CODEWITHSUNDEEP
javaswingcombobox
yungaero
yungaero

Reputation: 1

ComboBox with own Objects

I'm trying to use a JComboBox to select between different Instances of a class written by myself, for which i have already implemented a renderer Class:

class BackupJobRenderer extends JLabel implements ListCellRenderer {
private static final Color HIGHLIGHT_COLOR = new Color(0, 0, 128);

public BackupJobRenderer() {
    setOpaque(true);
    setHorizontalAlignment(CENTER);
    setVerticalAlignment(CENTER);}

public Component getListCellRendererComponent(JList list, Object value,
                                              int index, boolean isSelected, boolean cellHasFocus) {
    BackupJob bjob = (BackupJob) value;
    setText(bjob.getName());


    if (isSelected) {
        setBackground(HIGHLIGHT_COLOR);
        setForeground(Color.white);
    } else {
        setBackground(Color.white);
        setForeground(Color.black);
    }
    return this;
}

When I'm trying to initialize the ComboBox like the following:

 //backMan.getArrayJobs returns an Array of BackupJobs
 comboBoxJobs = new JComboBox(backMan.getArrayJobs());
 comboBoxJobs.setRenderer(new BackupJobRenderer());
 comboBoxJobs.setMaximumRowCount(3);
 comboBoxJobs.setEnabled(true);

the ComboBox stays empty, although, according to the debugger, the Array's elements seem to be present in the ComboBox's "dataModel".

What am i doing wrong here?

Upvotes: 0

Views: 114

Answers (1)

Necromancer
Necromancer

Reputation: 919

Create DefaultComboBoxModel and put the array to this model like the following.

DefaultComboBoxModel model = new DefaultComboBoxModel<>(yourObjectArray);
JComboBox<Object> combo = new JComboBox<>(model);
combo.setRenderer(new BackupJobRenderer());

Your Renderer class should be : 

class BackupJobRenderer extends DefaultListCellRenderer {

public Component getListCellRendererComponent(......) {
JLabel label = (JLabel)super.getListCellRendererComponent(list,value,index,isSelected,cellHasFocus);

if(value !=null && value instanceof BackupJob) {
BackupJob backup = (BackupJob) value;
label.setText(backup.getName());


if (isSelected) {
    label.setBackground(HIGHLIGHT_COLOR);
    label.setForeground(Color.white);
} else {
    label.setBackground(Color.white);
    label.setForeground(Color.black);
}
}
return label;
}
}

Upvotes: 1

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