未解决的依存关系：无法解决：核心

Question

从下面的代码中，我收到此错误Failed to resolve: core。

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.3'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        jcenter()
        google()
    }
}

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

build gradle: module(app)

apply plugin: 'com.android.application'

android {
    signingConfigs {
        config {
            keyAlias 'btblog'
            keyPassword '718611'
            storeFile file('C:/Users/user/Downloads/btblogkey.jks')
            storePassword '718611'
        }
    }
    compileSdkVersion 26
    buildToolsVersion '27.0.3'
    defaultConfig {
        applicationId "com.best.technoblog"
        minSdkVersion 22
        targetSdkVersion 26
        versionCode 4
        versionName "2.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

repositories {
    maven {url "https://jitpack.io"}
}

    dependencies {
        implementation fileTree(dir: 'libs', include: ['*.jar'])
        testImplementation 'junit:junit:4.12'
        implementation 'com.android.support:appcompat-v7:26.1.0'
        implementation 'com.android.support:design:26.1.0'
        implementation 'com.android.support:cardview-v7:26.1.0'
        implementation 'com.android.support:recyclerview-v7:26.1.0'
        implementation 'com.android.support:support-v4:26.1.0'
        implementation 'com.android.support:preference-v7:26.1.0'
        implementation 'com.android.support:preference-v14:26.1.0'
        implementation 'com.mcxiaoke.volley:library:1.0.19'
        implementation 'com.github.mrengineer13:snackbar:1.2.0'
        implementation 'com.marshalchen.ultimaterecyclerview:library:0.3.17'
        implementation 'com.lsjwzh:materialloadingprogressbar:0.5.5-RELEASE'
        implementation 'com.google.firebase:firebase-core:16.0.1'
        implementation 'com.google.firebase:firebase-ads:15.0.1'
        implementation 'com.google.firebase:firebase-auth:16.0.2'
        implementation 'com.google.firebase:firebase-messaging:17.1.0'
        implementation 'com.google.android.gms:play-services-auth:15.0.1'
        implementation 'com.google.android.gms:play-services-maps:15.0.1'
        implementation 'com.google.android.gms:play-services-location:15.0.1'
        implementation 'com.github.AndroidDeveloperLB:MaterialPreferenceLibrary:5'
        implementation 'com.github.ksoichiro:android-observablescrollview:1.6.0'
        implementation 'net.i2p.android.ext:floatingactionbutton:1.10.0'
        implementation 'com.mikepenz:iconics-core:1.7.9@aar'
        implementation 'com.mikepenz:google-material-typeface:1.2.0.1@aar'
        implementation 'com.mikepenz:community-material-typeface:1.2.64.1@aar'
        implementation 'com.rengwuxian.materialedittext:library:2.1.4'
        implementation 'com.makeramen:roundedimageview:2.2.1'
        implementation('com.mikepenz:materialdrawer:4.4.4@aar') {
            transitive = true
        }
        implementation('com.github.afollestad.material-dialogs:core:0.8.5.0@aar') {
            transitive = true
        }
    }