The best features that come with apps are what pique consumers' curiosity. Apps make phones "today smart," and their benefits have dramatically altered how we work today. Expert programmers are hard at work, creating and constructing their own programs and infusing them with beneficial features. In this post, we will go over the following topics for Beginners Android App Development that you should be aware of before beginning to build an Android application:
- 1. Introduction to Android
- 2. Master the language
- 3. Right application development tools and environment
- 4. Application components
- 5. The android application, threads, loaders, and tasks
- 6. Choosing the right tools
- 7. Conclusion
1. Introduction to Android:
What is Android?
Android is an operating system built for mobile devices, where mobile devices are defined by the presence of touch displays and sensors. The fact that the Android operating system is based on the Linux kernel is an essential feature. And, in order to execute a program, it is powered by a Java-based virtual machine known as the Dalvik VM.
Basic Architecture of Android
APPs (top layer): Android apps are Java-based programs that are compiled into byte code, packaged, and deployed on the Android system.
Application Framework (layer 2): The application framework is the layer that offers the services required for Android apps to execute, such as the window manager, telephony manager, location manager, and resource managers, among others.
Android Native Libraries (layers 3–1): Android native libraries provide APIs for a variety of functions. For example, database APIs (such as SQLite), WebKit APIs, SSL APIs, OpenGL, and so on.
Android Runtime (layer 3–2): In addition to the libraries, the same layer contains the Android runtime, which comprises of the Dalvik virtual machine, as previously explained, as well as the core Java libraries. The core Java libraries are essentially the Android equivalent of the standard Java libraries, often known as JDKs.
Linux Kernel (basic layer): As previously stated, this is the foundation of the Android operating system and is a regular Linux kernel with certain tweaks developed by Google that may be used to communicate with devices.
2. Master the Language
The two most common programming languages used in Android app development are Java and XML. As a result, knowledge and expertise in these programming languages are required before developing an Android app. The following are some of the principles of the Java programming language:
- 1. Packages
- 2. Objects & classes
- 3. Inheritance & interfaces
- 4. Strings & numbers, generics
- 5. Collections
- 6. Concurrency
Proper understanding of Java and XML will help you build/develop a more robust and elegant android app.
3. Right application development tools and environment
If you are new to Android app development, it is critical that you become acquainted with the build automation tools as well as the integrated development environment before beginning to develop your app. For the tools, you may use Android app studio IDE or Eclipse; these will help you understand the basics and many other things that will help you better your code. You may study Apache Maven, Apache Ant, and Gradle since they offer a robust collection of tools for controlling your builds.
It is also critical that you become acquainted with source control tools and principles. Learn how to use git and then set up a git-source repository (by creating an account on Bitbucket or GitHub). The Git Pocket Guide can help you learn the fundamental principles and words that govern how the platform works.
The Definition of Activities
A single screen with a user interface constitutes an activity (UI). A phone dialer, for example, is an activity. Here are some additional facts regarding activities to consider.
- 1. Independent Units: Activities are self-contained units.
- 2. Coherence refers to the ability of activities to work together to generate coherent wholes.
- 3. Activities that may be triggered by other apps are known as invocable activities (i.e. invoke the camera)
- 4. Extendable: We can develop an activity by simply extending the Android system's activity class.
The Definition of Service
A service is an application component that runs in the background, generally for a long time, without interacting with the user. It is a method for the app to notify the system of anything that it want to continue doing in the background even after the user exits the app. As an example,
- 1. A service for playing music
- 2. A download service
Services, unlike activities, do not provide a UI since they run in the background and do not interact with the user. Similarly to activities, creating a service is as simple as extending the service class. Here are some of the most common applications for the services:
- 1. A way for APPs to run in the background
- 2. A way for applications to expose some of this functionality. By doing so, applications can bind to the service and use the service.
4. Application components
The basic pieces of Android app development are known as application components. Each component represents a distinct entry point for the system into your program. Although each one exists as a distinct entity and serves a specific purpose, there are some that rely on one another, and not all of them serve as true entry points.
There are five basic sorts of app components, each with its own function and life cycle that governs how it is generated and destroyed. They are as follows:
This component depicts a single screen with a user interface (for instance, an email app may have one activity showing a list of new emails, another activity composing emails, and another one reading emails). Activities in the app work together to create a unified user experience. Each of them, though, is self-contained.
This is a background component that does work for remote processes or long-running procedures. It lacks a graphical user interface (for instance it might play music in the background while the user is in a different app).
• Content providers:
This is the component in charge of managing a common collection of app data. This component allows you to query or even modify data stored in the file system, the web, or a SQLite database (as long as the content provider allows it). This component may also be used to write and read data that is not shared and is only accessible to your app.
• Broadcast receivers:
This is the component responsible for responding to system-wide broadcast announcements. The majority of broadcast receivers are generated by the system, and while they do not have a user interface, they can generate a status bar message that notifies the user when a broadcast event happens. In general, it serves as a gateway to the other components and performs only minor functions.
• Activating components:
A synchronous communication known as intent activates three of the four components (i.e. services, activities, and broadcast receivers). Intents also connect specific components to one another at runtime, regardless of whether the component is part of your programme.
Types of Bindings
When we utilise intentions, it really executes an action in one activity and initiates another activity as a result. There are several methods for this to occur.
- Direct Binding for Activities: The activity or app that generated the intent will initiate an activity from another application.
- Direct Binding for Services:The service might be started directly by the app that generated the intent.
- Broadcast:The behavior that is causing the intent, and it might broadcast the event to any broadcaster receivers who are interested
5. The Android Application, Threads, Loaders, and Tasks
Android is a dispersed market with several devices and operating system versions. It should be noted that if your gadget supports additional devices and/or versions, it will undoubtedly necessitate more maintenance and testing, as well as the associated expenditures. The opposite is also true. You will also need proper fonts, assets, and layouts to ensure that the greatest possible experiences in the various screen characteristics are provided. You should also think about the array of Android-supported sensors and UI features. An application class, one or more activities, and one or more fragments are all part of any Android app.
You may have services for background activities that should run constantly at times, but not always. If you want to provide a beautiful and seamless user interface, make sure the thread is never blocked. As a result, large operations (computations, I/O, network, and so on) should all be performed asynchronously in the background (mainly on a different thread of execution). This is why it is critical to understand the Java language's concurrency features.
6. Choosing the right tools
You only need a Mac or Windows PC, any form of Linux, plus Eclipse, the ADT Plugin, and the Android SDK, all of which are free. You may learn how to set up your development environment by reading the installation guide on Google; it includes documentation for everything you need. When developing an Android app, you need keep several specific requirements in mind. Among them are the following:
- 1. Performance and responsiveness: Always reply to user input within five seconds or the operating system will ANR you. (ANR-application not responding – your only choice is to force close your app.)
- 2. Users will detect lags of greater than 100 milliseconds: As previously stated, because there is only one UI thread, it should never be blocked.
- 3. Scarcity of resources: Wake-locks (the mechanism that forces the device to accomplish something against the battery manager's advise to put the device to sleep) should be used sparingly. Unnecessary polling of hardware (e.g., GPS or accelerometer) may quickly deplete the battery.
Check out our video that takes you through the introduction to Android Application Development to get a taste of what the course entails.
Consider the instance of a phone call that occurs while you're drafting an email message. In such instances, the phone programme takes the place of your email client and moves to the foreground.
Whether you opt to start with a small app on your own or employ a top Android App development company to construct a more sophisticated solution, there is still a lot to learn.