Logo F2FInterview

Swing Interview Questions

Q   |   QA

The dragging and dropping for an empty table allows it to be portable and the data can be moved with ease. The steps that are followed for this is:

  • The creation of an empty table that is used to get some data and the insertion gets performed in using the database techniques.
  • After creation of an empty table then the creating and attaching of the TransferHandler class gets included that allow the proper transfer of the data from one place to another. It also handles the interrupts that may occur while transferring the data.
  • Enable the data transfer to allow the calling of the object setDragEnabled(true). When this value is set to true then the table can be draggable and the data can be moved.
  • Creation of the scroll pane takes place to allow the adding of the table so that it can be dragged from one pane to another pane with ease and comfort. 

TransferHandler class is used for data transfer and it provides an easy way to transfer the data from the Jcomponent. All the details of the data are contained in the class and it support the classes as well. Components are provided with the default handler that can create own handler of their own. There are three methods that can be used to use theTransferHandler on a component and these are as follows:

  • setDragEnabled(boolean)- this turn the drag support that is given as false and it defines the component that support the drag facility that links to the list given by Jlist.
  • setDropMode(DropMode)- is used to configure the drop locations and determine the use of Jlist, Jtable, Jtree.
  • setTransferHandler(TransferHandler)- is used to allow the plug in data to be imported or exported by using the Jcomponent that is defined for it.

Action is performed on a state to allow it to change. It defines the interface that it is implementing. The library that is used for the action interface is javax.swing.Action. This action interface extends the ActionListener interface class that is being provided from the AWT. Action interface allow the concrete classes to implement the actionPerformed() method and provide the action that is associated with it. The use of actionPerformed() method allow the implementation of the behavior that is desired in the programming and allow it to show the functionality of the action class. The action can be added to the container class that accepts the parameters on an event like JMenu, JPopupMenu, or JtoolBar. The container used in this automatically registers the action that is taken on the event and it acts as an ActionListener of the user interface.

AbstractAction class allows the implementation of the abstract functions and the action interfaces. AbstractAction provides with the default functionality that are provided with the methods in the Action interface. The action can extend the class to create some specific actions for the users. The methods that is provided to implement the actionPerformed() method and it is used to provide the overall functionality for the action. ActionEvent is used to show the action command that can be used to add some features of the contents and provide ready to use action functionality on the event that can be carried for all the user interface fields.

class MyAction extends AbstractAction
{ }
public MyAction(String text, Icon icon)
{ super(text,icon); }
public void actionPerformed(ActionEvent e)
{ System.out.println("Action ["+e.getActionCommand()+"]!"); } 

Jcomponent is used as an abstract class that extends the functionality of the swing components. It allows the common swing component library to get involved in providing the functionality and the visual appearance that is required. The class that serves this purpose is given as: java.awt.Component class. This class also provides the framework for AWT components as well. The other class javax.swing.JComponent provides the role that is identical to other classes for the Swing components. JComponent class extends the class java.awt.Container that itself extend another class of java.awt.Component. This allows the AWT functionality to be used and added while writing the code for a program that needs to be executed. Jcomponents uses the swing component and allow the containers to handle the request for all the components like add() the component in the container, etc.

In order to link this F2FInterview's page as Reference on your website or Blog, click on below text area and pres (CTRL-C) to copy the code in clipboard or right click then copy the following lines after that paste into your website or Blog.

Get Reference Link To This Page: (copy below code by (CTRL-C) and paste into your website or Blog)
HTML Rendering of above code: