What is the difference between Views and widgets?

Question

If I am not wrong, View is the superclass for all widgets, but how do I differentiate between a View and a widget? For example, a button or a text box, what sho

Answer 1

widgets are the views which resides (shown to user) outside the app, to perform the specific functions (launching the main app itself or providing a feature of the app itself) without needing to launch the app instead.
e.g a clock widget shows you the time without launching the Alarm or Time application.

A more precise definition can be found at :
Definition of widgets

Answer 2

As is elegantly stated in the View class docs:

This class represents the basic building block for user interface components. A View occupies a rectangular area on the screen and is responsible for drawing and event handling. View is the base class for widgets, which are used to create interactive UI components (buttons, text fields, etc.). The ViewGroup subclass is the base class for layouts, which are invisible containers that hold other Views (or other ViewGroups) and define their layout properties.

Therefore a View is a base class for IU elements and a Widget is loosely defined as any ready to use View. In particular though:

View: A View is a base class for all UI elements. It therefore covers many different classes and concepts, including Widgets, ViewGroups and Layouts. There is a root View attached to a Window instance which forms the basis of the View hierarchy. In general, the word View is usually used to describe UI elements in general, or to refer to abstract or base UI classes such as ViewGroups.

Widget: There are various definitions for this term, but most refer to a 'ready to use' UI element, be it a Button, ImageView, EditText, etc. Note that some people consider Widgets to be UI elements that are complete (not abstract) and are not containers (such as ViewGroups (Layouts/ListViews). It's also worth noting that Widget is a package name (android.widget) where the docs mention the following:

The widget package contains (mostly visual) UI elements to use on your Application screen.

Therefore it is reasonable to consider non visual UI elements to also be Widgets, as well as any class defined under the widget package. See here for a full list of classes in the widget package: http://developer.android.com/reference/android/widget/package-summary.html

App Widget: Not to be confused with a UI element widget, an App Widget is a remote View hierarchy which is most commonly displayed on the user's home screen. As defined by the docs:

App Widgets are miniature application views that can be embedded in other applications (such as the Home screen) and receive periodic updates. These views are referred to as Widgets in the user interface, and you can publish one with an App Widget provider. An application component that is able to hold other App Widgets is called an App Widget host.

ViewGroup: A ViewGroup is a subclass of View and provides the ability to parent and position child Views such as in the case of Layouts.

Layout/View Containers: Much as with Widgets, there is no Layout base class and it is therefore could be loosely defined as any class which extends ViewGroup and provides the ability to define the positioning of child Views within it. Usually only ViewGroup subclasses which are appended with the world Layout (as in LinearLayout, RelativeLayout) are referred to as Layouts, other classes extending ViewGroup are usually just referred to as View Containers.

Finally, I'd like to suggest that whenever you mention Views, Widgets or any other important term, to make clear your intended definition so that people can better understand what you're referring to.

For further reading: what is the difference between views and widgets difference between view and widget

Answer 3

Think of view as something like a huge container that contains anything which occupies a rectangular area on screen and handles drawing and event handling.

While widgets are a set of Pre-built views that can be used to construct a user interface ,e.g buttons,Checkbox,EditText. Widgets are a subset of views.

Answer 4

Calling them either is fine.

I tend to use the term "widget" for subclasses of View that have a visual representation to the user by default -- things like TextView, Button, ListView, etc.

I tend to use the term "view" for something that could be any subclass of View, including pure containers like LinearLayout.

But, again, there is no particular harm in referring to them by either term.

Answer 5

A view is the basic building block for UI components. Think of a View as a rectangle on the screen that can draw itself and handle events.(1)

So, there is no implicit "semantic" associated with a View. You can essentially implement anything that appears on the screen and interacts with the user.

Now, a widget is what you typically think about as a "control" through which the user interacts with your application. A button, a spinner and a checkbox are all good examples of "widgets". However, this is not a "hard" definition and there is no such thing as a Widget class on Android. The fact that something is a "widget" merely means the class is in the android.widgets package for organizational purposes, but it is, in fact, a View.

For example, a Button's base class is View, not something like android.widgets.Widget (which does not exist).

(1) http://developer.android.com/reference/android/view/View.html

See also: http://developer.android.com/reference/android/view/package-summary.html
http://developer.android.com/reference/android/widget/package-summary.html