Wednesday, 6 November 2013

JLabel Example in Java for Beginners

The following example illustrates JLabel example in Java swing for beginners. This example covers all the core methods of javax.swing.JLabel class.

import javax.swing.*;

import java.awt.*;

class JLabelExample extends JFrame

{

JTextField jt1,jt2;

JLabel l1,l2,l3,l4,l5,l6;

ImageIcon i1,i2,i3,i4,i5;

Font f;



    public JLabelExample()

    {

        createAndShowGUI();

    }

   

    private void createAndShowGUI()

    {

       

        // Set frame properties

        setTitle("JLabel Demo");

        setSize(400,400);

        setLayout(new FlowLayout());

        setVisible(true);

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);



        // Create a font

        f=new Font("Myriad Pro",Font.PLAIN,22);

       

        // Create image icons

        i1=new ImageIcon("icon1.png");

        i2=new ImageIcon("icon2.png");

        i3=new ImageIcon("pictures.png");

        i4=new ImageIcon("finder.png");

        i5=new ImageIcon("picturesdisabled.png");

       

        // Create JTextFields

        jt1=new JTextField(20);

        jt2=new JTextField(20);

       

        // First constructor

        // Takes no parameter

        // JLabel comes with

        // no icon, text and enabled

        l1=new JLabel();

       

        // Second constructor

        // Takes an Icon

        l2=new JLabel(i1);

       

        // Third constructor

        // Takes icon and horizontal alignment

        // of the label

        l3=new JLabel(i2,SwingConstants.CENTER);

       

        // Fourth constructor

        // Takes String text that comes

        // on the JLabel

        l4=new JLabel("Label 4");

       

        // Fifth constructor

        // Takes String text with an icon and horizontal

        // alignment of label

        l5=new JLabel("Label 5",i3,SwingConstants.LEADING);

       

        // Sixth constructor

        // Takes String text with horizontal alignment

        l6=new JLabel("<html><h2>Label <u>6</u></h2></html>",SwingConstants.TRAILING);

       

        // Set some text

        l1.setText("Label 1");

        l2.setText("Label 2");

       

        // Get text

        System.out.println("Text on l1 is "+l1.getText());

        System.out.println("Text on l2 is "+l2.getText());

       

        // Set some font

        l1.setFont(f);

        l2.setFont(f);

       

        // Get font

        System.out.println("Font of l1 is "+l1.getFont());

        System.out.println("Font of l2 is "+l2.getFont());

       

        // Set icon

        l4.setIcon(i4);

       

        // Set icon text gap

        // Default value is 4

        // This is relative to

        // the alignment

        l4.setIconTextGap(8);

       

        // Get icon text gap

        System.out.println("Icon text gap for l4 is "+l4.getIconTextGap());

       

        // Set mnemonic

        // When user presses this key

        // with alt pressed, requestFocus()

        // is called on the corresponding

        // label

        l1.setDisplayedMnemonic('1');

        l2.setDisplayedMnemonic('2');

        l6.setDisplayedMnemonic((int)'6');

       

        // Get displayed mnemonics

        System.out.println("Displayed mnemonic for l1 is "+l1.getDisplayedMnemonic());

        System.out.println("Displayed mnemonic for l2 is "+l2.getDisplayedMnemonic());

        System.out.println("Displayed mnemonic for l5 is "+l6.getDisplayedMnemonic());

       

        // Set displayed mnemonic index

        // The character at this index

        // in JLabel will be underrlined

        //l6.setDisplayedMnemonicIndex(16);

       

        // Set vertical text position

        l4.setVerticalTextPosition(SwingConstants.BOTTOM);

       

        // Get vertical text position

        System.out.println("Vertical text position for l4 "+l4.getVerticalTextPosition());

       

        // Set horizontal text position

        l4.setHorizontalTextPosition(SwingConstants.CENTER);

       

        // Get horizontal text position

        System.out.println("Horizontal text position for l4 "+l4.getHorizontalTextPosition());

       

        // Now the text on l4 will appear

        // below the icon (vertical) and at

        // the center looks pretty much like desktop icon

       

        // Set label for some component.

        // Whenever the user fires the mnemonic

        // requestFocus() is called on the component

        // associated with the label provided that

        // the component is focusable

        // Otherwise, focus gets transferred to the

        // label itself

        l1.setLabelFor(jt1);

        l6.setLabelFor(jt2);



        // Set some background,foreground

        // to make alignment visible

       

        // Before setting background,

        // JLabel must be made opaque

        // By default isOpaque() returns false

       

        // Set opaque

        l6.setOpaque(true);

       

        // Print is opaque

        System.out.println("l6 is "+(l6.isOpaque()?"opaque":"not opaque"));

       

        // Set background,foreground

        l6.setBackground(Color.DARK_GRAY);

        l6.setForeground(Color.WHITE);

       

        // Get background,foreground

        System.out.println("Background for l6 is "+l6.getBackground());

        System.out.println("Foreground for l6 is "+l6.getForeground());

       

        // Also increase size

        l6.setPreferredSize(new Dimension(100,50));

       

        // Get preferred size

        System.out.println("The preferred size of l6 is "+l6.getPreferredSize());

       

        // Set vertical alignment

        l6.setVerticalAlignment(SwingConstants.TOP);

       

        // Get vertical alignment

        System.out.println("Vertical alignment of l6 is "+l6.getVerticalAlignment());

       

        // Set horizontal alignment

        l6.setHorizontalAlignment(SwingConstants.RIGHT);

       

        // Get horizontal alignment

        System.out.println("Horizontal alignment of l6 is "+l6.getHorizontalAlignment());

       

        // Disable l5

        l5.setEnabled(false);

       

        // is enabled

        System.out.println("l5 is "+(l5.isEnabled()?"enabled":"disabled"));

       

        // The icon is also greyed out

        // Alternatively, one can also

        // set disabled icon

        l5.setDisabledIcon(i5);

       

        // Add all components

        add(l1);

        add(jt1);

        add(l2);

        add(l3);

        add(l4);

        add(l5);

        add(l6);

        add(jt2);

    }   

   

    public static void main(String args[])

    {

        SwingUtilities.invokeLater(new Runnable(){

            public void run()

            {

                new JLabelExample();

            }

        });

    }

}

Screenshot of JLabel Example
 

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