Question

HI all,

I’m trying to write a simple star rating component. I’m fairly new to the Java language and I’m not sure if what i want to accomplish can even be done in Java. Is it possible for me to add a JLabel inside an array of JLabel, and each JLabel in the array will have a mouse event listener. Now is it possible to set it up so that when the mouse event fires on say Label[3] that i can get the index value of it?

Here is how I built my Panel

public Rating(Integer max,int size) {

JLabel  position = new JLabel[max];


    this.setLayout(new FlowLayout());
    for(int i=0; i != max;i++){
    position[i]=new JLabel(icons.getIcon("star-empty", size));
    position[i].setOpaque(true);
    position[i].addMouseListener(this);
    add(position[i]);
    }
}


@Override
public void mouseEntered(MouseEvent e) {
    JLabel a= (JLabel) e.getComponent();
    //****Have some code in here to tell me where in the position array the event came from????***
    int index = ?????
   }

Thoughts/Idea/Suggestions please.

Note I thought of using buttons, but it looks messy and would love to find a way with ImageIcons.

THanks.

Answer 1

Instead of using the same listener for each label like you did:

position[i].addMouseListener(this);

…you can create a special listener class that takes the index number, and allows you to find it later:

position[i].addMouseListener(new RatingMouseListener(i));

Each label will have a separate instance of the listener with a different index value. The code for the inner class would look like something like this:

private class RatingMouseListener extends MouseAdapter {
    private final int index;

    public RatingMouseListener(int index) {
        this.index = index;
    }

    @Override
    public void mouseEntered(MouseEvent e) {
        System.out.println("Mouse entered for rating " + index);
    }

    @Override
    public void mouseExited(MouseEvent e) {
        System.out.println("Mouse exited for rating " + index);
    }
}

Then, you just override any method in MouseAdapter.

Also, like other people said, you might want to use JButtons instead of JLabels because they have better support for action events. You can still give them icons.