Question: What Is The Purpose Of SetContentView () Function?

Where are layouts placed in Android?

In Android, an XML-based layout is a file that defines the different widgets to be used in the UI and the relations between those widgets and their containers.

Android treats the layout files as resources.

Hence the layouts are kept in the folder reslayout..

What is the purpose of setContentView () function write its parameters?

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.

What is FindViewById () method used for?

FindViewById Method (Android….Overloads.FindViewById(Int32)Finds a view that was identified by the id attribute from the XML that was processed in OnCreate(Bundle).FindViewById(Int32)Finds a view that was identified by the id attribute from the XML layout resource.

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 is the use of the setContentView function in an app code?

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 setContentView in Android?

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).

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.

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.

What are the 4 types of app components?

There are four different types of app components:Activities.Services.Broadcast receivers.Content providers.

How can I make my Android UI smoother?

Measure overall UI performance with Systrace to get a baseline. Use Hierarchy Viewer to identify and flatten view hierarchies. Reduce overdraw by flattening layouts and drawing less pixels on screen. Enable StrictMode to identify and make fewer potentially blocking calls on the main UI thread.

Which Android layout is best?

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.

How do you kill an activity?

9 Answers. You can also add android:noHistory=”true” to your Activity tag in AndroidManifest. xml . Yes, all you need to do is call finish() in any Activity you would like to close.

What is the use of onCreate method in Android?

onCreate() On activity creation, the activity enters the Created state. In the onCreate() method, you perform basic application startup logic that should happen only once for the entire life of the activity.

How do I use onStart on Android?

onStart()When activity start getting visible to user then onStart() will be called.This calls just after the onCreate() at first time launch of activity.When activity launch, first onCreate() method call then onStart() and then onResume().If the activity is in onPause() condition i.e. not visible to user.

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. net.

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.

Which layout is faster in Android?

Layout with 2 views on different sides. 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.

Which method is called when app is killed android?

1. You need to save your data when on onPause() is called. Look at this life cycle diagram: Android Developer. You can see that an app can be killed after onPause() or onStop() . Handle your data there and recover it in onRestart() \ onCreate() .