Java Programming for Android Developers For Dummies, 2nd Edition

Chapter 4

An Ode to Code

IN THIS CHAPTER

Understanding how an Android activity works

Creating classes and methods

Adding comments to your code

Watching the flow in an Android activity

Hello, hello, hello, … hello!

—THE THREE STOOGES IN DIZZY DETECTIVES AND OTHER SHORT FILMS

In Chapter 3, you create a Hello World app for Android. You do this with the help of Android Studio and, in the process, Android Studio composes some Java code for you. In Chapter 3, you examine a bit of this Java code.

But in Chapter 3, you only scratch the code's surface. In this chapter, you begin to examine the code in depth. When you understand how the code works, you can forge ahead to create bigger and better Android apps.

Hello, Android!

When you create a new Android app and you select Empty Activity in the Add an Activity dialog box, Android Studio creates the Java code shown in Listing 4-1.

LISTING 4-1: A Small Android Java Program

package com.allyourcode.a04_01;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;public class MainActivity extends AppCompatActivity { @Override ...