Reading Specific Text from a JTextField

Question

Hello I am currently trying to create a computer game\program and the main thing that it uses is input from the user, commands, in a JTextField. So I already have a basic text field set up called "question" (JTextField question = new JTextField(15);) in a JFrame and an OK button to enter the text. Next is a String "answer". This is: String answer = question.getText().toUpperCase();

This is how the field is set up. Net is the 3 if statements that give an error if no text is entered, if it is not the right word, and of course, the correct answer. They are as follows:

Public class ButtonListener extends ActionListener
{
     publix void actionPerformed(ActionEvent e)
     {
          if(e.getSource() == buttonOK)
          {
           String answer = question.getText().toUpperCase();

          if(answer.length() == 0)
          {
               JOptionPane.showMessageDialog(
                    Window.this,
                    "ERROR: NO INPUT",
                    "ERROR",
                    JOptionPane.INFORMATION_MESSAGE);
          }

          if(answer == "XENIX")
          {
               JOptionPane.showMessageDialog(
                    Window.this,
                    "Welcome, Sir",
                    "Greetings",
                    JOptionPane.INFORMATION_MESSAGE);
          }

          if(answer != "XENIX" && answer.length > 0)
          {
               JOptionPane.showMessageDialog(
                    Window.this,
                    "ERROR: INCORECT PASSWORD",
                    "ERROR",
                    JOptionPane.INFORMATION_MESSAGE);
          }

This is how the if statements react when text is entered and the ok button is pressed. Everything works but when I type in "Xenix", it says "ERROR: INCORRECT PASSWORD". The, "Welcome, Sir" message never shows, even though using a print method it shows it is clearly getting "XENIX" from the answer. Why is it not working? Is there another method I'm supposed to use? Please respond soon! Thanks!

Sorry about the weird layout. Not sure why it posted so funky. If you have a question about Syntax, please ask! — Nicholas Creech, Sep 24 '13 at 23:18
Layout corrected. Please do read the help information when editing your posts which will explain how to make sure that your code formatting is shown. And as @Reimeus states, do not use `==` to compare Strings as this only compares if the objects are one and the same, which is not what you're interested. — Hovercraft Full Of Eels, Sep 24 '13 at 23:20
Okay thanks it worked! But what about when I need to compare is they DON'T equal eachother because now != doesn't work. — Nicholas Creech, Sep 24 '13 at 23:27
@NicholasCreech do `!equals(...)` instead, then. The `!` character inverts the logic, so it basically says `NOTequals(...)`* (*not actual syntax). — Birb, Sep 24 '13 at 23:30
@HovercraftFullOfEels: opposite of .equals???? != doesnt work. — Nicholas Creech, Sep 24 '13 at 23:31
That was not my comment but rather @Izmaki, and he is giving you bad advice. You would do `if (!someString.equals(otherString)) {`. this is no different from using `!` with any other boolean expression. Avoid thinking in a concrete fashion, but rather use general concepts in new ways in order to move ahead. — Hovercraft Full Of Eels, Sep 24 '13 at 23:33
@Izmaki it underlines it saying, "Incompatible operand types String and boolean" — Nicholas Creech, Sep 24 '13 at 23:33
@HovercraftFullOfEels: I see how my comment is slightly confusing - my bad. It should of course have said `!answer.equals("XENIX")`. — Birb, Sep 24 '13 at 23:36
@HoverCraftFullOfEels: Thanks so much! I hate it when a problem has such an easy fix. Thanks everyone else too! :D — Nicholas Creech, Sep 24 '13 at 23:36

score 3 · Accepted Answer · edited Sep 25 '13 at 05:55

3

if(question.getText() !=null && !question.getText().isEmpty())
{
    String answer = question.getText().toUpperCase();

    if(answer.length() == 0)
    {
        ------------------
        ------------------
    }   

    if(answer.equals("XENIX"))
    {
        ------------------
        ------------------
    }

    if((!answer.equals("XENIX")) && answer.length > 0)
    {
        ------------------
        ------------------
    }
}

edited Sep 25 '13 at 05:55

Anatoliy Nikolaev

22,370
15
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answered Sep 24 '13 at 23:27

Prabhakaran Ramaswamy

25,706
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64

1

You should never compare String's with ==. Use the `equals(...)` method, instead. Edit: cheers. ;) – Birb Sep 24 '13 at 23:28
1

Thnx @lzmaki updated the answer – Prabhakaran Ramaswamy Sep 24 '13 at 23:31

Reading Specific Text from a JTextField

1 Answers1