Reputation: 97
I am building a simple JFrame GUI requiring user input. If the user clicks the submit button, it checks for input then either renders a JOptionPane message telling the user to completely fill out the form, or it tells the user that the form submitted and closes the program. The problme is that if the user left blank fields, the message dialog box renders and only adds to the loop count if you try to close it and does not allow the user to return to the JFrame to apply input to the form.
import java.io.*;
import java.util.*;
import javax.swing.*;
import javax.swing.JOptionPane;
import java.awt.*;
import java.util.Scanner.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
/**
*
* @author joel.ramsey
*/
public class JRStarPhase5 extends JFrame{
public static void main (String [] args) throws IOException {
JFrame window = new JRStarPhase5();
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setVisible(true);
}//end main method
private boolean validationError;
private final JTextField fNameInput;
private final JTextField miInput;
private final JTextField lNameInput;
private final JTextField productChoiceInput;
private final JTextField licenseQuantityInput;
private final JTextField streetAddressInput;
private final JTextField cityInput;
private final JTextField stateInput;
private final JTextField zipInput;
private final JTextField phoneInput;
//constructor for JFrame
public JRStarPhase5(){
setTitle("JRStar Star Gaze Order Processing");
setSize (800,800);
Container pane = getContentPane();
GridLayout grid = new GridLayout(0,2);
pane.setLayout(grid);
JLabel fNameLabel = new JLabel ("First name:");
JLabel mi = new JLabel ("Middle initial:");
JLabel lNameLabel = new JLabel ("Last name:");
JLabel productChoice = new JLabel ("Star Gaze version:");
JLabel licenseQuantity = new JLabel ("License quantity:");
JLabel streetAddress = new JLabel ("Street address:");
JLabel city = new JLabel ("City:");
JLabel state = new JLabel ("State abbrev:");
JLabel zip = new JLabel ("Zip code:");
JLabel phone = new JLabel ("Phone Number:");
this.fNameInput = new JTextField(15);
this.miInput = new JTextField (1);
this.lNameInput = new JTextField (15);
this.productChoiceInput = new JTextField (1);
this.licenseQuantityInput = new JTextField (2);
this.streetAddressInput = new JTextField (20);
this.cityInput = new JTextField (20);
this.stateInput = new JTextField (2);
this.zipInput = new JTextField (5);
this.phoneInput = new JTextField (10);
//add as last buttons
JButton submit = new JButton("Submit");
SubmitButtonHandler sbh = new SubmitButtonHandler();
submit.addActionListener(sbh);
JButton clear = new JButton("Clear");
ClearButtonHandler cbh = new ClearButtonHandler();
clear.addActionListener(cbh);
pane.add(fNameLabel);
pane.add(fNameInput);
pane.add(mi);
pane.add(miInput);
pane.add(lNameLabel);
pane.add(lNameInput);
pane.add(productChoice);
pane.add(productChoiceInput);
pane.add(licenseQuantity);
pane.add(licenseQuantityInput);
pane.add(streetAddress);
pane.add(streetAddressInput);
pane.add(city);
pane.add(cityInput);
pane.add(state);
pane.add(stateInput);
pane.add(zip);
pane.add(zipInput);
pane.add(phone);
pane.add(phoneInput);
//add last
pane.add(submit);
pane.add(clear);
}//end constructor
private class SubmitButtonHandler implements ActionListener{
public void actionPerformed(ActionEvent e){
validationError = (fNameInput.getText().equals("")||
miInput.getText().equals("")||
lNameInput.getText().equals("")||
streetAddressInput.getText().equals("")||
cityInput.getText().equals("")||
stateInput.getText().equals("")||
zipInput.getText().equals("")||
phoneInput.getText().equals(""));
for (int n=1; n<3; n++){
if (validationError){
if (n == 3){
System.exit(0);
}
JOptionPane.showMessageDialog(null,"Please complete each field within the order form.");
}
else break;
}
if (validationError = false)
JOptionPane.showMessageDialog(null,"Your order has been submitted!");
System.exit(0);
}
}//end submit
private class ClearButtonHandler implements ActionListener{
public void actionPerformed(ActionEvent e){
fNameInput.setText("");
miInput.setText("");
lNameInput.setText("");
productChoiceInput.setText("");
licenseQuantityInput.setText("");
streetAddressInput.setText("");
cityInput.setText("");
stateInput.setText("");
zipInput.setText("");
phoneInput.setText("");
}
}//end clear
}//end main class
Upvotes: 0
Views: 2294
Reputation: 347332
I honestly don't know what else you expected (no offense).
Swing is a event driven environment. An event occurs, you react to it...
The loop will execute within the context of the EDT to start with, meaning that there is no way a user could actually close the dialog, correct the error and try to re-submit.
Even if it did, the loop does not allow for any opportunity for the validationError
variable to be re-evaluated, meaning it will always be what it was originally set to earlier in the method (lets assume true
for now)...
for (int n = 1; n < 3; n++) {
if (validationError) {
if (n == 3) {
System.exit(0);
}
JOptionPane.showMessageDialog(null, "Please complete each field within the order form.");
} else {
break;
}
}
if (validationError = false) {
JOptionPane.showMessageDialog(null, "Your order has been submitted!");
}
System.exit(0);
So basically you have a death trap, there is simply no way to escape...
Let's take another approach. Rather than using a hard-loop, like for
or while
, we can create a soft loop, whereby, each time the method is executed and the form is invalid, we update a counter, until that counter runs out...
// How many times retries has the user used...
private int retries = 0;
/*...*/
public void actionPerformed(ActionEvent e) {
validationError = (fNameInput.getText().equals("")
|| miInput.getText().equals("")
|| lNameInput.getText().equals("")
|| streetAddressInput.getText().equals("")
|| cityInput.getText().equals("")
|| stateInput.getText().equals("")
|| zipInput.getText().equals("")
|| phoneInput.getText().equals(""));
if (validationError) {
retries++;
if (retries < 3) {
JOptionPane.showMessageDialog(this, "Please complete each field within the order form.");
} else {
JOptionPane.showMessageDialog(this, "You've used up all your tries...");
System.exit(0);
}
} else {
JOptionPane.showMessageDialog(this, "Your order has been submitted!");
System.exit(0);
}
}
You may also like to have a read of Validating Input from the How to use the focus subsystem tutorial...
Upvotes: 1