Add dependency libraries

app/build.gradle

@@ -1,5 +1,6 @@
 apply plugin: 'com.android.application'
 apply plugin: 'kotlin-android'
+apply plugin: 'kotlin-kapt'
 apply plugin: 'kotlin-android-extensions'
 
 android {
@@ -30,20 +31,36 @@ android {
 
 dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
-    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
-    implementation 'androidx.appcompat:appcompat:1.1.0'
-    implementation 'androidx.core:core-ktx:1.1.0'
-    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
-    implementation 'com.google.android.material:material:1.0.0'
-    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
-    implementation 'androidx.navigation:navigation-fragment:2.1.0'
-    implementation 'androidx.navigation:navigation-ui:2.1.0'
-    implementation 'androidx.lifecycle:lifecycle-extensions:2.1.0'
-    implementation 'androidx.navigation:navigation-fragment-ktx:2.1.0'
-    implementation 'androidx.navigation:navigation-ui-ktx:2.1.0'
-    testImplementation 'junit:junit:4.12'
-    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
-    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
+    implementation "com.google.android.material:material:$supportLib"
+    implementation "androidx.appcompat:appcompat:$supportLib"
+    implementation "androidx.legacy:legacy-support-v4:$supportLib"
+    implementation "androidx.constraintlayout:constraintlayout:$constraintLayout"
 
-    implementation 'androidx.preference:preference:1.1.0'
+    implementation "androidx.core:core-ktx:$ktx"
+    implementation "androidx.preference:preference:$preference"
+
+    // architecture components
+    implementation "androidx.navigation:navigation-fragment-ktx:$navigation"
+    implementation "androidx.navigation:navigation-runtime-ktx:$navigation"
+    implementation "androidx.navigation:navigation-ui-ktx:$navigation"
+    implementation "androidx.lifecycle:lifecycle-extensions:$lifecycle"
+    implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:$lifecycle"
+    implementation "androidx.work:work-runtime-ktx:$work"
+    implementation "androidx.paging:paging-runtime:$paging"
+    implementation "androidx.room:room-runtime:$room"
+    implementation "androidx.room:room-ktx:$room"
+    kapt "androidx.room:room-compiler:$room"
+
+    // retrofit
+    implementation "com.squareup.retrofit2:retrofit:$retrofit"
+    implementation"com.squareup.retrofit2:converter-gson:$retrofit"
+
+    // predict4java
+    implementation "com.github.davidmoten:predict4java:$predict4java"
+
+    // testing
+    testImplementation "junit:junit:$junit"
+    androidTestImplementation "androidx.test:runner:$runner"
+    androidTestImplementation "androidx.test.espresso:espresso-core:$espresso"
 }

build.gradle

@@ -10,8 +10,6 @@ buildscript {
     dependencies {
         classpath 'com.android.tools.build:gradle:3.5.1'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
-        // NOTE: Do not place your application dependencies here; they belong
-        // in the individual module build.gradle files
     }
 }
 
@@ -19,10 +17,31 @@ allprojects {
     repositories {
         google()
         jcenter()
-        
     }
 }
 
 task clean(type: Delete) {
     delete rootProject.buildDir
 }
+
+ext {
+    supportLib = '1.0.0'
+    constraintLayout = '1.1.3'
+
+    ktx = '1.1.0'
+    preference = '1.1.0'
+
+    navigation = '2.1.0'
+    lifecycle = '2.1.0'
+    work = '2.2.0'
+    paging = '2.1.0'
+    room = '2.2.0'
+
+    retrofit = '2.6.2'
+
+    predict4java = '1.3.1'
+
+    junit = "4.12"
+    runner = '1.1.1'
+    espresso = '3.2.0'
+}