- How many types of services are there in Android?
- What are Android activities?
- Why do we set content view in onCreate?
- What does setOnClickListener do in Android?
- How do I use onStart on Android?
- What is the purpose of setContentView () function?
- What is the use of savedInstanceState in Android?
- What is onResume method in Android?
- How do I use onPause in Android?
- How do I change content view on Android?
- What is R layout?
- What are the two types of intent in android?
- What is the use of intent in android?
- What does Super onCreate do?
- What is the use of onCreate method in Android?
- What does finish () do in Android?
- Can I create activity without XML file?
- What is the use of the setContentView function in an app code?
How many types of services are there in Android?
four different typesThere are four different types of Android services: Bound Service – A bound service is a service that has some other component (typically an Activity) bound to it.
A bound service provides an interface that allows the bound component and the service to interact with each other..
What are Android activities?
An activity represents a single screen with a user interface just like window or frame of Java. Android activity is the subclass of ContextThemeWrapper class.
Why do we set content view in onCreate?
It’s the sort of task that you want to run at most once. During the lifetime of your Activity class onCreate gets called exactly once. onResume and onStart will get called multiple times without your Activity getting destroyed.
What does setOnClickListener do in Android?
OnClickListener and wires the listener to the button using setOnClickListener(View. OnClickListener) . As a result, the system executes the code you write in onClick(View) after the user presses the button. The system executes the code in onClick on the main thread.
How do I use onStart on Android?
onStart() When the activity enters the Started state, the system invokes this callback. The onStart() call makes the activity visible to the user, as the app prepares for the activity to enter the foreground and become interactive. For example, this method is where the app initializes the code that maintains the UI.
What is the purpose of setContentView () function?
Actually setContentView() is a method part of android. app. Activity class. It helps to set our content or render our layout on the screen.
What is the use of savedInstanceState in Android?
The savedInstanceState is a reference to a Bundle object that is passed into the onCreate method of every Android Activity. Activities have the ability, under special circumstances, to restore themselves to a previous state using the data stored in this bundle.
What is onResume method in Android?
onResume() is one of the methods called throughout the activity lifecycle. onResume() is the counterpart to onPause() which is called anytime an activity is hidden from view, e.g. if you start a new activity that hides it. onResume() is called when the activity that was hidden comes back to view on the screen.
How do I use onPause in Android?
onPause(): This method gets called when the UI is partially visible to the user. If a dialog is opened on the activity then the activity goes to pause state and calls onPause() method. Here the activity is in the paused state. onStop(): This method gets called when the UI is not visible to the user.
How do I change content view on Android?
1 Answer. You can call setContentView at any time*, not just in onCreate . Just define all the views you want in separate XML files and pass the relevant id when it’s time to switch. If you want to define the new layout dynamically in code, then do that and call setContentView and pass the root view of your new layout.
What is R layout?
In Android R is an Java-class that is auto-generated from your resources by the build process. … layout member is a auto-generated class that contains all IDs for layouts. R. layout. activity_main is a static final int member that represents the ID of the layout-file in layout/activity_main.
What are the two 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. When the application does not name a target component, that it is an implicit intent.
What is the use of intent in android?
Intents are used to signal to the Android system that a certain event has occurred. Intents often describe the action which should be performed and provide data upon which such an action should be done. For example, your application can start a browser component for a certain URL via an intent.
What does Super onCreate do?
By calling super. onCreate(savedInstanceState); , you tell the Dalvik VM to run your code in addition to the existing code in the onCreate() of the parent class. If you leave out this line, then only your code is run. … In short, Android’s own classes can be incredibly complex.
What is the use of onCreate method in Android?
onCreate(Bundle) is where you initialize your activity. When Activity is started and application is not loaded, then both onCreate() methods will be called. But for subsequent starts of Activity , the onCreate() of application will not be called.
What does finish () do in Android?
Finish() method will destroy the current activity. You can use this method in cases when you dont want this activity to load again and again when the user presses back button. Basically it clears the activity from the. current stack.
Can I create activity without XML file?
If you don’t want Android to Studio to generate the xml files for you, You must do every steps on your own. Create a java class which extends from activity. Override OnCreate method in your activity and set your layout.
What is the use of the setContentView function in an app code?
One has to understand its use completely to work with Android UserInterface. Basically what this function does is display the Layout created thorugh XML or the Dynamically created layout view in the Screen. setContentView() function in main activity is used to attach a layout file to that activity.