Menu
How to limit the number of characters entered in a JTextField?
Suppose I want to enter say 5 characters max. After that no characters can be entered into it.
801
addKeyListener(new KeyAdapter() { public void keyTyped(KeyEvent e) { if (txtGuess. getText(). length() >= 3 ) // limit textfield to 3 characters e.
txtAnswer. addKeyListener(new KeyAdapter() { @Override public void keyPressed(KeyEvent e) { int key = e. getKeyCode(); /* Restrict input to only integers */ if (key < 96 && key > 105) e. setKeyChar(''); }; });
put your jtextfield within a JPanel, now that JPanel is the one which will have large size, but that won't be visible and then you can control the layout of JPanel and hence you can control the size of the jtextfield.
Only one line of user response will be accepted. If multiple lines are desired, JTextArea will be needed. As with all action events, when an event listener registers an event, the event is processed and the data in the text field can be utilized in the program.
http://www.rgagnon.com/javadetails/java-0198.html
import javax.swing.text.PlainDocument; import javax.swing.text.AttributeSet; import javax.swing.text.BadLocationException; public class JTextFieldLimit extends PlainDocument { private int limit; JTextFieldLimit(int limit) { super(); this.limit = limit; } public void insertString( int offset, String str, AttributeSet attr ) throws BadLocationException { if (str == null) return; if ((getLength() + str.length()) <= limit) { super.insertString(offset, str, attr); } } } Then
import java.awt.*; import javax.swing.*; public class DemoJTextFieldWithLimit extends JApplet{ JTextField textfield1; JLabel label1; public void init() { getContentPane().setLayout(new FlowLayout()); // label1 = new JLabel("max 10 chars"); textfield1 = new JTextField(15); getContentPane().add(label1); getContentPane().add(textfield1); textfield1.setDocument (new JTextFieldLimit(10)); } } (first result from google)
56
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
