Java examples for Swing:Text Input Verifier
Warn user when their input is bad with dialog and InputVerifier
/*/* w ww. j a v a 2 s . c o m*/ * InputVerificationDialogDemo.java requires no other files. */ import java.util.Set; import java.util.HashSet; import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.event.*; import javax.swing.text.*; import java.beans.PropertyChangeListener; import java.beans.PropertyChangeEvent; import java.text.*; /** * InputVerificationDialogDemo.java is a 1.4 example that * requires no other files. * * Yet another mortgage calculator. * However, instead of using a formatted text field, * as shown in FormattedTextFieldDemo, this example * uses input verification to validate user input. * This one uses a dialog to warn people when their input is bad. */ public class InputVerificationDialogDemo extends JPanel { //Default values private static double DEFAULT_AMOUNT = 100000; private static double DEFAULT_RATE = 7.5; //7.5 % private static int DEFAULT_PERIOD = 30; //Labels to identify the text fields private JLabel amountLabel; private JLabel rateLabel; private JLabel numPeriodsLabel; private JLabel paymentLabel; //Strings for the labels private static String amountString = "Loan Amount (10,000 - 10,000,000): "; private static String rateString = "APR (>= 0%): "; private static String numPeriodsString = "Years (1-40): "; private static String paymentString = "Monthly Payment: "; //Text fields for data entry private JTextField amountField; private JTextField rateField; private JTextField numPeriodsField; private JTextField paymentField; //Formats to format and parse numbers private NumberFormat moneyFormat; private NumberFormat percentFormat; private DecimalFormat decimalFormat; private DecimalFormat paymentFormat; private NumberFormat integerFormat; private MyVerifier verifier = new MyVerifier(); public InputVerificationDialogDemo() { super(new BorderLayout()); setUpFormats(); double payment = computePayment(DEFAULT_AMOUNT, DEFAULT_RATE, DEFAULT_PERIOD); //Create the labels. amountLabel = new JLabel(amountString); rateLabel = new JLabel(rateString); numPeriodsLabel = new JLabel(numPeriodsString); paymentLabel = new JLabel(paymentString); //Create the text fields and set them up. amountField = new JTextField(moneyFormat.format(DEFAULT_AMOUNT), 10); amountField.setInputVerifier(verifier); rateField = new JTextField(percentFormat.format(DEFAULT_RATE), 10); rateField.setInputVerifier(verifier); numPeriodsField = new JTextField( decimalFormat.format(DEFAULT_PERIOD), 10); numPeriodsField.setInputVerifier(verifier); paymentField = new JTextField(paymentFormat.format(payment), 10); paymentField.setInputVerifier(verifier); paymentField.setEditable(false); //Remove this component from the focus cycle. paymentField.setFocusable(false); paymentField.setForeground(Color.red); //Register an action listener to handle Return. amountField.addActionListener(verifier); rateField.addActionListener(verifier); numPeriodsField.addActionListener(verifier); //Tell accessibility tools about label/textfield pairs. amountLabel.setLabelFor(amountField); rateLabel.setLabelFor(rateField); numPeriodsLabel.setLabelFor(numPeriodsField); paymentLabel.setLabelFor(paymentField); //Lay out the labels in a panel. JPanel labelPane = new JPanel(new GridLayout(0, 1)); labelPane.add(amountLabel); labelPane.add(rateLabel); labelPane.add(numPeriodsLabel); labelPane.add(paymentLabel); //Layout the text fields in a panel. JPanel fieldPane = new JPanel(new GridLayout(0, 1)); fieldPane.add(amountField); fieldPane.add(rateField); fieldPane.add(numPeriodsField); fieldPane.add(paymentField); //Put the panels in this panel, labels on left, //text fields on right. setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20)); add(labelPane, BorderLayout.CENTER); add(fieldPane, BorderLayout.LINE_END); } class MyVerifier extends InputVerifier implements ActionListener { double MIN_AMOUNT = 10000.0; double MAX_AMOUNT = 10000000.0; double MIN_RATE = 0.0; int MIN_PERIOD = 1; int MAX_PERIOD = 40; String message = null; public boolean shouldYieldFocus(JComponent input) { boolean inputOK = verify(input); makeItPretty(input); updatePayment(); if (inputOK) { return true; } //Pop up the message dialog. message += ".\nPlease try again."; JOptionPane.showMessageDialog(null, //no owner frame message, //text to display "Invalid Value", //title JOptionPane.WARNING_MESSAGE); //Reinstall the input verifier. input.setInputVerifier(this); //Beep and then tell whoever called us that we don't //want to yield focus. Toolkit.getDefaultToolkit().beep(); return false; } protected void updatePayment() { double amount = DEFAULT_AMOUNT; double rate = DEFAULT_RATE; int numPeriods = DEFAULT_PERIOD; double payment = 0.0; //Parse the values. try { amount = moneyFormat.parse(amountField.getText()) .doubleValue(); } catch (ParseException pe) { } try { rate = percentFormat.parse(rateField.getText()) .doubleValue(); } catch (ParseException pe) { } try { numPeriods = decimalFormat.parse(numPeriodsField.getText()) .intValue(); } catch (ParseException pe) { } //Calculate the result and update the GUI. payment = computePayment(amount, rate, numPeriods); paymentField.setText(paymentFormat.format(payment)); } //This method checks input, but should cause no side effects. public boolean verify(JComponent input) { return checkField(input, false); } protected void makeItPretty(JComponent input) { checkField(input, true); } protected boolean checkField(JComponent input, boolean changeIt) { if (input == amountField) { return checkAmountField(changeIt); } else if (input == rateField) { return checkRateField(changeIt); } else if (input == numPeriodsField) { return checkNumPeriodsField(changeIt); } else { return true; //shouldn't