Book Image

Android Studio 3.5 Development Essentials - Java Edition

By : Neil Smyth
Book Image

Android Studio 3.5 Development Essentials - Java Edition

By: Neil Smyth

Overview of this book

Android applications have become an important part of our daily lives and lots of effort goes into developing an Android application. This book will help you to build you own Android applications using Java. Android Studio 3.5 Development Essentials – Java Edition first teaches you to install Android development and test environment on different operating systems. Next, you will create an Android app and a virtual device in Android Studio, and install an Android application on emulator. You will test apps on physical Android devices, then study Android Studio code editor and constraint layout, Android architecture, the anatomy of an Android app, and Android activity state changes. The book then covers advanced topics such as views and widgets implementation, multi-window support integration, and biometric authentication, and finally, you will learn to upload your app to Google Play console and handle the build process with Gradle. By the end of this book, you will have gained enough knowledge to develop powerful Android applications using Java.
Table of Contents (86 chapters)
86
Index

32.7 Modifying the Fragment

The fragment class now needs to be updated to react to button clicks and to interact with the data values stored in the ViewModel. The class will also need references to the three views in the user interface layout to react to button clicks, extract the current dollar value and to display the converted currency amount. With the MainFragment class file loaded into the code editor, modify the onActivityCreated() method to obtain and store references to the three view objects as follows:

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import android.widget.Button;

import android.widget.EditText;

import android.widget.TextView;

 

import com.ebookfrenzy.viewmodeldemo.R;

 

public class MainFragment extends Fragment {

 

    private MainViewModel mViewModel;

    private EditText dollarText;

    private TextView resultText;

    private Button convertButton;

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