JComboBox: adding automatic completion-Catching user input : ComboBox « Swing Components « Java
JComboBox: adding automatic completion-Catching user input
//Code from: http://www.orbital-computer.de/JComboBox/
/*
Inside JComboBox: adding automatic completion
Author: Thomas Bierhance
thomas@orbital-computer.de
*/
/*
Catching user input
Although there are possibly many ways to catch the input to a text component, only one is
shown here. It is the same that once has been suggested by Sun's Java Tutorial to add
validation to text components (replaced by JFormattedTextField ). It suggests to get control
over the user input by implementing a specialized Document overriding the methods
insertString and remove. Input to the text component can then be rejected, accepted or
transformed in these two methods.
Let us start with an editable combo box that is not accepting anything to demonstrate how to
change the editor component's document.
*/
import javax.swing.*;
import javax.swing.text.*;
public class S01BadDocument extends PlainDocument {
public void insertString(int offs, String str, AttributeSet a) {
// reject the insert but print a message on the console
System.out.println("insert " + str + " at " + offs);
}
private static void createAndShowGUI() {
// the combo box (add/modify items if you like to)
JComboBox comboBox = new JComboBox(new Object[] {"Ester", "Jordi", "Jordina", "Jorge", "Sergi"});
// has to be editable
comboBox.setEditable(true);
// get the combo boxes editor component
JTextComponent editor = (JTextComponent) comboBox.getEditor().getEditorComponent();
// change the editor's document
editor.setDocument(new S01BadDocument());
// create and show a window containing the combo box
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(3);
frame.getContentPane().add(comboBox);
frame.pack(); frame.setVisible(true);
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
