What is the use of findViewById in Android?

findViewById connects your backend code with the User Interface elements, layouts, buttons, etc. Every component in the user interface has an ID associated with it, which allows you to control its actions from backend.

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Also know, what is findViewById?

R is a Class in android that are having the id's of all the view's. findViewById is a method that finds the view from the layout resource file that are attached with current Activity.

Also Know, what is the use of Requestfocus in Android? Request focus is used to set automatically keypad function on edittext box so just after activity starts it will automatically select defined Requestfocus editText and open keypad so application user can directly insert data into editText box.

Similarly one may ask, what are views in Android?

View is a basic building block of UI (User Interface) in android. A view is a small rectangular box which responds to user inputs. Eg: EditText , Button , CheckBox , etc.. ViewGroup is a invisible container of other views (child views) and other viewgroups.

What is the return type of the function findViewById int id?

As mentioned by @Jon Skeet in comments, findViewById(int id) method returns view(not subviews) in general, but this method is generic and can returns subviews if the compiler knows the type of target class, so in this case, casting is redundant, but in the case that, the type of target class is unconstrained, you have

39 Related Question Answers Found

What is edit text in Android?

In Android, EditText is a standard entry widget in android apps. It is an overlay over TextView that configures itself to be editable. EditText is a subclass of TextView with text editing operations. We often use EditText in our applications in order to provide an input or text field, especially in forms.

What is a layout in Android?

A layout defines the visual structure for a user interface, such as the UI for an activity or app widget. You can declare a layout in two ways: Declare UI elements in XML. Android provides a straightforward XML vocabulary that corresponds to the View classes and subclasses, such as those for widgets and layouts.

What is FrameLayout Android?

FrameLayout is designed to block out an area on the screen to display a single item. Generally, FrameLayout should be used to hold a single child view, because it can be difficult to organize child views in a way that's scalable to different screen sizes without the children overlapping each other.

What is clickable in Android?

Certain View types, like Button , are denoted as clickable by default. In your app, if the View is not clickable, or does not perform an action when clicked, remove its OnClickListener or set android:clickable="false" .

How do I use OnClickListener?

Android OnClickListener Example

Create a new Android Project. Open Eclipse IDE and go to File -> New -> Project -> Android -> Android Application Project.
Create the main layout of the Application. Open res/layout/main.xml file :
Code. Now we have to write the code of the application.
Run the application.
Define the onClick method in main.

What is Android offset?

Generally speaking, Offsets can be interpreted in two ways: As representing a point in Cartesian space a specified distance from a separately-maintained origin. For example, the top-left position of children in the RenderBox protocol is typically represented as an Offset from the top left of the parent box.

What is setOnClickListener in Android?

One of the most usable methods in android is setOnClickListener method which helps us to link a listener with certain attributes. setOnClickListener is a method in Android basically used with buttons, image buttons etc. You can initiate this method easily like, public void setOnClickListener(View.OnClickListner)

What is a TextView in Android?

In android, TextView is a user interface control which is used to set and display the text to the user based on our requirements. In android, we can create a TextView control in two ways either in XML layout file or create it in Activity file programmatically.

What are the different types of view?

There are 2 types of Views in SQL: Simple View and Complex View. Simple views can only contain a single base table. Complex views can be constructed on more than one base table. In particular, complex views can contain: join conditions, a group by clause, a order by clause.

How many types of layouts are there in Android?

Let's see what are the main Layout Types in designing Android app.

What is a Layout ?
Layouts structure.
Linear Layout.
Relative Layout.
Table Layout.
Grid View.
Tab Layout.
List View.

How do you create a list view?

How to make a ListView in android?

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.
Step 2 − Add the following code to res/layout/activity_main.xml.
Step 3 − Add the following code to src/MainActivity. java.

What is a widget on Android?

In Android, the word widget is a generic term for a bit of self-contained code that displays a program, or a piece of a program, that is also (usually) a shortcut to a larger application.

What is setContentView?

Answered Nov 23, 2015. setContentView() is a very important function when it comes to programming with Android. 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.

What is difference between fragment and activity?

5 Answers. Activity is an application component that gives a user interface where the user can interact. The fragment is a part of an activity, which contributes its own UI to that activity. but using multiple fragments in a single activity we can create multi-pane UI.

What do you mean by Android?

Android is a mobile operating system developed by Google. It is used by several smartphones and tablets. The Android operating system (OS) is based on the Linux kernel. Unlike Apple's iOS, Android is open source, meaning developers can modify and customize the OS for each phone.

What is r in Android?

Android R. java is an auto-generated file by AAPT (Android Asset Packaging Tool) that contains resource IDs for all the resources of res/directory. If you create any component in the activity_main. xml file, id for the corresponding component is automatically created in this file.

What is an activity in Android?

An Android activity is one screen of the Android app's user interface. In that way an Android activity is very similar to windows in a desktop application. An Android app may contain one or more activities, meaning one or more screens.