Question

This is driving me nuts!
I used both concatenation and format and while the strings produced match the correct paths, the loop throws exceptions from the get go.

what’s going on?

ImageIcon thisWorks= new ImageIcon(testview.class.getResource("/led_images/"+1+"_off.png"));
    for(int i = 1; i <= 10; i++)
    {
        String on = String.format("/led_images/%d_on.png",i);
        String off = String.format("/led_images/%d_off.png",i);


    ledIcons.put( i+"_off", new ImageIcon(testview.class.getResource(off)));
    ledIcons.put( i+"_on", new ImageIcon(testview.class.getResource(on)));
    }

Edit:
am I using Map incorrectly?
It’s a Map<String,ImageIcon> one.

Edit2:
Yeah I guess I’m using the map incorrectly.

I have it declared like this:

public Map< String, ImageIcon> ledIcons;

It’s a null value inside the loop.
So I guess it’s not like c++ then?

Edit3:
Yeah, nevermind this question, I didn’t initialize the field properly, my apologies.

Answer 1

Initialize the field:

public Map< String, ImageIcon> ledIcons = new HashMap< String, ImageIcon>();