Book Image

Android Studio 4.0 Development Essentials - Java Edition

By : Neil Smyth
Book Image

Android Studio 4.0 Development Essentials - Java Edition

By: Neil Smyth

Overview of this book

Android rolls out frequent updates to meet the demands of the dynamic mobile market and to enable its developer community to lead advancements in application development. This book focuses on the updated features of Android Studio (the fully integrated development environment launched by Google) to build reliable Android applications using Java. The book starts by outlining the steps necessary to set up an Android development and testing environment. You’ll then learn how to create user interfaces with the help of Android Studio Layout Editor, XML files, and by writing the code in Java. The book introduces you to Android architecture components and advanced topics such as intents, touchscreen handling, gesture recognition, multi-window support integration, and biometric authentication, and lets you explore key features of Android Studio 4.0, including the layout editor, direct reply notifications, and dynamic delivery. You’ll also cover Android Jetpack in detail and create a sample app project using the ViewModel component. Finally, you’ll upload your app to the Google Play Console and handle the build process with Gradle. By the end of this book, you’ll have gained the skills necessary to develop applications using Android Studio 4.0 and Java.
Table of Contents (88 chapters)
88
Index

24.7 Converting Density Independent Pixels (dp) to Pixels (px)

The next task in this exercise is to set the width of the EditText view to 200dp. As outlined in the chapter entitled “An Android Studio Layout Editor ConstraintLayout Tutorial” when setting sizes and positions in user interface layouts it is better to use density independent pixels (dp) rather than pixels (px). In order to set a position using dp it is necessary to convert a dp value to a px value at runtime, taking into consideration the density of the device display. In order, therefore, to set the width of the EditText view to 200dp, the following code needs to be added to the class:

package com.ebookfrenzy.javalayout;

.

.

import android.content.res.Resources;

import android.util.TypedValue;

 

public class MainActivity extends AppCompatActivity {

 

    private int convertToPx(int value) {

        Resources...