happen } } //Checks that the amount field is valid. If it is valid, //it returns true, otherwise it sets the message field and //returns false. If the change argument is true, set //the textfield to the parsed number so that it looks //good -- no letters, for example. public boolean checkAmountField(boolean change) { boolean wasValid = true; double amount = DEFAULT_AMOUNT; //Parse the value. try { amount = moneyFormat.parse(amountField.getText()) .doubleValue(); } catch (ParseException pe) { message = "Invalid money format in Loan Amount field"; return false; } //Value was invalid. if ((amount < MIN_AMOUNT) || (amount > MAX_AMOUNT)) { wasValid = false; if (amount < MIN_AMOUNT) { message = "Loan Amount was < " + integerFormat.format(MIN_AMOUNT); } else { //amount is greater than MAX_AMOUNT message = "Loan Amount was > " + integerFormat.format(MAX_AMOUNT); } } //Whether value was valid or not, format it nicely. if (change) { amountField.setText(moneyFormat.format(amount)); amountField.selectAll(); } return wasValid; } //Checks that the rate field is valid. If it is valid, //it returns true, otherwise it sets the message field and //returns false. If the change argument is true, set the //textfield to the parsed number so that it looks good -- no //letters, for example. public boolean checkRateField(boolean change) { boolean wasValid = true; double rate = DEFAULT_RATE; //Parse the value. try { rate = percentFormat.parse(rateField.getText()) .doubleValue(); } catch (ParseException pe) { message = "Invalid percent format in APR field"; return false; } //Value was invalid. if (rate < MIN_RATE) { wasValid = false; message = "Bad value: APR was < " + MIN_RATE; } //Whether value was valid or not, format it nicely. if (change) { rateField.setText(percentFormat.format(rate)); rateField.selectAll(); } return wasValid; } //Checks that the numPeriods field is valid. If it is valid, //it returns true, otherwise it sets the message field and //returns false. If the change argument is true, set the //textfield to the parsed number so that it looks good -- no //letters, for example. public boolean checkNumPeriodsField(boolean change) { boolean wasValid = true; int numPeriods = DEFAULT_PERIOD; //Parse the value. try { numPeriods = decimalFormat.parse(numPeriodsField.getText()) .intValue(); } catch (ParseException pe) { message = "Invalid decimal format in Years field"; return false; } //Value was invalid. if (numPeriods < MIN_PERIOD) { wasValid = false; message = "Bad value: Number of years was < " + integerFormat.format(MIN_PERIOD); } else if (numPeriods > MAX_PERIOD) { wasValid = false; message = "Bad value: Number of years was > " + integerFormat.format(MAX_PERIOD); } //Whether value was valid or not, format it nicely. if (change) { numPeriodsField.setText(decimalFormat.format(numPeriods)); numPeriodsField.selectAll(); } return wasValid; } public void actionPerformed(ActionEvent e) { JTextField source = (JTextField) e.getSource(); shouldYieldFocus(source); //ignore return value source.selectAll(); } } /** * Create the GUI and show it. For thread safety, * this method should be invoked from the * event-dispatching thread. */ private static void createAndShowGUI() { //Create and set up the window. JFrame frame = new JFrame("InputVerificationDialogDemo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JComponent newContentPane = new InputVerificationDialogDemo(); newContentPane.setOpaque(true); //content panes must be opaque frame.setContentPane(newContentPane); //Display the window. frame.pack(); frame.setVisible(true); } public static void main(String[] args) { /* Use an appropriate Look and Feel */ try { //UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); //UIManager.setLookAndFeel("com.sun.java.swing.plaf.gtk.GTKLookAndFeel"); UIManager .setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel"); } catch (UnsupportedLookAndFeelException ex) { ex.printStackTrace(); } catch (IllegalAccessException ex) { ex.printStackTrace(); } catch (InstantiationException ex) { ex.printStackTrace(); } catch (ClassNotFoundException ex) { ex.printStackTrace(); } /* Turn off metal's use of bold fonts */ UIManager.put("swing.boldMetal", Boolean.FALSE); //Schedule a job for the event-dispatching thread: //creating and showing this application's GUI. javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGUI(); } }); } //Compute the monthly payment based on the loan amount, //APR, and length of loan. double computePayment(double loanAmt, double rate, int numPeriods) { double I, partial1, denominator, answer; numPeriods *= 12; //get number of months if (rate > 0.01) { I = rate / 100.0 / 12.0; //get monthly rate from annual partial1 = Math.pow((1 + I), (0.0 - numPeriods)); denominator = (1 - partial1) / I; } else { //rate ~= 0 denominator = numPeriods; } answer = (-1 * loanAmt) / denominator; return answer; } //Create and set up number formats. These objects also //parse numbers input by user. private void setUpFormats() { moneyFormat = (NumberFormat) NumberFormat.getNumberInstance(); percentFormat = NumberFormat.getNumberInstance(); percentFormat.setMinimumFractionDigits(3); decimalFormat = (DecimalFormat) NumberFormat.getNumberInstance(); decimalFormat.setParseIntegerOnly(true); paymentFormat = (DecimalFormat) NumberFormat.getNumberInstance(); paymentFormat.setMaximumFractionDigits(2); paymentFormat.setNegativePrefix("("); paymentFormat.setNegativeSuffix(")"); integerFormat = NumberFormat.getIntegerInstance(); } } /* * Copyright (c) 1995, 2008, Oracle and/or its affiliates. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * - Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * - Neither the name of Oracle or the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */