JLabel

You can use the JLabel class to display text and images. A label exist to display information to the user and so a JLabel is uneditable. There are five constructors to choose from when creating a label.

`JLabel(String s)`	creates a label with text displayed
`JLabel(String s, int position)`	creates a label and justifies the text according to `position`.
`JLabel(Icon m)`	an image is shown on the button
`JLabel(Icon m, int position)`	creates an label showing an image and justifies the image according to `position`.
`JLabel(String s, Icon m, int position)`	creates a label showing text and an image, justified according to `position`.

Values you can use when a position argument is expected are:-

JLabel.LEFT

JLabel.RIGHT

JLabel.Center

The value of position you choose affects the relative alignment of the text and image within the painting area of the label.

Plain JLabel

To create a plain label, use a line of code such as:-

JLabel aLabel = new JLabel(" I am a plain label");

To create a plain label, with a specific text alignment use a line of code such as:-

JLabel aLabel = new JLabel(" I am a plain label", JLabel.LEFT);

JLabel aLabel = new JLabel(" I am a plain label", JLabel.RIGHT);

JLabel aLabel = new JLabel(" I am a plain label", JLabel.CENTER);

Note: -- You will only see a change in the alignment of text within the label if the label's painting area is larger than the text within the label. The painting area may be the exact dimensions of the text, in which case, the alignment value will appear to do nothing.

For example, if a label is added to the content pane of an applet window, the painting area of the label takes up the whole area of the applet's content pane. The label shown below is drawn the exact width of the applet window's content pane. The label was drawn with a border around it to show you the painting area.

If a label is added to a panel, the label's painting area is the exact size it needs to be to display it's contents.

JLabel with Image

To create a label with an image we need to create an Icon. We can use the ImageIcon class for this:-

ImageIcon anIcon = new ImageIcon ("spiral.gif");

then we can use that variable that references the ImageIcon object in the argument for the label's constructor:-

JLabel aLabel = new JLabel(anIcon);

Alternatively, if we don't need a variable that references the ImageIcon object we could use a single line of code as follows:-

JLabel aLabel = new JLabel(new ImageIcon ("spiral.gif"));

Don't forget to place your image file in the same folder as you class file.

Important: -- Using images in applets? Then read this and instead of creating a new ImageIcon instance with the line:-

ImageIcon anIcon = new ImageIcon ("spiral.gif");

We would use:-

ImageIcon anIcon = new ImageIcon (getImage(getCodeBase(),"spiral.gif"));

You must also import an extra package:-

import java.net.*

To create a label, with a specific image alignment use a line of code such as:-

JLabel aLabel = new JLabel(new ImageIcon ("spiral.gif"), JLabel.RIGHT);

This will place the image on the right side of the label's painting area. You can also use JLabel.LEFT and JLabel.CENTER.

Note: -- You will only see a change in the alignment if the label's painting area is larger than the text within the label. The painting area may be the exact dimensions of the text, in which case, the alignment value will appear to do nothing. See the note above for more details.

JLabel with Image & Text

To create a label that displays both text and an image, use a line of code such as:-

JLabel aLabel = new JLabel("I am a label with an image and a caption"

new ImageIcon ("spiral.gif"), JLabel.LEFT);

If you are writing an applet, you should use these lines instead:-

ImageIcon anIcon = new ImageIcon (getImage(getCodeBase(),""spiral.gif""));

JLabel aLabel = new JLabel

("I am a label with an image and a caption", anIcon, JLabel.LEFT);

and include the following package:-

import java.net.*

Don't forget to place your image file in the same folder as you class file.

Note: -- The alignment values JLabel.LEFT, JLabel.RIGHT and JLabel.CENTER position the image and text relative to the painting area of the label. You will only see a change in the alignment if the label's painting area is larger than the contents of the label. The painting area may be the exact dimensions of the label's contents, in which case, the alignment value will appear to do nothing.

~Now try the activity~

Activity A

Create an applet with one label added to the applet's content pane. The label should display both a text and an image, (right-aligned.)

Now change and recompile your code so that the image and text is center-aligned.

Now change and recompile your code so that the label is added to a panel which is added to the content pane of the applet. Is there any observable change in the way the label is painted?

Note: You can use my image file if you wish or find a gif of your own.

Other JLabel Methods

Here are some methods we can use with the JLabel class. You should note that this is not a full list, there are lots of other methods. You should also check out the inherited JComponent class methods.

setText(String s)
getText()

Set or get the text displayed by the label.

setHorizontalTextPosition(int i)

Set the horizontal position of the label's text relative to the label's image using as the argument: JLabel.LEFT, JLabel.CENTER or JLabel.RIGHT.

setVerticalTextPosition(int i)

Set the vertical position of the label's text relative to the label's image using as the argument: JLabel.TOP, JLabel.CENTER (the default), and JLabel.BOTTOM.

~Now try the activity~

Activity B

Using the applet you created for activity A and using appropriate methods from the JLabel and JComponent class ...

Set the image position to the right of the text in the label.

Set the font color of the label to any color of your choice, (apart from black).

Set the font to Arial, bold, italic and 14 points in size. The Font class is explained in the Graphics tutorial.