Convert to Kotlin

app/build.gradle

@@ -29,11 +29,12 @@ android {
 dependencies {
     implementation 'com.google.android.material:material:1.4.0'
     implementation 'androidx.localbroadcastmanager:localbroadcastmanager:1.0.0'
+    implementation 'androidx.preference:preference-ktx:1.1.1'
     googleImplementation 'com.google.firebase:firebase-core:19.0.0'
     googleImplementation 'com.google.firebase:firebase-analytics:19.0.0'
     googleImplementation 'com.google.firebase:firebase-messaging:22.0.0'
     googleImplementation 'com.google.firebase:firebase-crashlytics:18.1.0'
-    implementation "androidx.core:core-ktx:1.6.0"
+    implementation 'androidx.core:core-ktx:1.6.0'
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
 }