callback function Tutorial (i): callback function definition and an instance implemented with an interface

callback function Definition:

Pass a function A to another function B, and this function B executes function A. Let's just say that function A is called a callback function. If there is no name, it is called an anonymous callback function. Or pass a method object A to another method object B, and let the latter execute a at the appropriate time, then a is called a callback function.

The callback function instance understands:

Firemen give a phone number 119 (which everyone knows, 119 is equivalent to an interface in Java), and each place has a fire detection device, if the danger to people's lives, then the public can be 119 to the firemen call, Then call a fireman to handle it. The callback means that the fireman gave us a fire call and we could use this number to call the firemen in the event of a fire, but it was not us who dealt with the problem, but the firemen. We are the equivalent of a feedback, only responsible for the firemen feedback information, and ultimately the handler is a fireman.

The code is as follows:

1. Define the callback interface and the method that will be executed in the callback, that is, the method of dialing a distress call.

Public interface Mycallback {       void call ();        

2. Define a class that can operate on the callback interface

public class Caller {       private mycallback mycallback;            public void Docall () {          mycallback.call ();     }        public void Setmycallback (Mycallback mycallback) {          this.mycallback = mycallback;      }        }  

3. Instantiate a specific callback function, implement a callback method, tell the fireman to fire the fire

public class Callbacktest {public      static void Main (string[] args) {                    Caller Caller = new Caller ();                Caller.setmycallback (New Mycallback () {              @Override public              Void Call () {                  System.out.println (' help ');              }          });                    Caller.docall ();      }        }  

callback function Tutorial (i): callback function definition and an instance implemented with an interface