It is easy to find a comprehensive Android tutorial online. The open source operating system based on Linux for mobiles or smartphones and tablets is the de facto market leader and it is hence most popular among aspiring developers. Android was developed by Google led Open Handset Alliance. Although many other companies were involved in the project, Google played a major role and is the default overseer since it powers billions of phones and tablet computers using the operating system. There are different types of Android tutorial you would find online. Many are aimed at helping aspirants or beginners develop a substantial understanding of application development using Android. Others are aimed at training developers with intermediate skills.
It is quite possible for an Android tutorial to become overwhelming for beginners. The scope is massive and hence the quantum of information one must process is daunting. An Android tutorial should be simple but then if one has to explore some of the advanced concepts then complexity is unavoidable. In this guide, we shall show you how you can navigate an Android tutorial. This is precisely for beginners as intermediate developers will already be familiar with the basics and they would be better poised to grasp the new information and advanced concepts. It is another matter that progressing from intermediate to advanced Android application development can be a serious challenge.
Introduction to Android
Android is an operating system based on Linux. It is an open source program so anyone and everyone can access it and explore it in a manner they deem fit. Those who have a basic understanding or even practice of Java programming will find application development using Android a natural progressive and transformational step. Android facilitates a unified and systemic approach to developing applications for smartphones and tablets. This enables developers to design and create applications that can run on multiple devices, provided they run on Android.
Android was first launched in its beta version in 2007. Google released it as Android SDK or Software Development Kit. The commercial version was first launched in September, 2008. This was called Android 1.0. Many updated versions have been released since then. Some updates have been largely cosmetic while some have been seriously incremental with leapfrogging upgrades affecting everything from performance to functionality to user interface. The source code for the mobile operating system is available for free. Most of the source code and Linux kernel are respectively available under Apace License version 2.0 and GNU or General Public License version 2.
Popularity of Android
Introduction to Android Applications
As you may observe, Android is popular for some very obvious reasons and all the features it guarantees us have become an integral part of our lives. All applications are developed in Java using Android SDK or Software Development Kit. Android applications can be made available and sold through Google Play, Opera Mobile Store, SlideME, Mobango, Amazon Appstore and F-droid. Android is used in phones across almost two hundred countries in the world. Over one million new devices powered by Android are sold and activated every day. It is a no-brainer why Android applications are a massive market and an industry by itself.
Types of Android Applications
There are many types of Android applications available today. Most popular of them are music, news, multimedia, sports, lifestyle, food & drink, travel, weather, books, business, reference, navigation, finance, utilities and social media.
Versions of Android and API Level
There have been more than twenty versions of Android already. The API level is the integer value assigned to every version to identify the revised API framework applicable in the case. The present version of the operating system is called Marshmallow. It is Android 6.0 with API Level 23. It is preceded by Android 5.1 and Android 5.0, respectively named Lollipop MR1 and Lollipop with API Levels of 22 and 21. Earlier we had Android 4.4W with 20 API Level, also known as Kitkat Watch which was for wearables. Android 4.4 or Kitkat was for mobiles and tablets. It was API Level 19.
There were five versions of Android Jelly Bean. These were from 4.1 to 4.3. The earlier versions were Android Ice Cream Sandwich, Honeycomb, Gingerbread, Froyo, Éclair, Donut, Cupcake and Base. Some of them had more than one variant and some had no names, yet were substantial updates. Whenever you explore an Android tutorial, you would need a lucid understanding of the progression or evolution of Android. This will simplify your quest and the training would be much more effective. You would also be able to navigate the Android tutorial based on your needs so you do not get perplexed at any stage.
Environment Setup of Android
The aforementioned information should have enhanced your familiarity with Android. Now you must know the basics required to get started with an Android tutorial. You must have the prepping for Android application development. First, you need Microsoft Windows XP or any of the later versions, Linux including GNU C Library 2.7 or a later edition or Mac OS X 10.5.8 or a later version that has an Intel chip. All other tools you would need to develop applications for Android are available on the web and you can download most of them for free. If you do come across a paid or premium tool, then you should look for its open source or free alternative. There may be some proprietary tools that can work with open source programs.
