv2.so"
    doNotStrip "*/*/libGroudStation.so"
    doNotStrip "*/*/libFRCorkscrew.so"
    doNotStrip "*/*/libUpgradeVerify.so"
    doNotStrip "*/*/libFR.so"
}
}
dependencies {

compile fileTree(include: ['*.jar'], dir: 'libs')
testCompile 'junit:junit:4.12'

implementation 'com.android.support:appcompat-v7:27.0.2'
compile 'com.android.support:design:27.0.2'
compile 'com.google.android.gms:play-services-gcm:11.8.0'
implementation 'com.google.android.gms:play-services:11.8.0'
implementation 'com.android.support:support-v4:27.0.2'
implementation 'com.google.firebase:firebase-database:11.8.0'
implementation 'com.google.android.gms:play-services-maps:11.8.0'
implementation 'com.google.firebase:firebase-messaging:11.8.0'
implementation 'com.android.support.constraint:constraint-layout:1.0.2'
implementation 'com.google.firebase:firebase-auth:11.8.0'
implementation 'com.firebaseui:firebase-ui-database:2.3.0'
implementation 'com.google.android.gms:play-services-location:11.8.0'
implementation 'com.github.medyo:android-about-page:1.2.1'
implementation 'com.google.android.gms:play-services-places:11.8.0'
compile 'com.github.medyo:android-about-page:1.2.1'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.1'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
implementation 'com.android.support:cardview-v7:27.0.2'

implementation 'com.android.support:appcompat-v7:27.0.2'
implementation 'com.android.support:animated-vector-drawable:27.0.2'
implementation 'com.android.support:mediarouter-v7:27.0.2'


compile 'com.android.support:multidex:1.0.1'
compile 'com.google.android.gms:play-services-ads:11.8.0'

compile ('com.dji:dji-sdk:4.4.1')
provided ('com.dji:dji-sdk-provided:4.4.1')
}

Answer 1

implementation 'com.firebaseui:firebase-ui-database:2.3.0'

implementation 'com.firebaseui:firebase-ui-database:3.2.2'