Android

Overview Activity Activity is a crucial component of an Android application. Unlike other programming languages, Android system starts an application from the onCreate() callback of an Activity. The user journey of a user in an application is unpredictable. For instance, a user can open an application from Home Screen or he/she can open the application from other application's Activity. Activity can be used by an application to start other application, when doing so, the source application isn't calling the entire application as a whole instead, it is calling a specific Activity which serves as contact point of that application. When you are using an Activity you must declare that Activity in the manifest file of the application. The Activity must be declared in the <activity>  tag under <application> tag < application < activity android :name =".MainActivity" android :exported ="true" > < intent-filter ...