I am trying to create a GUI that allows someone to set up an account. I would like to validate that all the text fields are complete when the create account button is pressed. What is the best way to do this? I am attaching my code but my validation that the text fields are complete is not working.
see code below:
public class GUIaccounts extends JFrame{
private JLabel name;
private JLabel initDeposit;
private JLabel chooseAccount;
private JLabel empty;
private JTextField nameTextField;
private JTextField initDepositTextField;
private JPanel dataPanel;
private JPanel accountTypePanel;
private JRadioButton savingsAccount;
private JRadioButton premiereChecking;
private ButtonGroup radioButtonGroup;
private JButton createAccountButton;
private JPanel createAccountPanel;
private Bank myBank;
public GUIaccounts(){
setTitle("Create an Account");
setSize(1000,1000);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
buildPanels();
setVisible(true);
pack();
setLocationRelativeTo(null);
myBank=new Bank();
}
private void buildPanels(){
//create the panels
dataPanel= new JPanel();
dataPanel.setLayout(new GridLayout(2,2));
accountTypePanel=new JPanel();
accountTypePanel.setLayout(new GridLayout(3,1));
createAccountPanel=new JPanel();
createAccountPanel.setLayout(new FlowLayout());
//create labels
name=new JLabel("Enter Name:");
Border border = LineBorder.createBlackLineBorder();
name.setBorder(border);
initDeposit=new JLabel("Enter Initial Deposit:");
initDeposit.setBorder(border);
chooseAccount=new JLabel("Choose Account:");
empty=new JLabel(" ");
//create text fields
nameTextField=new JTextField();
initDepositTextField=new JTextField();
//create buttons
savingsAccount = new JRadioButton("Savings Account");
premiereChecking =new JRadioButton ("Premiere Checking Account");
createAccountButton=new JButton("Create Account");
//add labels and field to the panel
dataPanel.add(name);
dataPanel.add(nameTextField);
dataPanel.add(initDeposit);
dataPanel.add(initDepositTextField);
//add button to the panel
accountTypePanel.add(chooseAccount);
accountTypePanel.add(empty);
accountTypePanel.add(savingsAccount);
accountTypePanel.add(premiereChecking);
createAccountPanel.add(createAccountButton);
//add actionListeners to the buttons
savingsAccount.addActionListener(new RadioButtonListener());
premiereChecking.addActionListener(new RadioButtonListener());
createAccountButton.addActionListener(new createAccountListener());
//add focus to the text field
nameTextField.addFocusListener(new nameFieldListener());
initDepositTextField.addFocusListener(new initDepositFieldListener());
//add panels to the contentPane
add(dataPanel, BorderLayout.NORTH);
add(accountTypePanel, BorderLayout.CENTER);
add(createAccountPanel, BorderLayout.SOUTH);
//group radio buttons
radioButtonGroup= new ButtonGroup();
radioButtonGroup.add(savingsAccount);
radioButtonGroup.add(premiereChecking);
}
private class createAccountListener implements ActionListener{
public void actionPerformed(ActionEvent e){
String name=null;
Double amount=null;
if (savingsAccount.isSelected()){
name=nameTextField.getText();
amount=Double.valueOf(initDepositTextField.getText());
if(name!=null && amount !=null){
try{
SavingsAccount account=new SavingsAccount(name,AccountIDs.getNextID(), amount);
myBank.addAccount(account);
JOptionPane.showMessageDialog(null,"Account setup was successful" + myBank.toString());
}
catch(Exception e1){
JOptionPane.showMessageDialog(null,"Unable to set up account. " +e1.getMessage());
}
}
else{
JOptionPane.showMessageDialog(null, "All fields must be completed in order to set up account");
}
}
else if(premiereChecking.isSelected()){
name=nameTextField.getText();
amount=Double.valueOf(initDepositTextField.getText());
if(name!=null && amount!=null){
try{
PremiereCheckingAccount account=new PremiereCheckingAccount(name, AccountIDs.getNextID(),amount);
myBank.addAccount(account);
JOptionPane.showMessageDialog(null,"Account setup was successful" +myBank.toString());
}
catch(Exception e1){
JOptionPane.showMessageDialog(null,"Unable to set up account. " + e1.getMessage());
}
}
else{
JOptionPane.showMessageDialog(null, "All fields must be completed in order to set up account");
}
}
else{
JOptionPane.showMessageDialog(null,"Please select the type of account you want to create.");
}
}
}
private class RadioButtonListener implements ActionListener{
public void actionPerformed(ActionEvent e){
}
}
private class nameFieldListener implements FocusListener{
public void focusGained(FocusEvent e){
nameTextField.selectAll();//highlight contents
}
public void focusLost(FocusEvent e){
}
}
private class initDepositFieldListener implements FocusListener{
public void focusGained(FocusEvent e){
initDepositTextField.selectAll();
}
public void focusLost(FocusEvent e) {
}
}
public static void main(String[]args){
GUIaccounts myAccount=new GUIaccounts();
}
}
The getText() method will not return null. It will return the empty String ("").
Your test should be something like:
if ( textField.getText().trim().length() == 0 )
// error
Old question, but it's generally a good idea to create a "validation" helper method that does all the validation first, then if it checks out you can load all the values into whatever you're doing (variables, class attributes to instantiate something, etc).
eg:
private class createAccountListener implements ActionListener
{
public void actionPerformed(ActionEvent ae)
{
// first we validate all fields... if they pass, we do
// the rest of the code, otherwise we let the failed validation
// code tell user what happened, and skip the rest of the code
if ( validateFields() )
{
String fname = fieldFirstName.getText();
String lname = fieldFirstName.getText();
int age = fieldAge.getText();
}
}
}
// test all text fields for input
public boolean validateFields()
{
if (! validateField( fieldFirstName, "Please enter a first name")
return false;
else
if (! validateField( fieldLastName, "Please enter a last name")
return false;
else
if (! validateInteger( fieldAge, "Please enter an age greater then 0")
return false;
else
return true;
}
// test if field is empty
public boolean validateField( JTextField f, String errormsg )
{
if ( f.getText().equals("") )
return failedMessage( f, errormsg );
else
return true; // validation successful
}
public boolean validateInteger( JTextField f, String errormsg )
{
try
{ // try to convert input to integer
int i = Integer.parseInt(f.getText());
// input must be greater then 0
// if it is, success
if ( i > 0 )
return true; // success, validation succeeded
}
catch(Exception e)
{
// if conversion failed, or input was <= 0,
// fall-through and do final return below
}
return failedMessage( f, errormsg );
}
public boolean failedMessage(JTextField f, String errormsg)
{
JOptionPane.showMessageDialog(null, errormsg); // give user feedback
f.requestFocus(); // set focus on field, so user can change
return false; // return false, as validation has failed
}
来源：https://stackoverflow.com/questions/6400431/java-validating-that-all-text-fields-in-gui-are-completed