1. Abstract classes and abstract functions
1) The definition of an abstract class, plus the keyword abstract before the class, such as:
Abstract class test{}
2) The definition of an abstract function, with the keyword abstract before the function, such as:
Abstract class test{ abstractvoid functoin ();}
2. Abstract functions and characteristics of abstract classes
1) abstract function only function definition no function body, such as the above code, only the definition of functions, but there is no content;
2) If there is one or more abstract functions in the abstract class, then the class must be defined as an abstract class;
3) Abstract class is born to be the parent class (inherited), the subclass of the parent class to replicate the abstract function;
4) Use abstract classes to avoid many errors.
Abstract classes and abstract functions of java4android Basic Learning