Android app components

Android apps typically consist of some, or all, the four different components listed following:

  • Activities
  • Services
  • Broadcast receivers
  • Content providers

Activities

An activity provides a screen with which users can interact in order to do something. Sometimes, it could include a few fragments inside. A fragment represents a behaviour or a portion of user interface in an activity. Users can perform operations such as making a call, sending an SMS, and so on. A good example of an activity could be the login screen of your Facebook app. The following screenshot shows the activity of the calculator application:

Activities

Services

A service can ...

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