You would need Java JDK5 or a later version to get started with application programming for Android. You would also require Android Studio. You can easily download the most current version of Java. Get the Java Development Kit or JDK from the official Java site of Oracle. If you are familiar with Java and have some programming experience, then you must already have it on your system. Installing the program using the instructions and the kit is quite simple.
Introduction to Architecture of Android
The sequential introduction in this Android tutorial is purposed to help you navigate a comprehensive guide. This should help you to get accustomed with the stepwise approach that would be much more systematic than trying to understand as much as you can in a jiffy. The architecture of Android is divided into several sections. Right at the crux are Linux to Linux 3.6. This is the Linux kernel with around a hundred and fifteen patches. This serves as the link between the hardware of a device and various drivers including camera, display and keypad among others.
Then there are libraries. These include WebKit, which is an open source browser engine, SQLite database and libc. Android libraries comprise of all the Java based treasure-troves that are crucial for Android development. The most important Android libraries are android.app, android.content, android.database, android.opengl, android.os, android.text, android.view, android.widget and android.webkit.
The third section is Android Runtime. The most important component of this is Dalvik Virtual Machine, a type of Virtual Machine powered by Java that is specially tasked to help you design and optimize applications with Android. This component facilitates multi threading, memory management and other essential tasks that make applications independent and capable of running their standalone processes. You have to get familiar with the Application Framework of Android. This includes Activity Manager, Content Providers, Resource Manager, Notifications Manager and View System. Finally, you have Applications right at the very top. This is where applications you develop get installed.
Introduction to Application Components of Android
The quintessential building blocks of application development using Android are called Application Components. You will find these in AndroidManifest.xml which serves as the application manifest file. You have to learn how each component interacts with another and lead to the development of the entire application. There are four major components in Android applications. These are Activities that dictate the user interface, Services that manage background processing, Broadcast Receivers that manage communication of the applications with the Android operating system and Content Providers that manage database issues and data.
Activities can be any action on the single screen. The email application showing a particular activity such as displaying the inbox, then facilitating another activity such as composing an email and then another action such as reading emails are all facilitated by the Activities component. Services is any component that keeps running or functioning in the background for operations that have to continue for completion. For instance, a music application has to keep running as a user accesses messages, social media sites or browses the internet. Services allows a task to run without limiting the ability of the user to interact with other activities.
Broadcast Receivers are responsible for processing messages among applications and from or to the system. Applications may need to know some stats or information such as how much data is available, how much storage space is required for an installation or some other vital fact that would enable the tasks to be completed. Content Providers are suppliers of data. They facilitate transfer of data among applications but on request.
There are Additional Components such as Fragments that represent a part of the user interface in a specific activity, Views that deal with elements of the user interface on screen such as list forms or buttons, Layouts that are effectively hierarchies to control screen format and how views appear, Intents that regulates wiring components, Resources that work with external elements, be it strings or constants and Manifest that is basically an application configuration file.
Always Follow a Systematic Approach to Android Tutorial
No matter what the scope of an Android tutorial is, you would need a systematic approach. This guide is not exhaustive but it sheds light on the basics that would help you to get started. As and when you master the knowledge of these distinctly different but also interrelated aspects of Android development, you can explore them in greater detail, hone your understanding and then progress to the other more complicated concepts. This entire Android tutorial pertains to beginners. Intermediate developers are already aware of these.
After developing a theoretical understanding of the various components of application development, you should use an Android tutorial that enables you to create an application. Even if you are not effectively going to develop one to be published, sold or downloaded for free, you need a real firsthand experience of what it looks and feels like to create an app from the scratch. You can find such an Android tutorial online. You may even download some comprehensive course that would include such an interactive experience. This is crucial as theoretical understanding would only be helpful till you get stuck with an error. Then you must learn to troubleshoot. Fortunately, Android is an open source operating system and there is a community of millions of developers from around the world who have had the same problems as you and can immediately offer you the help you need. Be an active part of the Android community to have a satiating adventure.