从 JList 检索自定义对象

Question

I created a list and a model with custom objects. I want to retreive the objects that are in the list, however, I get an error message, that String can not be converted to Object.

String cannot be converted to ARMAJTermek

Swing automatically creates the JList, to which then I add a new model.

DefaultListModel model = new DefaultListModel<ARMAJTermek>();
TermekList.setModel(model);

I need this, because I'm using a custom object, that has properties and methods, which I need to invoke later. For this, I overrode the .toString method, like this:

@Override
    public String toString () {
        String toString = "";
        toString = this.nev+"\n"+this.cikkszam+"\n"+Integer.toString(this.bruttoKisker)+" Ft";
        return toString;
    }

This way, when I add an object to the JList, it appears as designed by the cell renderer (which is also unique, in a way that it displays JTextArea as a list element...).

for (int i... and lots of other code) {
    model.addElement(termek[i]);
}
TermekList.setModel(model);
TermekList.revalidate();
TermekList.repaint();

After adding objects to the list, it appears correctly, runs correctly, as when I select an object in the lists, it's methods run correctly. However, when I try to make a copy of the selected object for a different JList, I'm unable to retrieve them. I tried getting it from the list itself with

ARMAJTermek termek = (ARMAJTermek)TermekList.getSelectedValue();
ARMAJTermek termek = (ARMAJTermek)TermekList.getModel().getElementAt(TermekList.getSelectedIndex());

(Different functions, that's why some variables have the same name even being different types.)

But I get the message, that these Strings can not be converted to ARMAJTermek. But I don't need the String representation of the objects, I need the objects themselves. I mean, if it's methods can be run by clicking on their String representation in the list, I should be able to make a copy of them, right?

public class ARMAJTermek {
    String nev;
    String cikkszam;
    int bruttoKisker;

    public ARMAJTermek(String nev, String cikkszam, int bruttoKisker) {
        this.nev = nev;
        this.cikkszam = cikkszam;
        this.bruttoKisker = bruttoKisker;
    }

    @Override
    public String toString () {
        String toString = "";
        toString = this.nev+"\n"+this.cikkszam+"\n"+Integer.toString(this.bruttoKisker)+" Ft";
        return toString;
    }
}

public ui_main() throws  {
    initComponents();
    DefaultListModel model = new DefaultListModel<ARMAJTermek>();
    TermekList.setModel(model);

    ARMAJTermek termek[2];
    termek[0] = new ARMAJTermek("lorem", "ipsum", 1);
    termek[1] = new ARMAJTermek("lorem2", "ipsum2", 2);
}

public void addTermek(JList TermekList) {
    DefaultListModel model = new DefaultListModel<ARMAJTermek>();
    model.clear();
    if(TermekList.getSelectedIndex() == 0){
            TermekList.setSelectedIndex(1);
        }
    TermekList.removeAll();
    for ( int i = 0; i < termek.length; i++ ) {
        model.addElement(termek[i]);
    }
    TermekList.setModel(model);
        TermekList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);

        TermekList.revalidate();
        TermekList.repaint();
}

public void getTermek(JList TermekList) {
    ARMAJTermek termek = (ARMAJTermek)TermekList.getSelectedValue();
    ARMAJTermek termek = (ARMAJTermek)TermekList.getModel().getElementAt(TermekList.getSelectedIndex());
}

Answer 1

I made it run by creating a new function inside the function, that can take and store the ARMAJTermek object:

ARMAJTermek termek = ARMAStaticFunctions.getTermek(TermekList);

public static ARMAJTermek getTermek(JList TermekList) {
        ARMAJTermek termek = (ARMAJTermek)TermekList.getSelectedValue();
        return termek;
}

And now it works as intended, not trying to convert objects to String.