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Java JList issue

Posted on 2011-09-12
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Last Modified: 2012-05-12
I've added the following code to a JList and am now unable to select individual items in the list

Any Ideas? For reference getANZIC returns a string value
@SuppressWarnings("serial")
class MyCellRenderer extends JLabel implements ListCellRenderer {

public Component getListCellRendererComponent(
      JList list,
      Object value,            // value to display
      int index,               // cell index
      boolean isSelected,      // is the cell selected
      boolean cellHasFocus)    // the list and the cell have the focus
    {
	
    
        setText(((Occupation)value).getANZIC());
        return this;
    }
}

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Question by:CloudStrife209
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7 Comments
 
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Expert Comment

by:for_yan
ID: 36526932


>I've added the following code to a JList

Please, post your code the part were you craete the list and set the renderer
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Author Comment

by:CloudStrife209
ID: 36526937
here you go
JList listing = new JList(occupationList);
listing.setCellRenderer(new MyCellRenderer());

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LVL 47

Expert Comment

by:for_yan
ID: 36526953
What means unable to select?
How do you judge that it is not selecting?

Can you post more of your code so that I copuld try
to run it myself?
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LVL 47

Expert Comment

by:for_yan
ID: 36527024
It would work if you extend DefaultListCellRenderer.
Try this code:

import javax.swing.*;
import java.awt.*;
import java.util.ArrayList;
import java.util.Vector;

public class JListTest extends JFrame {

    public JListTest() {
        super("test");

        Vector<Occupation> ar = new Vector<Occupation>();
      ar.add(new Occupation("MD"));
       ar.add(new Occupation("PD"));
       ar.add(new Occupation("LD"));

        JList l = new JList(ar);
        l.setCellRenderer(new MyCellRenderer());

        Container c = this.getContentPane();
        c.add(l);

        this.setSize(300,300);
        this.setVisible(true);





    }

    public static void main(String[] args) {
        new JListTest();
    }

}
class Occupation {
    String text;

    Occupation(String s){
        text = s;
    }

    public String toString(){
        return text;
    }

}

@SuppressWarnings("serial")
class MyCellRenderer extends  DefaultListCellRenderer{

public Component getListCellRendererComponent(
      JList list,
      Object value,            // value to display
      int index,               // cell index
      boolean isSelected,      // is the cell selected
      boolean cellHasFocus)    // the list and the cell have the focus
    {

          System.out.println("value: " + value);
          System.out.println(isSelected);
           System.out.println(cellHasFocus);

        if(isSelected)this.setBackground(Color.blue);
        else    this.setBackground(Color.white);
       this.setText(((Occupation)value).toString());
        return this;
    }
}

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Accepted Solution

by:
for_yan earned 500 total points
ID: 36527059
This is another variant how it works:

import javax.swing.*;
import java.awt.*;
import java.util.ArrayList;
import java.util.Vector;

public class JListTest extends JFrame {

    public JListTest() {
        super("test");

        Vector<Occupation> ar = new Vector<Occupation>();
      ar.add(new Occupation("MD"));
       ar.add(new Occupation("PD"));
       ar.add(new Occupation("LD"));

        JList l = new JList(ar);
        l.setCellRenderer(new MyCellRenderer1());

        Container c = this.getContentPane();
        c.add(l);

        this.setSize(300,300);
        this.setVisible(true);





    }

    public static void main(String[] args) {
        new JListTest();
    }

}
class Occupation {
    String text;

    Occupation(String s){
        text = s;
    }

    public String toString(){
        return text;
    }

}



class MyCellRenderer1 extends JLabel implements ListCellRenderer {

  public MyCellRenderer1() {
    setOpaque(true);
  }

  public Component getListCellRendererComponent(JList list, Object value, int index,
      boolean isSelected, boolean cellHasFocus) {
    setText(value.toString());

    if (isSelected) {
      setBackground(list.getSelectionBackground());
      setForeground(list.getSelectionForeground());
    } else {
      setBackground(list.getBackground());
      setForeground(list.getForeground());
    }
    return this;
  }
}

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Expert Comment

by:for_yan
ID: 36527075
This is based on your code and it is working.

You of course need to add if(isSelected)... else
and another thing which turns out to be impiortnat
is setOpaque(true) in the constructor.

import javax.swing.*;
import java.awt.*;
import java.util.ArrayList;
import java.util.Vector;

public class JListTest extends JFrame {

    public JListTest() {
        super("test");

        Vector<Occupation> ar = new Vector<Occupation>();
      ar.add(new Occupation("MD"));
       ar.add(new Occupation("PD"));
       ar.add(new Occupation("LD"));

        JList l = new JList(ar);
        l.setCellRenderer(new MyCellRenderer());

        Container c = this.getContentPane();
        c.add(l);

        this.setSize(300,300);
        this.setVisible(true);





    }

    public static void main(String[] args) {
        new JListTest();
    }

}
class Occupation {
    String text;

    Occupation(String s){
        text = s;
    }

    public String toString(){
        return text;
    }

}




class MyCellRenderer extends JLabel implements ListCellRenderer {
     public MyCellRenderer() {
    setOpaque(true);
  }

public Component getListCellRendererComponent(
      JList list,
      Object value,            // value to display
      int index,               // cell index
      boolean isSelected,      // is the cell selected
      boolean cellHasFocus)    // the list and the cell have the focus
    {
         
         if (isSelected) {
      setBackground(Color.blue);
      setForeground(Color.black);
    } else {
      setBackground(Color.white);
      setForeground(Color.black);
    }

        setText(((Occupation)value).toString());
        return this;
    }
}

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Author Closing Comment

by:CloudStrife209
ID: 36527082
Thanks
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