Create custom widgets and controls

Creating new views gives you the power to fundamentally change the appearance and feeling of an application. By creating your own controls, you can create a unique UI that suits your user needs. Create a new control from an empty canvas. You need to extend the View class or surfaceview class.

 

The View class provides a canvas object, some draw methods, and painting class. It uses screen graphics technology to create a visual interface. Then, you can override user events, such as screen touch or press the button to provide interactivity. The view base class provides a lightweight solution without the need for extremely fast re-painting and 3D graphics.

 

The surfaceview class provides a canvas that can be drawn in background threads and can be used to create 3D images. It is an excellent choice for controls that quickly update or display complex graphic information (especially game and 3D vision.

 

This chapter describes 2D controls based on The View class. For more information about the surfaceview class and advanced canvas painting features in Android, see Chapter 11th.