JViewLegacy is base class which is used for Joomla View. It includes the methods that are used to display the data or present the data

Subclasses:

 JViewCategories, JViewCategory, JViewCategoryfeed 

Methods: Some of the methods of JViewLegacy are as follows:

• __construct: It's the class constructor which is overridden in the other classes that extends JViewLegacy.
  Syntax:

  __construct(mixed $properties = null) 

  Properties can be an array, variable object etc.
• __toString: It is the magic method that is used to convert object to string.
  Syntax:

  __toString()

• addHelperPath: Add helper script path in LIFO order.

  addHelperPath(mixed $path)

• addTemplatePath: Add view script paths in LIFO order.

  addTemplatePath(mixed $path)

• assign: Assigning variables to view script.

  assign()

• assignRef: Assigning variables by reference to view script.

  assignRef(string $key,  &$val)

  $key is name of variable and &$val is the value.

• def: It is used to assign default value if value is not assigned.

  def(string $property, mixed $default = null)

• display: Used to display template script.

  display(string $tpl = null) 
  

For more please refer the following links:

http://www.phoca.cz/joomla/api/class-JViewLegacy.html

https://api.joomla.org/cms-3/classes/JViewLegacy.html