Multiple choice dialog wont let me alter an array when clicked

Question

Hi I have a multiplechoice dialog on my activity. I have a boolean array to keep track of which items are selected from the dialog. So I want each time an item is clicked to make the corresponding place on my array true. The array is being created in the onCreateDialog before the return.

public Dialog onCreateDialog(int id) {
  userlistlocal=getuserlist(username);
  boolean[] usernamechecked=new boolean[userlistlocal.length/3];
  Arrays.fill(usernamechecked,false);         
  return new AlertDialog.Builder(Newevent.this)
        .setIcon(R.drawable.ic_menu_invite)
        .setTitle("Add People")
        .setMultiChoiceItems(userselectionlistlocal,
                null,new DialogInterface.OnMultiChoiceClickListener() {


                    public void onClick(DialogInterface dialog, int whichButton,
                            boolean isChecked) { 

                        /* User clicked on a check box do some stuff */
                     usernamechecked[whichButton]=isChecked;<-------HERE
                    }
                })
        .setPositiveButton("Ok", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int whichButton) {

                /* User clicked Yes so do some stuff */
            }
        })
        .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int whichButton) {

                /* User clicked No so do some stuff */
            }
        })
       .create();

 }

But when I put in the onClick method my boolean array it says it has to be final(Cannot refer to a non-final variable usernamechecked inside an inner class defined in a different method). I dont know what to do

Answer 1

You cannot access your array if it is not declared final. But if it is declared final you have to consider, that you can't modificate it anymore.

A method to resolve this problem is to define the OnMultiChoiceClickListener not as an anonymous inner class. For example you could define it as a inner class in the same class or even as a separate class.

Answer 2

you defined usernamechecked inside the onCreateDialog method, it only exists inside the scope of this method. You should define it as a member of your activity class or of the inner class. Since its size is dependent on a call to getuserlist, which i assume is a method of your activity class, i would add it as a member of your activity class although this is up to you.

Define usernamechecked as a member of your activity class as:

private boolean usernamechecked[];

I'd also move

userlistlocal=getuserlist(username);
usernamechecked=new boolean[userlistlocal.length/3];
Arrays.fill(usernamechecked,false); 

to your onCreate Method (or some other initialization method) if possible as it looks like it has nothing to do with the dialog creation but this is just a style / maintainability issue.