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JList setSelectedValue not working

I have a JList in Swing working bad. I list all items from Database into the list with no problem with this code.
My code:
Integer index = null;
DefaultListModel<String> model = new DefaultListModel<String>();
index = DataBase.getIndex1(cbActivity.getSelectedItem().toString());
activities = DataBase.getIndex2(index);
for(MapActivity mapActitivy : activities)
{
model.addElement(mapActivity.getActivity().toString());
}
jList.setModel(model);
But now, I would like to select individual or multiple selection, but nothing I tried works. I tried:
jList.setSelectedValue("Ball", true);
//jList.setSelectedIndex(2);
jList.setSelectionBackground(Color.red);
But nothing happen. Just the list on screen with nothing selected. Single or multiple.
Any help?

Try this:
setSelectedIndex(1); // here use index of items
or if it does not work use below one:
setSelectedItem("ball") // here use name of item.

Populating JComboBox using an MultiDimensional Array List

I have been trying to populate a Eclipse GUI Java JComboBox using an Array list using constructors without any luck. This is what I have tried thus far.
import item.Item;
import javax.swing.JComboBox;
import java.util.ArrayList;
public class SelectionScreen{
private JFrame frame;
static ArrayList< Item> list;
private String items;
public static void main (String[] args){
initialize();
}
public void initialize(){
list = new ArrayList< Item >();
list.add(new Item("Strawberry,200,.25,.75);
list.add(new Item("Banana,200,.25,1.00);
list.add(new Item("Oranges,200,.25,2.00);
JcomboBox comboBox = newJcomboBox();
ComboBox.setBounds(63,29,86,22)
frame.getContentPane().add(comboBox);
// here is where I tried to fill the combobox
//comboBox.setModel(new DefaultComboBoxModel(Item.getName()))); //Wrong
//comboBox.setModel(Item.getName); //Wrong
//the following only loads the last item in the list which is Oranges
for(Item i: list{
comboBox.setModel(new DefaultComboBoxModel(New String[] {
i.getName()}));
}
// tried making a different list to collect my fruits.
for(Item i: list){
list2[ i.getName()];
Item.length;
} //which was a complete fail.
I am at complete lost here and not very experienced with Java. I can load the items just fine using
comboBox.setModel(new DefaultComboBoxModel(new String[]{ "Strawberry","Banana","Oranges"}));
but I won't know what fruits are in the list when I import them from a text file.
Any help would be appreciated.

/*The following only loads the last item in the list which is Oranges.*/
for(Item i: list)
{
comboBox.setModel(new DefaultComboBoxModel(new String[] {
i.getName()}));
}
Don't keep creating a new ComboBoxModel inside the loop. You can't add more than one item to the model if you keep creating a new model. So you only see the last model created with the single item added to it. If you want to use this approach then you would create the model OUTSIDE of the loop and then just add items the model INSIDE the loop.
Actually you don't event need to create a combo box model. You can just add items directly to the combo box:
Something like:
for(Item i: list
{
comboBox.addItem( i.getName() );
}
Another option is to add the Item object directly to the combo box. Then you can use a custom renderer to control which property of the Item object is display in the combo box. Check out Combo Box With Custom Renderer for more information on this approach.

If you wish to show Item objects in a combobox then you should declare the JComboBox to store Item objects. That way you can easily add items without having to do any mucking around with models at all:
JComboBox<Item> itemsCombo = new JComboBox<>();
list.forEach(itemsCombo::add);
The value displayed in the combobox will be whatever is returned by Item.toString. If that's not what you want (because your toString returns a more complete description of the object - generally considered better practice) then it is fairly easy to write your own Custom Renderer.
The only hackish downside of the JComboBox API is that you've got to cast the selected item:
Item selectedItem = (Item)itemsCombo.getSelectedItem();
This is ugly and I wish the API didn't require it but it's a small price to pay to avoid having to define your own model.
You can, in fact, avoid the cast by:
Item selectedItem = itemsCombo.getItemAt(itemsCombo.getSelectedIndex());
But that's just about as ugly.
As an aside, this is one of several areas in which the standard Java tutorial and samples are quite out of date so there's no blame here at all for not knowing to use generics.

