Book Image

Android Programming for Beginners

By : John Horton, Paresh Mayani
Book Image

Android Programming for Beginners

By: John Horton, Paresh Mayani

Overview of this book

Android is the most popular OS in the world. There are millions of devices accessing tens of thousands of applications. It is many people's entry point into the world of technology; it is an operating system for everyone. Despite this, the entry-fee to actually make Android applications is usually a computer science degree, or five years’ worth of Java experience. Android Programming for Beginners will be your companion to create Android applications from scratch—whether you’re looking to start your programming career, make an application for work, be reintroduced to mobile development, or are just looking to program for fun. We will introduce you to all the fundamental concepts of programming in an Android context, from the Java basics to working with the Android API. All examples are created from within Android Studio, the official Android development environment that helps supercharge your application development process. After this crash-course, we’ll dive deeper into Android programming and you’ll learn how to create applications with a professional-standard UI through fragments, make location-aware apps with Google Maps integration, and store your user’s data with SQLite. In addition, you’ll see how to make your apps multilingual, capture images from a device’s camera, and work with graphics, sound, and animations too. By the end of this book, you’ll be ready to start building your own custom applications in Android and Java.
Table of Contents (37 chapters)
Android Programming for Beginners
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Deleting a note – introducing OnLongClick


As a final improvement to Note To Self and as an excuse to talk about a neat Android UI feature, we will add the ability to delete a note. Context actions are often chosen in Android apps by long clicking. Long clicking is when the user holds their finger on the device screen rather than simply tapping and removing their finger.

First, let's add a delete note method to the NoteAdapter class. Here is the code that removes a Note object from the array list and then asks the adapter to update itself and ListView:

public void deleteNote(int n){

  noteList.remove(n);
  notifyDataSetChanged();

}

Now, in onCreate, we can prepare ListView to accept long clicks and then use an anonymous class to listen and respond to them. This inner class simply calls our new deleteNote method. Add this code just before the anonymous class that handles the regular click of ListView and just after the call to setAdapter. Here, I have included the context and highlighted the...