No default radio button selected (J2ME, Java)

Question

Currently working on a mobile app in J2ME and have questions with radio button answer options. Any suggestion on how to make it so that no default answer is selected? We've tried:

cg8.setSelectedIndex( -1, true ); But get an out of bounds exception error

and

setSelectedFlags( boolean[] ) with all false, but also get another error.

To get around this, we've also tried creating an invisible radio button and have that set as selected, but couldn't find a way to make an invisible radio button either.

Any thoughts or suggestions would be great appreciated!!

Answer 1

It sounds to me like the platform is enforcing an appropriate convention, although I must apologise for taking a purist standpoint here; this won't really answer your question.

Radio buttons are used when there are multiple exclusive choices, of which one must be made; it makes a certain amount of sense, therefore, for the user interface to ensure that something is always selected. Ideally, the initial selection in a radio group should always be a safe and sensible default.

Answer 2

As far as I know, the only way to not have any radio button pre-selected is to draw the control yourself. Re-implement a radio button list using a Canvas or a CustomItem.

It's a lot of work, unfortunately.

You should look into LWUIT as it may have an intermediary solution.

Answer 3

"Radio buttons are used when there are multiple exclusive choices, of which one must be made"

I disagree. Radio buttons simply allow one selection max. Take multiple choice tests like the SAT, you don't have to answer every question and sometimes it's best not to.

Answer 4

@QUICKRecipes: I disagree - to allow one selection max is the job of the "Select" input. Convention brought around by browsers has changed the interpretation of radio input to one that can accept a none-answer. RFC1866 states:

At all times, exactly one of the radio buttons in a set is checked. If none of the elements of a set of radio buttons specifies `CHECKED', then the user agent must check the first radio button of the set initially.

The whole nature of the original "real-life" radio button is that you one button must always be pressed. You canot "listen" to "null" radio station, and you cannot listen to multiple radio stations.