The term UI stands for ‘User Interface’. All the user interface in elements in Android platform are built with two main objects:
- View : It is a object that draws something on screen with which a user can interact.
- ViewGroup : It is an object that holds View object in order to get the best interface layout.
Android library has wide range of both ViewGroup and View and their sub-classes that also provides various input controls like types of buttons, space field, text boxes etc. They also provide us with various layout models such as relative and linear.
Layout of UI
The client interface for every segment of your Android app development is characterized using a progression of View and Viewgroup objects, as demonstrated in figure.
Every viewGroup is an undetectable holder or say container that sorts out child view first, while the child view may be include controls or different gadgets that draw some piece of the UI. This order tree could be as basic or perplexing as you need it to be. It is always suggest to keep the design as simple as possible because simple designs work and execute at faster pace.
To proclaim your design, you can easily instantiate View objects in your code and begin building a tree, yet the most effortless and best approach to characterize your format is with a XML language. XML offers a comprehensible structure for the design, like HTML.
The name of a XML component for a View is to the Android class with it reports to. So a <textview> element makes a Textview gadget in your UI, and a <linearlayout> component makes a Linearlayout perspective gathering.
Client Interface Components
You really don’t need to build the greater part of your UI utilizing View and Viewgroup objects. Android gives a few application segments that offer a standard UI design for with which you essentially need to characterize the substance. These UI parts each one have an exceptional set of APIs that are depicted in their individual reports, for example, Action Bar, dialog boxes, text fields and Status Notifications.