So from your description, you have a panel that is not visible, that you would like to appear if the combobox is clicked? So it will appear for any option in the combobox?
That should be simple enough. Lets modify the JLabel
in this ComboBoxDemo from the Java Tutorials. Since they both inherit from JComponent
, we will be able to make the JLabel
and the JPanel
visible in the same way.
First, make sure you understand what the demo is doing. The Combobox options are changing the format of the date's text in the JLabel. We want to edit the demo in such a way that this JLabel is not visible until after we select any option in our JComboBox.
First, we will want to include a boolean as a class variable, so that we can access it in any of our methods.
boolean visibleComp;
Next, in the constructor, you will want to change the JLabel "result" to be invisible by default. We can do this by using the setVisible method of the JComponent.
result.setVisible(false);
Now we need to control when and how result becomes visible -- as we continue through the code, we see that the actionPerformed
method handles our events, and passes the formatting details off to another method called reformat.
Since reformat is also called in our constructor, we will want to set our boolean value in the actionPerformed method.
visibleComp = true;
We will then want to add a conditional statement to the try block in reformat -- this will check to see if our boolean is true, which would only occur if an action had been performed by the user. We can use this to set our component's visibility.
if(visibleComp){
result.setVisible(true);
}
You can easily interchange a JPanel with this example. Hope that helps.