Book Image

Android Studio 4.2 Development Essentials - Kotlin Edition

By : Neil Smyth
Book Image

Android Studio 4.2 Development Essentials - Kotlin Edition

By: Neil Smyth

Overview of this book

Android Studio is an Integrated Development Environment that is based on the JetBrains IntelliJ IDEA. It provides developers with a unique platform to design and develop Android apps using various developer tools. The new Android Studio 4.2 has an upgraded IntelliJ platform and a variety of new features designed to improve the productivity of Android app developers. Fully updated for Android Studio 4.2, the objective of this book is to help you master the skills necessary to develop Android applications using Kotlin as the programming language. This book begins by outlining the steps necessary to set up an Android development and testing environment and introduces programming in Kotlin, addressing data types, flow control, functions, lambdas, and object-oriented programming. It includes an overview of Android Studio, covering areas such as tool windows, the code editor, and the Layout Editor tool. An introduction to Android architecture is followed by an in-depth explanation of the design of Android applications and user interfaces using the Android Studio environment. Early chapters detail Android Architecture components like view models, lifecycle management, Room database access, the Database Inspector, app navigation, live data, and data binding. Advanced topics such as intents are also covered, as are touch screen handling, gesture recognition, and the recording and playback of audio. You will also explore printing, transitions, cloud-based file storage, and foldable device support. Detailed descriptions of material design concepts are provided, including the use of floating action buttons, Snackbars, tabbed interfaces, card views, navigation drawers, and collapsing toolbars. Some key features of Android Studio 4.2 and Android discussed in-depth include the Layout Editor, the ConstraintLayout and ConstraintSet classes, MotionLayout Editor, view binding, constraint chains, barriers, and direct reply notifications. Later chapters cover advanced features of Android Studio such as App links, Dynamic Delivery, the Android Studio Profiler, Gradle build configuration, and submitting apps to the Google Play Developer Console.
Table of Contents (94 chapters)
94
Index

16.9 Calling Methods and Accessing Properties

Now is probably a good time to recap what we have done so far in this chapter. We have now created a new Kotlin class named BankAccount. Within this new class we declared primary and secondary constructors to accept and initialize account number, balance and customer name properties. In the preceding sections we also covered the steps necessary to create and initialize an instance of our new class. The next step is to learn how to call the instance methods and access the properties we built into our class. This is most easily achieved using dot notation.

Dot notation involves accessing a property, or calling a method by specifying a class instance followed by a dot followed in turn by the name of the property or method:

classInstance.propertyname

classInstance.methodname()

For example, to get the current value of our accountBalance instance variable:

val balance1 = account1.accountBalance

Dot notation can also be used...