SetContentView is used to fill the window with the UI provided from layout file incase of setContentView(R. layout. somae_file). Here layoutfile is inflated to view and added to the Activity context(Window).
Why would you do the setContentView () in onCreate () of activity class?
As onCreate() of an Activity is called only once, this is the point where most initialization should go: calling setContentView(int) to inflate the activity’s UI, using findViewById to programmatically interact with widgets in the UI, calling managedQuery(android.
What is the purpose of super On create in Android?
The super keyword refers to superclass (parent) objects. It is used to call superclass methods, and to access the superclass constructor. The most common use of the super keyword is to eliminate the confusion between superclasses and subclasses that have methods with the same name.
What is the role of activity in Android?
In this way, the activity serves as the entry point for an app’s interaction with the user. You implement an activity as a subclass of the Activity class. An activity provides the window in which the app draws its UI. … Generally, one activity implements one screen in an app.
Why we use onCreate method in Android?
onCreate(Bundle savedInstanceState) Function in Android:
Basically Bundle class is used to stored the data of activity whenever above condition occur in app. onCreate() is not required for apps. But the reason it is used in app is because that method is the best place to put initialization code.
What is the difference between onCreate and onStart Android?
onCreate() is called when the when the activity is first created. onStart() is called when the activity is becoming visible to the user.
What does finish () do in Android?
finish() work in android. On Clicking the back button from the New Activity, the finish() method is called and the activity destroys and returns to the home screen.
When onPause method is called in Android?
onPause. Called when the Activity is still partially visible, but the user is probably navigating away from your Activity entirely (in which case onStop will be called next). For example, when the user taps the Home button, the system calls onPause and onStop in quick succession on your Activity .
How do I know if my android activity is destroyed?
setText(values[0]); } else //Activity is destroyed { //Take appropriate action!! } The advantage will be, if the activity is destroyed by the time you reach this statement, your Context will automatically become null and you can handle the scenario.
What is super () in Java?
The super() in Java is a reference variable that is used to refer parent class constructors. … If a constructor does not explicitly invoke a superclass constructor by using super(), the Java compiler automatically inserts a call to the no-argument constructor of the superclass.
What is Android activity life cycle?
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 are the main components in Android?
Introduction. There are four main Android app components: activities , services , content providers , and broadcast receivers . Whenever you create or use any of them, you must include elements in the project manifest.
What are the types of intent in android?
Android supports two types of intents: explicit and implicit. When an application defines its target component in an intent, that it is an explicit intent.
What is onCreate () method?
onCreate is used to start an activity. super is used to call the parent class constructor. setContentView is used to set the xml.
How do I use getIntent on Android?
you can retrieve this data using getIntent in the new activity: Intent intent = getIntent(); intent. getExtra(“someKey”) … So, it’s not for handling returning data from an Activity, like onActivityResult, but it’s for passing data to a new Activity.
What is onStart method in Android?
onStart(): This method is called when an activity becomes visible to the user and is called after onCreate. onResume(): It is called just before the user starts interacting with the application. … onDestroy(): It is called when the activity is cleared from the application stack.