Get text from JTextField and convert to a double

Question

How do I write code to get text from JTextField and convert to a double?

I have created a bank account class and a bank account GUI with amountField to show the amount i wish to withdraw and deposit. Using public void actionPerformed(ActionEvent e) method how can I write code to get text from amountField and convert to a double?

I want to input account details and be able to withdraw and deposit whilst storing values within a string

write event handler for deposit button
write event handler for withdraw button

public class BankAccountGUI extends JFrame implements ActionListener
{
    private Label amountLabel = new Label("Amount");
    private JTextField amountField = new JTextField(5);
    private JButton depositButton = new JButton("DEPOSIT");
    private JButton withdrawButton = new JButton("WITHDRAW");
    private Label balanceLabel = new Label("Starting Balance = 0" );

    private JPanel topPanel = new JPanel();
    private JPanel bottomPanel = new JPanel();
    private JPanel middlePanel = new JPanel();


    BankAccount myAccount = new BankAccount("James","12345");

    // declare a new BankAccount object (myAccount) with account number and name of your choice here


    public BankAccountGUI()
    {
        setTitle("BankAccount GUI");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        setSize(340, 145);
        setLocation(300,300);
        depositButton.addActionListener(this);
        withdrawButton.addActionListener(this);

        topPanel.add(amountLabel);
        topPanel.add(amountField);
        bottomPanel.add(balanceLabel);
        middlePanel.add(depositButton);
        middlePanel.add(withdrawButton);


        add (BorderLayout.NORTH, topPanel);
        add(BorderLayout.SOUTH, bottomPanel);
        add(BorderLayout.CENTER, middlePanel);

        setVisible(true);
    }


    public void actionPerformed(ActionEvent e)
    {
         //What goes here?
    }
}

Its best to share your own research on what you tried and what didn't work. — Nikhil Sahu, Jul 16 '19 at 20:39
I dont actually have a clue of how to get text from the amount field — NostackJay, Jul 16 '19 at 20:46
Possible duplicate of [How to Retrieve value from JTextField in Java Swing?](https://stackoverflow.com/questions/5752307/how-to-retrieve-value-from-jtextfield-in-java-swing) — Nikhil Sahu, Jul 16 '19 at 21:01
For future reference, try to keep questions to one per post. You're asking two questions here: How to get the value out of a JTextField, and How to convert a String to a Double. It's also highly encouraged to try searching for your question prior to posting. Especially with Java, the odds of finding something useful here are very high. Happy Coding! — Stephan, Jul 16 '19 at 21:05

score 1 · Answer 1 · answered Jul 16 '19 at 20:52

1

You are probably going to want to try using Double.parseDouble(string). for example:

String str = "12.0";
Double e = Double.parseDouble(str);
        System.out.println(e * 1.5); //returns 18

answered Jul 16 '19 at 20:52

Dylan Graham

21
2

https://www.journaldev.com/18392/java-convert-string-to-double you can see more examples here – Dylan Graham Jul 16 '19 at 20:52
This answers the question only partially and even the important bit. Moreover, answers to non-reasearched questions are highly discouraged. https://stackoverflow.com/help/how-to-ask – Nikhil Sahu Jul 16 '19 at 21:00

score 0 · Answer 2 · edited Jun 20 '20 at 09:12

0

There's a number of things here you need to do differently. In a nutshell, you're looking for 'JTextField.getText()', and 'Double.parseDouble()'

depositButton.addActionListener(new ActionListener() {
    @Override
    public void actionPerformed(ActionEvent e) {
        //Get the Text Value out of the UI Component
        String rawAmount=amountField.getText();

        //Convert that value to Double
        try{
            Double convertedValue = Double.parseDouble(rawAmount);
            //Do stuff with the convertedValue
        }catch(Exception e){
            System.out.println("Not A Double Value");
        }
    }
});

You should also use separate listeners for each button to save you the trouble of trying to programmatically determine which button generated the event.

See the documentation for JTextField

edited Jun 20 '20 at 09:12

Community

1
1

answered Jul 16 '19 at 21:00

Stephan

666
8
23

Thanks for the reply. But can you explain how this would store the input to a string. It’s all confusing for me to understand at the moment – NostackJay Jul 16 '19 at 22:47
If you look at the line where I call getText() : that's called an assignment operation. GetText is returning the string out of the field, which is then stored in the variable declared to the left of the = – Stephan Jul 16 '19 at 22:49

Get text from JTextField and convert to a double

2 Answers2