CODEWITHSUNDEEP
javaswingjcombobox
j0chn
j0chn

Reputation: 1113

Java Swing JComboBox select only available item

I have a JComboBox with only one item. When I populate this item to the Box I immediately select it with combobox.setSelectedItem(item). But unfortunately I get -1 / null when I read the item with combobox.getSelectedIndex(0) or combobox.getSelectedItem(item).

Sure I know which Item is in the box but I don't want to add a statement to react to that case.

Can you tell me how I can read the lone Item in the combobox?

Upvotes: 1

Views: 555

Answers (1)

Lajos Arpad
Lajos Arpad

Reputation: 76426

Problem

combobox.setSelectedItem(item) takes item as an Object and checks it among the items. Since combobox.getSelecedIndex returns -1, we already know that there is no selection, therefore your selection was unsuccessful.

Reason

You passed an object to setSelectedItem, but that Object was not found among the items. It is easily possible that your Object is a String and you are passing a similar String as a parameter, but the parameter you are passing is not the same String, bug similar.

Behavior test

String foo = "bar";
boolean theSame = (foo == "bar"); //false
boolean similar = foo.equals("bar"); //true

Solution

Use the same Object when you call setSelectedItem instead of a similar Object.

Upvotes: 3

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