kind of Component being return? and Conversion

[mine0926]

1. Is there anyway to know the kind of Component is being return? At focusGained event I would like to know it kind of control.
2. Convert component or Object to a JTextField?

highlightText has a parameter of JTextField:

public static void highlightText(javax.swing.JTextField ctr){
        ctr.setSelectionColor(Color.BLUE);
        ctr.setSelectedTextColor(Color.WHITE);
        ctr.setSelectionStart(0);
        ctr.setSelectionEnd(ctr.getText().length());
 }

so if I get the source or component that has focus and pass it to highlightText

private void focusGained(java.awt.event.FocusEvent evt){
    // Here: if evt.getSource() is JTextField then
    // evt.getSource() should be converted or validated as JTextField
     if (evt.getSource().getClass().getComponentType() == javax.swing.JTextField){
        FormUtilities.highlightText(evt.getSource());
    }
}

then Error will occur because parameter and passed value are not the same kind

    method highlightText cannot be applied to given types

Also, I get error in IF statement

Cannot find symbol
symbol: class swing
location: package javax

Thanks for always helping me,
geje

[r035198x]

instanceof is the cookie that you want

if (evt.getSource() instanceof JTextField) {
	JTextField textField = (JTextField) evt.getSource();
}

[mine0926]

Thanks for you reply.

I got new error now, it says
frmMain is not abstract and does not override abstract method focusLost(java.awt.event.FocusEvent)
in java.awt.event.FocusListener

here is the code

public class [b][u]frmMain[/u][/b] extends javax.swing.JFrame implements FocusListener {
    public frmMain() {
        initComponents();
        ControlProperties();
        ControlResize();
    }
    public void focusGained(java.awt.event.FocusEvent e) {
        if (e.getSource() instanceof JTextField){
            JTextField source = (JTextField) e.getSource();
            System.out.println(source);
            FormUtilities.highLightText(source);
        }
    }

Thanks,
geje

[mine0926]

ok I already solve it. I just add focusLost. Thanks again

[Tolls]

This is why I think the highlight code ought to be on an extended JTextField.

[r035198x]

Unless if they are going to need similar functionality with other text components.

[Tolls]

Possibly, but it seems a bit untidy to me.
As does the hard-coded colours, but that's another thing entirely.

It just doesn't look like a utility method...but maybe that's just me.

[mine0926]

Hi,

Thanks for you help but highLightText() does not highlight JTextField whenever they got the focus.

Possibly, but it seems a bit untidy to me.
As does the hard-coded colours, but that's another thing entirely.

It just doesn't look like a utility method...but maybe that's just me.

Can you suggest code that will make it more cleaner?


Thanks for pointing me on my errors.

[Tolls]

The code you posted implied that you had JTextFields that would get their text highlighted on gaining focus.

To do this you've created a static method, which takes a JTextField and highlights the text.

Now, my argument is that it is specific to JTextFields (or at least certain JTextFields) and it makes no sense to detach it from them like that. r035198x has a good point about simply extending JTextField possibly not being a good idea (I forgot there were child classes)...but I still argue that it should be encapsulated in some way.

So...some sort of HiglightJTextField, which is simply a wrapper around a JTextField, that holds both the FocusListener and the highlightField() method.

public class HiglightField {
    private JTextField field;
    // some constructor(s), which create the field and attach a focus listener that calls our own
    // highlight method.
    
    private void highlightText() {
    }
    
    public JTextField getField() {
        return field;
    }
}

// useage.
{
    HiglightField myField = new HiglightField();
    myPanel.add(myField.getField());
}

What you gain is code that is tied to the thing it is supposed to be working on, and not scattered around the place.
Your panel or form doesn't care about highlighting text, so it shouldn't have to actually deal with it.
And since "highlighting text" is (in my mind) something that the field does, then the code for that should be with the field.

Now I sit back and wait for the above to be picked apart...:)

[mine0926]

Hi,

I am sorry if I reply to this thread too long. Anyway, I cannot try the given
code by yours because the focusGained event does not fire. I try to put
System.out.println(e.getSource()); under focusGained event to know if it
is working. Everytime I click a JTextField it does not do anything.

    public void focusGained(FocusEvent e) {
        System.out.println(e.getSource());
        if (e.getComponent() instanceof JTextField){
            //JTextField source = (JTextField) e.getSource();
            //FormUtilities.highLightText(source);
            System.out.println(e.getSource());
            //HiglightField myField = new HiglightField();
            //frmMaterials.add(myField.getField());
        }
    }

focusGained event is place at:

public class frmMain extends javax.swing.JFrame implements FocusListener {
    public frmMain() {
        initComponents();
        ControlProperties();
        ControlResize();
    }
    public void focusGained(FocusEvent e) {
        System.out.println(e.getSource());
        if (e.getComponent() instanceof JTextField){
            //JTextField source = (JTextField) e.getSource();
            //FormUtilities.highLightText(source);
            System.out.println(e.getSource());
            //HiglightField myField = new HiglightField();
            //frmMaterials.add(myField.getField());
        }
    }

    public void focusLost(FocusEvent e) {
        //do nothing
    }

Thanks,
geje

[mine0926]

I got it working. Sometimes it is good to share your problems because it help you analyze the code more. I've been solving it for days but after I post it I notice that I did not put jTextField1.addFocusListener(this); that is why it does not fire focusGained event.

TO Toll:
If you dont mind can you give me a link where it explains what you did on your code?

I got errors at your given code and I want to debug it and learn it.


Thanks again,
geje

[Tolls]

The code as posted is only an example.
I'm not surprised it doesn't compile...it's not supposed to.
You'll have to figure out how it wires together, I'm afraid...shouldn't be difficult, it's just a wrapper.