Auto Select

[_lithium_]

How do you utilize the AutoSelect class after you make it?

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.text.*;
public class AutoSelect extends FocusAdapter {
		public void focusGained(FocusEvent e)
		{
			if (e.getComponent() instanceof JTextField)
			{
				JTextField t = (JTextField) e.getComponent();
				t.selectAll();
			}
		}
	}

I need to have the text field called scoreTextField be able to be auto highlighting the data in the field automatically but can't figure out how to implement it.

[javapenguin]

If it's an instance of JTextField, why cast it at all? (Maybe I'm wrong here.)

You're selecting all the text, but it appears you're doing nothing with it.

Anyway, you can set the background color by t.setBackground(Color.Whatever);

I found a class to Highlight.

As for automatically doing it, maybe one of these classes will help.
Java 2 Platform SE v1.3.1: Class DefaultHighlighter
If not, you could always have like an invisible component, a JButton or something like that and give it a Listener and tell it to like button.doClick() or item.setSelected(), or something like that.

Edit: Ok. I guess the if loop is to keep it from casting something that's not a JTextField. Keep the cast.
Anyway, I've always wondered how to get a Highlighter to work myself.

[DavidFongs]

If it's an instance of JTextField, why cast it at all? (Maybe I'm wrong here.)

You are. e.getComponent() returns an object of type Component. Without the cast, there is a compiler error

[_lithium_]

Yeah, the goal of this is to just to give focus to the textfield so the user can automatically start typing into the field instead of having to click it and manually delete the text already there. I just don't know how to implement it to always give focus to the textfield with the text in it already highlighted (thus you can start typing and it deletes the previous text)

[copeg]

Yeah, the goal of this is to just to give focus to the textfield so the user can automatically start typing into the field instead of having to click it and manually delete the text already there. I just don't know how to implement it to always give focus to the textfield with the text in it already highlighted (thus you can start typing and it deletes the previous text)

If the goal is to just give the JTextField focus, call requestFocus() on the component.

[_lithium_]

"Create an AutoSelect class at the end of this StudentsScoresApp class that highlights all of the data in the scoreTextField when the mouse is clicked on that TextField. That way, the user doesn’t have to manually highlight the preceding score just to enter a new score."

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.text.*;
import java.lang.Math;
 
public class StudentScoresApp	{
    public static void main(String[] args)	    {
 
		System.out.println("  List of Student Scores Entered");
        JFrame frame = new StudentScoresFrame();
        frame.setVisible(true);
    }
}
 
class StudentScoresFrame extends JFrame		{
    public StudentScoresFrame()		{
        setTitle("Test Scores");
        setSize(250, 250);
        centerWindow(this);
        setResizable(false);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JPanel panel = new StudentScoresPanel();
        this.add(panel);
    }
private void centerWindow(Window w) {
	Toolkit tk = Toolkit.getDefaultToolkit();
	Dimension d = tk.getScreenSize();
	setLocation((d.width-w.getWidth())/2, (d.height-w.getHeight())/2);
	}
}
 
class StudentScoresPanel extends JPanel implements ActionListener	{
    private JTextField  scoreTextField,
                        countTextField,
                        averageTextField,
                        bestTextField,
                        lowestTextField;
    private JLabel      scoreLabel,
                        countLabel,
                        averageLabel,
                        bestLabel,
                        lowestLabel;
    private JButton     enterScoreButton,
    					clearButton,
                        exitButton;
 
	private int count = 0;
 
	private double total = 0;
 
	// total is a double to prevent truncation when
	// calculating the average
	private double average = 0;
	private int best = 0;
	private int lowest = 100;
 
    public StudentScoresPanel()	   {
        // display panel
        JPanel displayPanel = new JPanel();
        displayPanel.setLayout(new FlowLayout(FlowLayout.RIGHT));
 
 
        // score label
        scoreLabel = new JLabel("Test score:");
        displayPanel.add(scoreLabel);
 
        // score text field
        scoreTextField = new JTextField(10);
        displayPanel.add(scoreTextField);
        scoreTextField.requestFocus();
        scoreTextField.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				scoreTextField.selectAll();
			}
		});
 
        // count label
        countLabel = new JLabel("Number of scores:");
        displayPanel.add(countLabel);
 
        // count text field
        countTextField = new JTextField(10);
        countTextField.setEditable(false);
        countTextField.setFocusable(false);
        displayPanel.add(countTextField);
 
        // average label
        averageLabel = new JLabel("Average score:");
        displayPanel.add(averageLabel);
 
        // average text field
        averageTextField = new JTextField(10);
        averageTextField.setEditable(false);
        averageTextField.setFocusable(false);
        displayPanel.add(averageTextField);
 
        // best label
        bestLabel = new JLabel("Highest score:");
        displayPanel.add(bestLabel);
 
        // best text field
        bestTextField = new JTextField(10);
        bestTextField.setEditable(false);
        bestTextField.setFocusable(false);
        displayPanel.add(bestTextField);
 
        // lowest label
        lowestLabel = new JLabel("Lowest score:");
        displayPanel.add(lowestLabel);
 
        // lowest text field
        lowestTextField = new JTextField(10);
        lowestTextField.setEditable(false);
        lowestTextField.setFocusable(false);
        displayPanel.add(lowestTextField);
 
        // button panel
        JPanel buttonPanel = new JPanel();
        buttonPanel.setLayout(new FlowLayout(FlowLayout.RIGHT));
 
        // enter score button
        enterScoreButton = new JButton("Enter Score");
        enterScoreButton.addActionListener(this);
        buttonPanel.add(enterScoreButton);
 
        // clear button
        clearButton = new JButton("Clear");
        clearButton.addActionListener(this);
        buttonPanel.add(clearButton);
 
