Responding to Events Event Handling in Java Making the UI Work Responding to Events Event Handling in Java

Event Handling Event Handling Consist of the following 3 things Events Event Sources / Generators Event Listeners / Handlers 3/19/2008 11:06:58 PM Property of N++ Studios

Event An action which is recognized by an object is known as an Event For example. Moving the mouse pointer over button and clicking over the button Specific Event Listeners are available for handling specific events. 3/19/2008 11:06:58 PM Property of N++ Studios

Some Events, ActionEvent ItemEvent AdjustmentEvent KeyEvent Such as mouse clicks and Enter key presses ItemEvent Such as selecting an item from a dropdown list box AdjustmentEvent Such as moving a scrollbar KeyEvent Such as pressing a key on the Keyboard 3/19/2008 11:06:58 PM Property of N++ Studios

Event Sources / Generators Components which can generate the events are commonly known as event sources or event generators. Examples Button Scrollbar Checkbox Choice TextField 3/19/2008 11:06:58 PM Property of N++ Studios

Event Listeners / Handlers These are special kind of java Interfaces (type of java program) that is used to handle the events. Each Listener is built with one or more methods to respond to event, Before these Listeners can handle the events for you, you must register the components with the relevant Event Listener refer the code samples for more information. 3/19/2008 11:06:58 PM Property of N++ Studios

Question (s) Create an UI with two buttons, when you click on the first button the second button’s position should change. Create an UI to enter a number and display in a label EVEN or ODD with 2 different colors Create an UI with two TextFields and one button once you type something in the TextField and click the button count the number of characters in the 1st textfield and display it in the 2nd TextField. 3/19/2008 11:06:58 PM Property of N++ Studios