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The Difference between Views and Editors in Eclipse IDE for Java Development

You may have difficulty understanding the difference between views and editors when using Eclipse for Java development. If views and editors seem the same to you, and you’re not sure whether you can tell [more…]

Java Development: Inside a View or an Editor in Eclipse

When you use the Eclipse IDE for Java development, you’ll need to understand the inside of a view or editor. The terms defined here deal with individual views, individual editors, and individual areas. [more…]

How to Create Your First Android Project

After you have Java Runtime Environment and Android Software Development Kit (SDK) installed on your development computer, you’re ready to start Eclipse and create a real, live Android app. [more…]

Android App Troubleshooting: Error Message — R Cannot be Resolved

Every Android app has an file. The Android development tools generate this file automatically, so normally you don’t have to worry about Occasionally, the file takes longer than average [more…]

Android App Troubleshooting

When you try to run your first Android app, if your effort stalls, don’t despair. Here are some troubleshooting tips to help you resolve any problems you encounter. [more…]

A Close-Up Look at an Android App

In this figure, the Package Explorer in Eclipse shows the structure of a newly created Android project. Each branch of the tree represents a file or a folder, and if you expand all branches of the tree [more…]

All About XML Files for Android Apps

Every Android app consists of some Java code, some XML documents, and some other information. (The acronym XMLstands for eXtensible Markup Language.) You might already be familiar with HTML documents — [more…]

The gen Directory File

The directory name gen stands for generated. The gen directory contains This listing shows that part of the file generated for you when you create a brand-new project. [more…]

The Android 4.2 Branch

The tree shown in this figure has an Android 4.2 branch, but it isn’t a directory on the computer’s file system. In the Package Explorer view, the Android 4.2 [more…]

The AndroidManifest.xml File

Every Android app has an AndroidManifest.xml file. The AndroidManifest.xml file provides information that a device needs in order to run the app. The AndroidManifest.xml [more…]

The Java Class

Java is an object-oriented programming language. As a Java developer, your primary goal is to describe classes and objects. A class is a kind of category, like the category of all customers, the category [more…]

Java Keywords and Identifiers

The Java language uses two kinds of words: keywords and identifiers. You can tell which words are keywords because Java has only 50 of them. Here’s the complete list: [more…]

Method Declaration and Method Call in Java Programming

Almost every computer programming language has elements akin to Java’s methods. If you’ve worked with other languages, you may recall terms like subprogram [more…]

The Main Method in a Standard Java Program

When you run the small Java program in this listing, the computer displays the word Hello in a dialog box. The figure shows a copy of the code from the listing with arrows indicating what happens when [more…]

How to Punctuate Your Java Code

In English, punctuation is vital. Punctuation is also important in a Java program. The use of curly braces, semicolons, parentheses, double quotation marks, and periods tells Java how to read the code [more…]

How to Use Comments in Java Progamming

In Java programming, there is a difference between code written just for machines and code written to be read by people. This first listing is very simple and is meant just for machines. [more…]

10 Mistakes to Avoid in Java Programming

Here are 10 quick reminders to avoid easy mistakes when you are programming Android apps with Java code. Writing your own Java programs will be much easier and smoother when you run through this checklist [more…]

Create a Collection Class in Java

A collection class in Java code is a class whose job is to store a bunch of objects at a time — a bunch of String objects, a bunch of BagOfCheese objects, a bunch of tweets, or whatever. You can create [more…]

Arrays in Java Code

The ArrayList class that is used is in many Android app programs is only the tip of the Java collections iceberg. The Java library contains many collections classes, each with its own advantages. The table [more…]

Java's Wrapper Classes

The difference between primitive types and reference types is one of Java's most controversial features, and developers often complain about the differences between primitive values and reference values [more…]

Step through a Collection in Java Code

Some Java programs used in Android apps use a for loop with indexes to step through a collection. The code does what it's supposed to do, but it's a bit awkward. When you're piling objects into a collection [more…]

Object-Oriented Programming for Android Apps

Object-oriented programming has brought about a big change in application development and programming. An object-oriented program is, at its heart, designed to be modified. Using correctly written software [more…]

Java's Modifiers

Here are a few fun facts about Java modifiers used in Java programs like designing Android Apps. The word final has many uses in Java programs. In addition to having final variables, you can have these [more…]

Keep Things Simple with Java Classes

Most computer programs operate entirely in the virtual realm. They have no bricks, nails, or girders. So you can type a fairly complicated computer program in minutes. Even with no muscle and no heavy [more…]

Java Android Programming Example Using Classes

Classes and subclasses are shown in a practical Java Android programming example here. How does an Android app use classes and subclasses? This example is ruefully simple, but it's one that an Android [more…]

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