Java For Dummies Quick Reference

JLabel Class

Package: javax.swing

The JLabel class represents a label — a user interface component that simply displays text. Labels are used for a variety of purposes: display captions for other controls (such as text fields or combo boxes), informational messages, or results of a calculation or a database lookup.

Constructors

Constructor	Description
JLabel()	Creates a new label with no initial text
JLabel(String text)	Creates a new label with the specified text

Methods

Method	Description
String getText()	Returns the text displayed by the label
void setText(String text)	Sets the text displayed by the label
void setToolTipText (String text)	Sets the tooltip text that displays if the user hovers the mouse over the label for a few moments
void setVisible(boolean value)	Shows or hides the label

When you create a label, you can pass the text you want it to display to the constructor, like this:

JLabel label1 = new JLabel(“Hello, World!”);

Or you can create the label first and then set its text later, as follows:

JLabel label1 = new JLabel();

label1.setText(“Hello, World!”);

To display a label, you must add it to a panel, which in turn must be added to a frame. Here’s an example of a constructor for a frame class that creates a panel, creates a label, adds the label to the panel, and then adds the panel to the frame:

// HelloFrame constructor

public HelloFrame()

{

this.setSize(300,150);

this.setDefaultCloseOperation( ...