Skip to main content

Role of Basic Graphical Controls of Programming: Introduction to Java

The Palette tab of a Graphical controls offered by Java Swing contains the tools that you can use to draw controls on your forms/windows/ frames while programming. The area on the frame where GUI components are placed is called content pane.

Role of Basic Graphical Controls of Programming: Introduction to Java

In earlier article, we have discussed about what are components. You have seen many controls listed on the Swing control palette. Here’s a list with briefly description about role and purpose of some commonly used controls.

  • JFrame provides the basic attributes and behavior of a window. A frame is displayed as a separate window with its own tittle bar.
  • JLable allows un-editable text (i.e., that user cannot change) or icons to be displayed.
  • JTextField allows user input, can also be used to be display text. As it can be edited you can also call it edit field.
  • JButton provides button capabilities. An action Event is generated when button is pushed.
  • JCheckBox provides check box. Checkboxes are used to allow a user select multiple choices, e.g., a student can select 5 subject out of 17 subject-choices. A check boxes shows an X in box in front of it when selected.
  • JList is a list of items from which a selection can be made. From a list, multiple elements can be selected.
  • JComboBox provides a drop-down list of items from which a selection can be made or new items can be added. It is a combination of text field and list.
    Note: The area on the frame where GUI components are placed is called content pane.
  • JPanel is a supporting container that cannot be displayed on its own but must be added to another container. Panels can be added to the content pane of a frame. They help to organize the components in a GUI.
  • JRadioButton provides radio buttons. Radio buttons are option buttons that can be turned on or off. The radio buttons provide mutually exclusive options.

Note: Though radio buttons and checkboxes appear to function similarly, yet there is an important difference-when a radio button is selected, all other radio buttons in its same group are automatically unselected. On the other hand, any no. of checkboxes can be selected.


Popular posts from this blog

difference between structure and union in C Language

In c language article we will see the difference between union and structure. Both are the user define datatype in c language. See the table which is mentioned below: ASP.NET Video Tutorial Series Structure Union1.The keywordstruct is used to define a structure 1. The keyword union is used to define a union. 2. When a variable is associated with a structure, the compiler allocates the memory for each member. The size of structure is greater than or equal to the sum ofsizes of its members. The smaller members may end with unused slack bytes. 2. When a variable is associated with a union, thecompiler allocates thememory by considering the size of the largest memory. So, size of union is equal to the size of largest member. 3. Each member within a structure is assigned unique storage area of location. 3. Memory allocated is shared by individual members of union. 4. The address of each member will be in ascending order This indicates that memory for each member will start at different offset v…

Difference between Linear search and Binary Search in c language

SQL Video Channel : Download all SQL Video

Binary Search Linear Search Works only on sorted items. such as  1,2,3,4,5,6  etc
Works on sorted as well as unsorted items. 12,4,5,3,2,1 etc Very efficient if the items are sorted Very efficient if the items are less and present in the beginning of the list. such as Suppose your list items are : 12,3,4,5,1 and you want to search 12 number then you get beginning in the list. Works well with arrays and not on linked lists. Works with arrays and linked lists.
Number of comparisons are less More number of comparisons are required if the items are present in the later part of the array or its elements are more.

Memory representation of Linked List Data Structures in C Language

Memory representation of Linked List

             In memory the linked list is stored in scattered cells (locations).The memory for each node is allocated dynamically means as and when required. So the Linked List can increase as per the user wish and the size is not fixed, it can vary.

               Suppose first node of linked list is allocated with an address 1008. Its graphical representation looks like the figure shown below:

      Suppose next node is allocated at an address 506, so the list becomes,

  Suppose next node is allocated with an address with an address 10,s the list become,

The other way to represent the linked list is as shown below:

 In the above representation the data stored in the linked list is “INDIA”, the information part of each node contains one character. The external pointer root points to first node’s address 1005. The link part of the node containing information I contains 1007, the address of next node. The last node …