Book Image

Mastering Android Development with Kotlin

By : Miloš Vasić
Book Image

Mastering Android Development with Kotlin

By: Miloš Vasić

Overview of this book

Kotlin is a programming language intended to be a better Java, and it's designed to be usable and readable across large teams with different levels of knowledge. As a language, it helps developers build amazing Android applications in an easy and effective way. This book begins by giving you a strong grasp of Kotlin's features in the context of Android development and its APIs. Moving on, you'll take steps towards building stunning applications for Android. The book will show you how to set up the environment, and the difficulty level will grow steadily with the applications covered in the upcoming chapters. Later on, the book will introduce you to the Android Studio IDE, which plays an integral role in Android development. We'll use Kotlin's basic programming concepts such as functions, lambdas, properties, object-oriented code, safety aspects, type parameterization, testing, and concurrency, which will guide you through writing Kotlin code in production. We'll also show you how to integrate Kotlin into any existing Android project.
Table of Contents (24 chapters)
Title Page
Credits
About the Author
Acknowledgments
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Requesting permissions


After the Android SDK version, 23 permissions are required to be requested at runtime (not for all of them). This means that we need to request them from the code as well. We will demonstrate how to do that from our application. We will request required permissions for the GPS location obtaining as a user opens the application. The user will get a dialog to approve permission if there is not any approved. Open your BaseActivity class and extend it as follows:

    abstract class BaseActivity : AppCompatActivity() {
      companion object { 
      val REQUEST_GPS = 0 
      ... }
      ... 
      override fun onCreate(savedInstanceState: Bundle?) {   
        super.onCreate(savedInstanceState)
        ...
        requestGpsPermissions() } 
     ...
     private fun requestGpsPermissions() {   
       ActivityCompat.requestPermissions( 
         this@BaseActivity,
         arrayOf( 
           Manifest.permission.ACCESS_FINE_LOCATION,
           Manifest.permission.ACCESS_COARSE_LOCATION...