Swing Components

Here are some basic ones. Refer to the online help to learn about more.

Labels:

Labels are short (1-line) noneditable text objects.
The commonly used methods that belong to the Label class are:
JLabel(String text) - default alignment of LEFT.
JLabel(String text, int align) - align can be JLabel.LEFT, JLabel.RIGHT, or JLabel.CENTER.
getAlignment() - return the Label object's current alignment.
getText() - return the current text for the Label object.
setAlignment(int align) - set the Label object's alignment to align.
setText(String text) - set the text for the Label object to text.

Text

Text objects allow text input and output in your Swing program.
The JTextField class provides a single line of text and the JTextArea class provides a rectanglular area (rows and columns) of text.
The width argument (columns) simply sets the size of the display. It does not affect how many characters can be typed in.
The text classes support the standard text behavior such as selecting with the mouse, delete key, backspace, arrow keys, cut, paste, ...
Both classes are derived from the JTextComponent class, which has many useful methods. Here are a few:
getText() - returns the entire contents of the text object (i.e. what the user typed in.)
setText(String text) - set the contents of the text object. This can be used to re-set a text object to a default value.
setEditable(boolean canEdit) - if canEdit is true, the user can edit the text in the text object.
isEditable() - returns true if the user can edit the text object, false if they cannot.
Here are a few useful methods that belong to the JTextField class:
JTextField(String initText) - create the text field and initialize it to initText.

JTextField(int columns) - columns are "approximate".

setEchoChar(char c) - Show the specified character as the user types instead of the characters they are entering (used for passwords).
Here are a few useful methods that belong to the JTextArea class:
JTextArea(int nrows, int ncols) - create the text area with the specified number of rows and columns.

JTextArea(String initText, int nrows, int ncols) - create the text area with the specified number of rows and columns and initialize it to initText.

appendText(String text) - add text to the end of the text area.

insertText(String text, int pos) - insert text into the character position specified. Note this is not a column position, but an index into the character array in the text area.

Check Boxes

The appearance of a checkbox is platform dependent, but usually shows a square followed by some text.

The user clicks on the square to select or unselect the option and can check or uncheck as many boxes as they wish.

Use the JCheckbox class to create a checkbox.
Here are a few useful methods that belong to the JCheckbox class:

JCheckbox(String text) - create a checkbox with the passed-in text as the label.

JCheckbox(String text, boolean on) - create a checkbox with the passed-in text as the label. If on is true, the the checkbox is selected. If on is false, the checkbox is not selected. (Note this is 1.1 only.)

String getLabel() - returns a string containing the checkbox's label.

boolean getState() - returns true if the check box is selected, false if it is not.

Radio Buttons

A radio button is a group of options that can be checked, but only 1 item can be selected at a time.

The appearance of a radio button is dependent on the look and feel, but usually shows a circle followed by some text.

The user clicks on the circle to select or unselect the option and when one option is selected, the currently selected option becomes unselected.

Radio buttons are created by creating JRadioButton objects and grouping them together with a ButtonGroup.

First create the ButtonGroup and JRadioButton objects:


ButtonGroup    fruitRadioButtons = new ButtonGroup();

JRadioButton applebox = new JRadioButton("apples", true);
JRadioButton orangebox = new JRadioButton("orange", true);

Then add the radio buttons to the button group and add the radio buttons to the layout:


fruitRadioButtons.add(applebox);
fruitRadioButtons.add(orangebox);
getContentPane().add(applebox);
getContentPane().add(orangebox);

Buttons

Use the JButton class to create button.
Here are a few useful methods that belong to the JButton class:
JButton() - create an empty button.

JButton(String text) - create a button labeled with the specified text.

String getLabel() - returns the label for the button.

setLabel(String text) - set the label of the button to the passed-in text.
Don't forget to add the button to the layout.