CODEWITHSUNDEEP
javaswingjlist
benscabbia
benscabbia

Reputation: 18072

Java JList remove() method throws an ArrayOutOfBoundsException

I'm using a JList which displays correctly. However, I'm having trouble removing elements from the list. 

JList nameList = new JList(db.getAllNames());
nameList.setVisibleRowCount(6);
nameList.setFixedCellWidth(400);

JButton removeNameButton = new JButton("Remove Name");

removeNameButton.addActionListener(new ActionListener(){
    public void actionPerformed(ActionEvent e) {
        String id = nameList.getSelectedValue().toString(); //valid value when button pressed
        int index = nameList.getSelectedIndex(); //valid value when value pressed

        namesList.remove(index); //ERROR
    }

The JList contains 4 names, which displays perfectly and seem to have the correct indexes. (If I check the value System.out.println(copiersList.getModel().getSize()); it always displays 4

Here is the error message:

Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 3

Oddly, if I remove Adam, I do not get an error (but visibly the list does not change and calling .getSize() method displays 4):

enter image description here

id selected: Adam
index selected: 0

However, any other:

id selected: BobException in thread "AWT-EventQueue-0" 
index selected: 1
java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 1
at java.awt.Container.remove(Unknown Source)

Upvotes: 2

Views: 1513

Answers (1)

Hovercraft Full Of Eels
Hovercraft Full Of Eels

Reputation: 285401

Don't remove from the JList itself since the remove(...) method does not do what you think that it does. It in fact is trying to remove a component that is held in the JList as if it were a JPanel that held other components, even if no such component exists. Instead remove from the JList's model, usually a DefaultListModel. The DefaultListModel class has a removeElement(Object element) and a removeElementAt(int index) method that can help you.

i.e.,.

public void actionPerformed(ActionEvent e) {
    String id = nameList.getSelectedValue().toString(); //valid value when button pressed
    int index = nameList.getSelectedIndex(); //valid value when value pressed

    DefaultListModel listModel = (DefaultListModel) namesList.getModel();
    listModel.removeElementAt(index); 
}

Upvotes: 4

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