CIS 35A: Introduction to Java Programming

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Swing

Swing
Labels and text fields
Labels

Two panels that display labels

Common constructors and methods of the JLabel class

Constructor Description
JLabel() Creates a blank label.
JLabel(String) Creates a label with the text specified by the string.
Method Description
getText() Returns the text in this text field as a String.
setText(String) Sets the text in this field to the specified string.

How to work with labels

  • The JLabel class defines a label component that can be used to display text on the panel.
  • If you need to refer to a label in code, you can
    1. assign it to a variable and then add that variable to the panel or
    2. create the label and add it to the panel in a single statement.

A class that creates the Label One panel

class LabelPanel extends JPanel
{
    private JLabel labelOne;

    public LabelPanel()
    {
        labelOne = new JLabel("Label One");
        this.add(labelOne);
    }
}

A class that creates the Future Value panel

class FutureValuePanel extends JPanel
{
    public FutureValuePanel()
    {
        this.setLayout(new FlowLayout(FlowLayout.RIGHT));
        this.add(new JLabel("Monthly Payment:"));
        this.add(new JLabel("Yearly Interest Rate:"));
        this.add(new JLabel("Number of Years:"));
        this.add(new JLabel("Future Value:"));
    }
}

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