Creating a android application is not an easy process, but also not a difficult one. If you have some interest in programming, you can create a fully working android application. Before going to the actual topic, it is good to known the basic of the android app, which is the life cycle of an android app.
Check this link to known more about activity lifecycle in android.
https://developer.android.com/guide/components/activities/activity-lifecycle
You should have the full understanding of the activity life cycle before creating a application. Android application can be written in various programming languages such as java , python, dart etc. To create a android application using java , we use android studio.
Download the latest version of android studio here,
https://developer.android.com/studio
After downloading the latest version of android studio, we will create a new project. We can use either java or kotlin as a programming language in android studio.
After creating a project, there will be two files which have the extensions xml and java. Designing is carried out in xml, and the coding is written in java file .After writing all the codes and designing, we can run the code, to show the preview of the application.
We can also , build an apk file in android studio, and most importantly we can sign it, and launch it in any app store.