Android - Context

android/content/Context: Interface to global information about an application environment.

An activity is a subclass of context and is therefore a context.

• displaying different kind of data
• of switching from viewing to entering data

In a layout file, see the tools:context attribute.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    tools:context=".MainActivity">

....

</RelativeLayout>