        // exit button
        exitButton = new JButton("Exit");
        exitButton.addActionListener(this);
        buttonPanel.add(exitButton);
 
        // add panels to main panel
        this.setLayout(new BorderLayout());
        this.add(displayPanel, BorderLayout.CENTER);
        this.add(buttonPanel, BorderLayout.SOUTH);
    }
 
 
    public void actionPerformed(ActionEvent e)	{
        Object source = e.getSource();
        if (source == exitButton){
        	if (count == 0){
				lowest = 0;}
 
			NumberFormat ef = NumberFormat.getNumberInstance();
            ef = new DecimalFormat("###.00");
			System.out.println("\n  Highest: " + best + "  Lowest: " + lowest + "  Average: " + ef.format(average) + "\n");
 
				System.out.printf("  Program terminated by the User.");
 
            System.exit(0);
		}
      else if (source == enterScoreButton)	{
            // parse the score
            int score = Integer.parseInt(scoreTextField.getText());
			// calculate the results
            total += score;
            count++;
            average = total / count;
            if (score > best)
            	best = score;
 
            if (score < lowest)
            	lowest = score;
 
			NumberFormat df = NumberFormat.getNumberInstance();
            NumberFormat nf = NumberFormat.getNumberInstance();
            df = new DecimalFormat("###.00");
            countTextField.setText(nf.format(count));
            averageTextField.setText(df.format(average));
            bestTextField.setText(nf.format(best));
            lowestTextField.setText(nf.format(lowest));
            System.out.println("  " + nf.format(count) + ". " + score);
			scoreTextField.selectAll();
        }
        else if (source == clearButton)		{
			if (count == 0)
				lowest = 0;
			NumberFormat df = NumberFormat.getNumberInstance();
            df = new DecimalFormat("###.00");
			System.out.println("\n  Highest: " + best + "  Lowest: " + lowest + "  Average: " + df.format(average) + "\n");
			System.out.println("  Scores were cleared...\n  Next Set:");
			count = 0;
			total = 0;
			average = 0;
			best = 0;
			lowest = 0;
 
            scoreTextField.setText("");
			countTextField.setText("");
            averageTextField.setText("");
            bestTextField.setText("");
            lowestTextField.setText("");
		}
    }
}

[javapenguin]

Now I get what you wanted.

Here's what you should do.

Create a class called AutoSelect that has a static method that takes a textField(or TextArea), whichever you're using , and selects it. I don't know why so I'm taking a JTextComponent, which is the superclass of JTextArea and JTextField anyway, as a parameter.

public class AutoSelect()
{
 
public static void selectAll(JTextComponent jtc)
{
jtc.selectAll();
}

And later, in your class with the JTextComponent,

JTextComponent whatever = new JTextComponent();
 
whatever.addMouseListener(new MouseListener() {
 
// implement Mouse Listener methods.
// for moused clicked 
// AutoSelect.selectAll(whatever);
});

Try that.

[javapenguin]

Change it to JTextField if you want, though it'll still work as JTextComponent as parameter for the static method. In fact, the way I have it, it'll work with JTextAreas too.

[javapenguin]

I don't know why you can't just tell it to selectAll() in the MouseListener without even bothering with another class. But if you must, what I posted should work.

[_lithium_]

Yeah I tried the above coding and it didn't seem to work, It keeps saying "StudentScoresApp.java:149: '{' expected
public class AutoSelect()"
^

I implemented this:

		  	scoreTextField.addFocusListener(new java.awt.event.FocusAdapter() {
		      public void focusGained(java.awt.event.FocusEvent evt) {
		          scoreTextField.selectAll();
		      }
			});

within the "Enter Score" button and it seems to perform the same function but doesn't generate the "AutoSelect.class" that is wanted. (it says StudentScoresApp.java should generate that .class file.

[_lithium_]

I'm completely confused on this portion still, I got it to the point where it generates an autoselect.class when the app is ran but can't figure out where/how to use it... in the main app:

 class AutoSelect extends FocusAdapter {
	public void focusGained(FocusEvent e)
			{
				if (e.getComponent() instanceof JTextField)
				{
					JTextField t = (JTextField) e.getComponent();
					t.selectAll();
				}
			}
	}

I've tried doing something like this within the panel:

        // score text field
        scoreTextField = new JTextField(13);
        displayPanel.add(scoreTextField);
        AutoSelect.focusGained(scoreTextField);

I just need to have the scoreTextField have all the text selected once it is clicked just once.

[_lithium_]

How do I call to an inner class like the above example code?

[copeg]

Check the API for JTextField, in particular the addFocusListener method, and suggested reading: How to write a FocusListener

[_lithium_]

I've tried that. I think the focus listener doesn't have what i'm looking for.

::Edit::

I think all I need to do is know how to pass to this now:

 class AutoSelect extends  MouseAdapter {
	public void mouseClicked(MouseEvent e)
			{
				if (e.getComponent() instanceof JTextField)
				{
					JTextField t = (JTextField) e.getComponent();
					t.selectAll();
				}
			}
	}

i can't seem to figure out how to because I don't knwo how to pass to it and also where in my code to do so.

I just need it to auto select all the text in the JTextfield once the box is clicked once, instead of the user having to highlight it all them selves and delete it.

[vezon]

maybe u already found your answer.
just like the u added the actionlistener to the buttons u have to add the focuslistener to the objects.
scoreTextField.addFocusListener(new AutoSelect())

By the way its much better to use focuslistener then mouselistener in this case. U will have autoselecteted text even with keyboard navigation.
I hope u understand whats the difference between the way u implemented the focuslistener (through an adapter) and the actionListener.
and why u used the button.addactionlistener(this)

I was looking on a more elegant way to implement this behaviour to all my Objects on the form without extending every type of object, or
add the focuslistener to every object.