[RESOLVED] Java question

Hi, is there any website have a lots of sample code and eg. to download. I'm quite new to JAVA cos no sticky threads for this.

& also how can I do a simple buttongroup with captions?

TIA :)

Quote:

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Originally Posted by abcat

Hi, is there any website have a lots of sample code and eg. to download. I'm quite new to JAVA cos no sticky threads for this.

& also how can I do a simple buttongroup with captions?

TIA :)

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This is Java not VB6 (i.e. Object oriented) You can create an Array of JButton objects and give each a text (using setText method), maybe use a loop for that

Hi, Thanks for replying :) So u mean no place eg. Tutorials to download and learn Java easily with some samples. I remember I go Java website and download all the 4 packs which are quite normal.. I wonder is there a better 1?

Anyway for buttongroup caption I think I use TitledBorder.

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I remember I go Java website and download all the 4 packs which are quite normal.. I wonder is there a better 1?

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What 4 packs are you talking about??
There are no packs in java. there are 3 main technologies (JSE, JEE, JME)
if you want some tutorials, you can visit the java.sun.com. They have some useful tutorials and how to start articles there

I think I d.l this 4 http://java.sun.com/docs/books/tutor.../download.html . Haven't really read it. I wonder is there more sample coding with comments to download?

Quote:

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Originally Posted by ComputerJy

if you want some tutorials, you can visit the java.sun.com. They have some useful tutorials and how to start articles there

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May be this is the best place in Java world.:blush:

Check more on about.com site.

Well, I rarely look at other people's code unless they need help
But I've visited Planet source code and I think it's a good place.

P.S. Read the articles in the main page they are actually useful most of the time

Thanks for all the website :) I think its gonna be a good reference for me :o Btw, I encountered 1 simple problem while coding my programs.

Its about JTextField, by default for my program, the JTextField had a default text to call user to input text. How can I validate that the JTextField had been altered with a new string and then prompt for an error message if the text remain the same? I try using boolean expression like if txtField.getText() == txtField.getText() and also txtField.getText() == "default text I have put" but it doesn't seems to work.

Is JTextField cannot use ActionListener for events?

I wanna make it like when user once click over the JTextField, the default text will be gone and then user can start to type and my program will validate it if its blank string then error msg prompted..

Thanks :)

I think the FocusListener should do it for you:

Code:

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        txtField.addFocusListener(new FocusListener(){

            @Override
            public void focusGained(FocusEvent e) {
               
            }

            @Override
            public void focusLost(FocusEvent e) {
               
            }
           
        });

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To compare strings use:

Code:

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String str="This is a string";
if(str.equals("This is a string"));

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Hi ComputerJY, thanks again for your help :) The equal works well as previously I using == and it doesn't seems to work, don't know why.

Regarding the FocusListener, how can I use it? I think I use it the wrong way resulting in program startup, textfield straight away change instead of mouse over and click it.

Code:

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public class TextField implements FocusListener
    {
        public void focusGained(FocusEvent e) {
          if (e.getSource() == txtField) {
                txtField.setText("");
              }
 
             
              public void focusLost(FocusEvent e) {
                //Try on putting here also wrong, don't really know how it works though :(
             
                          }

              }

    }

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The equal works well as previously I using == and it doesn't seems to work, don't know why.

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The "==" compares Object references (something like a pointers) and they'll be equal only if it was the exact same object.

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Regarding the FocusListener, how can I use it? I think I use it the wrong way resulting in program startup, textfield straight away change instead of mouse over and click it.

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It might be that the form has nothing but the JTextField or maybe it's the number 0 in the tab index map so it gains focus on startup

Thanks for the explanation but somehow I'm still not understand on the FocusListener. I can't seems to make it work like those ActionListener. Actually I just want to make it like those website with forms with textbox with default text, and user click the textbox, the default text will be gone? Any idea?

Check this out and tell me if it's what you are looking for:

Code:

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import java.awt.BorderLayout;
import java.awt.HeadlessException;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import javax.swing.JFrame;
import javax.swing.JTextField;

public class TestFrame extends JFrame {

    private static final long serialVersionUID = -7356866315584500438L;

    /**
    * @throws HeadlessException
    */
    public TestFrame() throws HeadlessException {
        super("Test Project");

        JTextField normalTextField = new JTextField();
        normalTextField.setText("This text is here to stay");
        this.add(normalTextField,BorderLayout.NORTH);
       
        final JTextField textLostOnFocus = new JTextField();
        textLostOnFocus.setText("This text will be lost on focus");
       
        textLostOnFocus.addFocusListener(new FocusListener(){

            @Override
            public void focusGained(FocusEvent e) {
                textLostOnFocus.setText("");
            }

            @Override
            public void focusLost(FocusEvent e) {
            }
        });
        this.add(textLostOnFocus,BorderLayout.SOUTH);
    }

    /**
    * @param args
    */
    public static void main(String[] args) {
        TestFrame frm = new TestFrame();
        frm.setSize(400, 400);
        frm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frm.setVisible(true);
    }

}

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Hi, thx for your effort again. Thats what I want :) I think i might need to take sometime for me to understand and migrate ur code to my program.

But somehow I tested ur code again and find out that if I remove 1 textfield, the other 1 won't work >

Code:

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textLostOnFocus.setText("This text will be lost on focus");

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Wonder is this the case that need to textfield? Can I have one instead? As previously I've tested with the code u give me earlier on also have the same problem with 1 textfield.

I told you, if the Frame has only 1 component. this component will be selected by default. so you gotta have at least 2 components on the Fram to have an inactive one

Quote:

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Originally Posted by ComputerJy

I told you, if the Frame has only 1 component. this component will be selected by default. so you gotta have at least 2 components on the Fram to have an inactive one

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Oic, thanks alot, you've been a great help :)

You are very welcome
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