Apps how to select item in alert dialog

[skyaiee]

Hi,
I've seen several examples online showing an alert dialog with radio button options combined with regular buttons like this:

I want to do something very similar with two radio button options: Rider, Driver and a "Continue" and "Cancel" Button. This is my code:

final String roles[] = {"Rider","Driver"};

AlertDialog.Builder identifyRole=new AlertDialog.Builder(MainMenu.this);
identifyRole.setTitle("Are you a ...");
identifyRole.setSingleChoiceItems(roles, 0,new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
if (whichButton ==0){
// Rider is selected
}
else{
//Driver is selected
}
}
})
.setPositiveButton("Continue", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
// depending on whether Rider/Driver selected, launch new activity
// how do you tell whether rider/driver is selected???
}
})
.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {

}
});
identifyRole.show();
}

What I can't seem to figure out from the online tutorials is how to tell which item (Rider/Driver) is selected when I click on "Continue"? I know "whichButton" will tell me that value in the OnClick method in the setSingleChoiceItems, but I don't think that value carries over into the .setPostiveButton OnClick method. It's probably a simple answer, but I've been stuck on it for a few days now. Would appreciate help! Thanks!