ArrayList consisting of JButtons. But doesn't work as expected

Question

I'm on a project right now and I'm trying out some new code to make my program more efficient. I was thinking of an ArrayList "dice" which will contain some buttons (that're supposed to be dice). If I for example array.add(die1) , I assume I can refer to the object in the array instead of the actual button.

For example: I can set the text of die1 as die1.setText(""); I would also like to do it to the object in the array directly so I can use loops, like, array.get(i).setText("") ;

But it doesn't work which is weird. If I do array.get(0).getClass() it says javax.Swing.JButton which seems to be right.

Java 11

ArrayList dice = new ArrayList<JButton>();


private void die1ActionPerformed(java.awt.event.ActionEvent evt) {                                     
    // TODO add your handling code here:
    if (die1.getBackground() == Color.red) {

        dice.remove(dice.indexOf(die1));
        die1.setBackground(Color.green);
    }
    else {
        dice.add(die1);
        die1.setBackground(Color.red);            
    }
}     

private void btnRollActionPerformed(java.awt.event.ActionEvent evt) {                                        
    // TODO add your handling code here:

    for (int i = 0; i < dice.size(); i++) {

        int random = roll();

        dice.get(i).setText(""+random); //This displays as error; uncompilable

    }
}      

Expected: to work. But naturally it can't compile and crashes.

Answer 1

Because you haven't typed the declaration of your List.

Try this:

List<JButton> dice = new ArrayList<>();