An activity is the single screen in android. … It is like window or frame of Java. By the help of activity, you can place all your UI components or widgets in a single screen. The 7 lifecycle method of Activity describes how activity will behave at different states.
What is the life cycle of services in Android?
Android service is a component that is used to perform operations on the background such as playing music, handle network transactions, interacting content providers etc. It doesn’t has any UI (user interface). The service runs in the background indefinitely even if application is destroyed.
What is the activity in Android?
An Android activity is one screen of the Android app’s user interface. … An Android app may contain one or more activities, meaning one or more screens. The Android app starts by showing the main activity, and from there the app may make it possible to open additional activities.
Is onCreate only called once?
@OnCreate is only for initial creation, and thus should only be called once. If you have any processing you wish to complete multiple times you should put it elsewhere, perhaps in the @OnResume method.
Is it possible activity without UI in Android?
The answer is yes it’s possible. Activities don’t have to have a UI. It’s mentioned in the documentation, e.g.: An activity is a single, focused thing that the user can do.
Which lifecycle method gets called when A goes to B come back to a?
The onDestroy method is called after back press. Then activity will be popped from the Activity back stack. From docs: If an activity is paused or stopped, the system can drop the activity from memory by either asking it to finish, or simply killing its process.
What is onCreate method in Android?
onCreate is used to start an activity. super is used to call the parent class constructor. setContentView is used to set the xml.
What is the purpose of service in Android?
A Service is an application component that can perform long-running operations in the background. It does not provide a user interface. Once started, a service might continue running for some time, even after the user switches to another application.