Which method is invoked when the activity is started?

Which method is invoked when the activity is started?

onCreate

Which method is used to call another activity when we expect to get something back from the called activity?

Android StartActivityForResult Example

Which method from the Activity class matches the following description Called when the activity is becoming visible to the user followed by onResume () if the activity comes to the foreground?

If the activity becomes visible to the user again, the onRestart() method gets called, followed by onStart() and onResume().

What is an activity How do you create an activity?

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. The Activity class defines the following call backs i.e. events. You don’t need to implement all the callbacks methods.

Which of the following activity life cycle methods is called once the activity is no longer visible?

onStop(): Called when you are no longer visible to the user.

How do you call a class in Android activity?

public class MainActivity extends AppCompatActivity { // Instance of AnotherClass for future use private AnotherClass anotherClass; @Override protected void onCreate(Bundle savedInstanceState) { // Create new instance of AnotherClass and // pass instance of MainActivity by “this” anotherClass = new AnotherClass(this); …

How do you declare activity in manifest?

To declare your activity, open your manifest file and add an <activity> element as a child of the element. For example: <manifest > The only required attribute for this element is android:name, which specifies the class name of the activity.

What should service manifest declare?

You declare a service in your app’s Manifest, by adding a <service> element as a child of your element. There’s a list of attributes that you can use to control a service’s behavior, but as a minimum you’ll need to provide the service’s name (android:name) and a description (android:description).

What is the difference between activity and view in Android?

View is Display System of Android where you define layout to put subclasses of View in it eg. Buttons, Images etc. But Activity is Screen System of Android where you put display as well as user-interaction,(or whatever which can be contained in full-screen Window.)

How many types of activity are there in Android?

Three of the four component types—activities, services, and broadcast receivers—are activated by an asynchronous message called an intent. Intents bind individual components to each other at runtime.

How do you pass intent?

Intent intent = new Intent(getApplicationContext(), SecondActivity. class); intent. putExtra(“Variable name”, “Value you want to pass”); startActivity(intent); Now on the OnCreate method of your SecondActivity you can fetch the extras like this.

What is Android default activity?

In Android, you can configure the starting activity (default activity) of your application via following “intent-filter” in “AndroidManifest. xml“. See following code snippet to configure a activity class “logoActivity” as the default activity.

How do I set default activity?

Go to AndroidManifest. xml in the root folder of your project and change the Activity name which you want to execute first. If you are using Android Studio and you might have previously selected another Activity to launch. Click on Run > Edit configuration and then make sure that Launch default Activity is selected.

Is it possible to create an activity in Android without a user interface?

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.

How does Android define intent?

An intent is to perform an action on the screen. It is mostly used to start activity, send broadcast receiver,start services and send message between two activities. There are two intents available in android as Implicit Intents and Explicit Intents.

What are the two types of intent?

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 activity and intent in android?

An activity is started or activated with an intent. An Intent is an asynchronous message that you can use in your activity to request an action from another activity, or from some other app component. You use an intent to start one activity from another activity, and to pass data between activities.

What are the different types of layouts in Android?

Common Layouts

• Linear Layout. A layout that organizes its children into a single horizontal or vertical row.
• Relative Layout. Enables you to specify the location of child objects relative to each other (child A to the left of child B) or to the parent (aligned to the top of the parent).
• Web View.
• List View.
• Grid View.

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.

Which is best layout in Android?

Use FrameLayout, RelativeLayout or a custom layout instead. Those layouts will adapt to different screen sizes, whereas AbsoluteLayout will not. I always go for LinearLayout over all other layout.

Which layout is faster in Android?

Results show that the fastest layout is Relative Layout, but difference between this and Linear Layout is really small, what we can’t say about Constraint Layout. More complex layout but results are the same, flat Constraint Layout is slower than nested Linear Layout.

Where are layouts placed in Android?

folder reslayout

Should I use constraint layout?

Android Studio provides us with the number of layouts and it might be a bit confusing to choose the most suitable one for your job. Well, each layout has its own benefits but when it comes to complex, dynamic and responsive views you should always choose Constraint Layout.

What is the advantage of constraint layout?

This is because ConstraintLayout allows you to build complex layouts without having to nest View and ViewGroup elements. When running the Systrace tool for the version of our layout that uses ConstraintLayout , you see far fewer expensive measure/layout passes during the same 20-second interval.

What is constraint layout?

A ConstraintLayout is a android. view. ViewGroup which allows you to position and size widgets in a flexible way. Note: ConstraintLayout is available as a support library that you can use on Android systems starting with API level 9 (Gingerbread).

What is the difference between constraint layout and relative layout?

Constraint Layout has dual power of both Relative Layout as well as Linear layout: Set relative positions of views ( like Relative layout ) and also set weights for dynamic UI (which was only possible in Linear Layout). A very powerful use is grouping of elements by forming a chain.