INTRODUCTION TO ANDROID APPLICATIONS
An Android app is a software application running on the Android platform. Because the Android platform is built for mobile devices, a typical Android app is designed for a smartphone or a tablet PC running on the Android OS.
Although an Android app can be made available by developers through their websites, most Android apps are uploaded and published on the Android Market, an online store dedicated to these applications. The Android Market features both free and priced apps. Android apps are written in the Java programming language and use Java core libraries. They are first compiled to Dalvik executables to run on the Dalvik virtual machine, which is a virtual machine specially designed for mobile devices.
The Android platform has been around for more than ten years, and since its early days it has had great support for the Web. It shipped with WebView, a component that allows developers to use the web inside their own Android Apps. Developers can include the web in their Android applications in many ways. WebView is frequently used to render ads, as a layout component used along with Android UI elements, or for packaging HTML 5 games. Custom Tabs allows developers to build in-app browsers and provide a seamless navigation experience to third-party web content, and Trusted Web Activity allows developers to use their Progressive Web Apps (PWAs) in Android apps, which can be downloaded from the Play Store.