Apps for Android- Today we will start with a new series of posts dedicated to the development of Android apps. It will be a basic Android development course divided into four parts. Today we will begin with the first part, the theoretical part, where we will explore concepts, history. And forms of development in the reference mobile operating system. Welcome to our Introduction to the Development of Apps for Android course.
DEVELOPMENT OF APPS FOR ANDROID
Android is an operating system that covers a large number of different mobile devices. And is the technology mostly used in mobile devices. The sale of Android applications is in continuous growth in such a way that it is becoming an indispensable requirement for companies. Programming for Android is entertainment. As is the professional future for programmers.
Android is a free software with license Apache license so that any developer can modify and improve their code. Android is usually done with the Java- like programming language and the SDK (Software Development Kit) development toolkit. But there are also other options available.
As mentioned earlier Android has an SDK which provides a number of tools for development. As well as allowing us to generate an emulator by choosing the size of the device’s screens as well as selecting the version of Android that you want to use.
The SDK allows us to access the hardware of the device such as wifi, bluetooth, access to photos. And videos of phone, microphone, camera. As well as it is also possible to make and receive calls and send SMS among other options.
FUNDAMENTALS OF AN APPLICATION
The first thing we have to mention is that the applications are developed in the object-oriented Java programming language. At the moment of developing an application with the help of the SDK, an APK file (Android package) is generated where the written code will be inserted. With all its resources, libraries and tools used. This file will be the installer of our app.
After installing the application each of them have a security system so that each application will be a different user within Android. You will be granted permissions to the files of an application only for the user who identifies it.
Each process has its own virtual machine, this means that the execution of the applications are totally independent of each other. Each of them runs in its own Linux process which is managed at the Operating System level.
Since we now know how Android works, it is necessary to understand the components of an application.
COMPONENTS OF AN ANDROID APPLICATION
One of these components is called Activity , which is a separate screen with a user interface. In our application we will have several activities. Which are going to be interconnected with each other. Allowing the user to navigate the app sending data if it is considered necessary.
At the time of generating a screen the Android Studio development platform allows us to do it graphically. By dragging and dropping elements (buttons, text boxes, etc.). Or by means of code giving the programmer the option to do it in the way that the be more comfortable
The next component is the Service , which runs deep in the application to perform long-term operations or work in remote processes. Which unlike the Activity, does not have a user interface.
The Content Provider in the component that allows us to manage a data set of the application to share. A very common example is to share contacts between applications. As well as the location of the device or our own data set.
The fourth component is Broadcast Receiver. Which is responsible for allowing us to respond to broadcast announcements of the system. Such as when the device is running out of battery, as well as many other announcements.
It is interesting to know that Android allows us to open a component of an application external to ours. This means that if we need the camera of the device we can create an Activity that contains it or open the component of the camera that is already installed by default in The operating system.
To know what components our application has available, there is a file called Android. This file will be responsible for communicating to the operating system what components the application has. The permissions that the app needs to operate. Such as GPS, camera, microphone, etc. It will also indicate the external libraries that the application uses. Such as Google Maps, and the minimum version of Android required.
There are several reasons to choose the development for Android because it is a free software and can be modified to suit the programmer. It allows us to create applications with total freedom almost without having to worry about the hardware of the device.
At the time of development it is not necessary that you have a mobile device with the Android operating system installed. Since the SDK allows you to create a virtual machine simulating any device. We must emphasize the importance of the SDK. Since it provides us with many essential aids at the time of development.