Java: Using a set of Enum values as a SpinnerListModel

Question

I apologize in advance if this has been asked elsewhere, but I have looked around and I can't seem to find an answer that fits my situation.

Some background: I have taken it upon myself to write a sort of "RPG character builder" for the Savage Worlds RPG system. I am using the NetBeans IDE to design a UI for this application. So far, things have gone pretty smoothly, but I am now encountering an error I can't seem to figure out.

I have a set of Attributes: Agility, Strength, Smarts, Spirit, and Vigor. The values for those attributes are a Die-type, ie d4, d6...d12. I created an Enum to represent these die types:

public enum DieType {

    D4(4), D6(6), D8(8), D10(10), D12(12);

    private int face;

    private DieType(int face) {
        this.face = face;
    }

    public int getValue() {
        return face;
    }

    @Override
    public String toString() {
        String dieType = "d" + face;
        return dieType;
    }

}

In my UI, I created a series of JSpinners to be able to adjust the values for each attribute. I wanted to use those die types in the spinners, so I initialized a new SpinnerListModel for them:

agiSpin.setModel(new SpinnerListModel(DieType.values()));

So far, so good, everything is still working well, and I can run the application and the window appears with the Enum list populated for each of the spinners. (Planning to move the model initialization to a variable that I can plug into each individual spinner, but right now I am working with NetBeans-generated code, so am creating each instance separately).

The problem occurs when I attempt to intialize a value for each spinner based on an instance of my SWCharacter class, instantiated before the GUI is drawn. For the above agiSpin spinner, I do as such: agiSpin.setValue(swchar.getAgiAttr()); in order to assign the appropriate value. The variable agiAttr is an instance of the DieType Enum. When I run the program, I get:

Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: invalid sequence element
at javax.swing.SpinnerListModel.setValue(SpinnerListModel.java:185)
at javax.swing.JSpinner.setValue(JSpinner.java:356)

...originating from that attempt to set the value.

What am I doing wrong with this? Do I need to create the List Model in a different way? Is there a syntax error in the way I'm attempting to assign values?

score 1 · Answer 1 · answered May 05 '14 at 18:56

1

A Spinner is usually used for integer or double values that the user inputs. In this case, I would use a ComboBox in which each value is initialized. The code to create a JComboBox would be:

    JComboBox die = new JComboBox<DieType>(DieType.values());

This should work. In NetBeans, it automatically creates the ComboBox, so you will need to right click and click "Customize Code" and make the necessary changes like above.

answered May 05 '14 at 18:56

user3574624

33
6

I thought about the ComboBox idea, but thought it would be better to have the spinner increment/decrement functionality. I was under the impression from the API that the SpinnerListModel was designed to handle more than just integer/double values...and as I said, the list works fine - it's just the problem with attempting to assign a specific value to it where the issue occurs. – amthomas2112 May 05 '14 at 20:06

score 0 · Answer 2 · answered May 05 '14 at 20:51

The answer to my problem was pretty much a derp on my part. I didn't properly initialize the default value I wanted the character attributes to have. Once I fixed that, the error no longer occurred, and the values in the spinners were assigned and displayed correctly.

For those who might be newer to Java and/or GUI design...

Right before the initialization of the spinner that was throwing the exception, I added a System.out.println(); for the two values in question:

agiSpin.setModel(new SpinnerListModel(DieType.values()));
//Check to see what value was being passed from the swchar Object
System.out.println(swchar.getAgiAttr()); 

//I wanted to see what the actual value was that was assigned to the Spinner when I initialized it with DieType.values()
System.out.println(agiSpin.getValue()); 
agiSpin.setValue(swchar.getAgiAttr());

I had thought I initialized the variable agiAttr as being DieType.D4, but the System.out.println() told me the truth: getAgiAttr() returned a value of null, and as such, agiSpin.getValue() was returning "d4", because that's the value it was being assigned by instantiating the spinner, not from the assignment I was attemping.

It was a noob error on my part, but hopefully my error will help others who might happen upon this question. Thank you to anyone who took the time to read/answer this.

Java: Using a set of Enum values as a SpinnerListModel

2 Answers2