Fetch array of strings from ArrayList for JList Java

the task which I do is quite simple, but I faced one problem with JList component.
What i need is. I fetch data from DataBase, load it to String array, pack array into ArrayList (just because I duno how many records I have), return it from method as ArrayList.
Now at receiver side. I have a trouble, I cant fetch String array from ArrayList so that I can pass to JList.
Here is the code.
ArrayList<Object> fetch = new ArrayList<Object>();
public String[] data =new String[10];
listModel = new DefaultListModel();
myList = new JList(listModel);
//myList = new JList(data);
// So it works with simple array of strings.
fetch=DAO.loadPasswords();
//At this point it asks me to cast an object to smth which late cause null pointer exception.
myList = new JList(fetch.get(0));
And here is loadPasswords();
public static ArrayList<Object> loadPasswords(){
dbConnect();
boolean unswer = false;
String[] result=null;
String query1 = "select * from tblPasswordsStorage where "
+ "_user_id = ?";
String userId=Personal_Organizer.userProfile.getUserID();
ArrayList<Object> params = new ArrayList<Object>();
params.add(userId);
executeQueryP(query1, params);
ArrayList<Object> fetched=null;
try {
if (rs.next()) {
unswer = true;
//Personal_Organizer.userProfile.setUserID(rs.getString(1));
result[0]=rs.getString(1);
result[1]=rs.getString(2);
result[2]=rs.getString(3);
result[3]=rs.getString(4);
result[4]=rs.getString(5);
result[5]=rs.getString(6);
result[6]=rs.getString(7);
result[7]=rs.getString(8);
result[8]=rs.getString(9);
result[9]=rs.getString(10);
fetched.add(result);
}
if (unswer) {
while (rs.next()) {
Tools.print(rs.getString(1));
}
}
} catch (SQLException ex) {
JOptionPane.showMessageDialog(null,
"SQL Server connection issue.\n"
+ "Please, check Server address, user name and password.",
"Output",
JOptionPane.PLAIN_MESSAGE);
}
dbClose();
return fetched;
}
I tried to use multidimensional array but still JList require single dimensional array.

Either use a DefaultListModel and load it with your Strings using a simple for or for-each loop that loops through your ArrayList, adding each String item in the ArrayList into the model, or create your own ListModel class, one that extends AbstractListModel and that uses the ArrayList as its data nucleus.
Edit, since your data is held in an ArrayList of arrays, then perhaps you don't want to display it within an ArrayList after all, but rather in a JTable. Here your best bet would be to create your own TableModel, one based off of AbstractTableModel and that uses your ArrayList as its data nucleus. Also, perhaps better than loading your data into an array would be to create a custom class to hold each row of data from the ResultSet.
You state:
My problem is to simply load something to JList. The idea is to display application/website name in the list, then when you click on it, you get full data which contains in array. That's why I put fetch.get(0)...because. I need at least something.
Then
Create a custom class to hold each row of data.
Create items of this class from each row of the ResultSet
Fill your DefaultListModel with items of this class
Give your JList a custom ListCellRenderer, one that display's the application/website name
Then you can display the name and still have each list item hold all the pertinent information that it needs.

Loading an ArrayList into a JCombobox using netbeans

Currently have an ArrayList called SundayList which is loaded as soon as the frame AddStudent is loaded (bit of GUI)
The code automatically generated by Netbeans is:
comboboxSunday = new javax.swing.JComboBox();
comboboxSunday.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Item1", "Item2" }));
How do I load the combobox items with my own array?
The array includes items such as:
Activity1
Activity2
Activity3
Activity4
From my previous search, people mentioned about using a toString() and toArray(), and I'm not familiar with either methods, and how they help in loading the list into the combobox as I'm quite new to java..

You could create your own ComboBoxModel that takes a List as the main parameter, but that's a little more involved
comboboxSunday.setModel(new DefaultComboBoxModel());
for (Object item : listOfItems) {
comboboxSunday.addItem(item);
}

Assuming your array looks something like this:
String[] SundayList = { "Activity1", "Activity2", "Activity3", "Activity4" };
You can do this:
javax.swing.JComboBox sundayCombo = new javax.swing.JComboBox(SundayList);
If your array isn't a string array. try:
javax.swing.JComboBox sundayCombo = new javax.swing.JComboBox(SundayList.toString());
Hope this helps!

How to populate an Object[] with items

I'm trying to use a Swing Dialog so that the user can choose an item from a list of options with poolTeams being the name of that list. Like this:
String team = (String)JOptionPane.showInputDialog(frame, "Please choose a team:\n",
"Choose Team", JOptionPane.PLAIN_MESSAGE, null, poolTeams, "");
According to the documentation, poolTeams needs to be of type Object[] so I can't use ArrayLists or anything like that.
The problem is; the items in poolTeams will vary so I can't just populate it like
Object[] poolTeams = {"a", "b", "c"};
Is there a way I can make the program populate it automatically? If not, is there a different way I can offer the user a list in the dialog box?
Thanks!

List<Object> options = new ArrayList<Object>();
options.add(...);
options.add(...);
options.add(...);
Object [] selections = options.toArray()

You can very easily turn an ArrayList to an array using the toArray() method. Build up your ArrayList, then turn it into an array when you need it.