BlackBerry rating bar - similar to AppWorld "stars" feature

The Android platform has a RatingBar widget. I believe there is a similar field for BlackBerry because BlackBerry AppWorld uses a rating bar. What field are they ar开发者_JAVA技巧e using for that?

I was browsing another question on StackOverflow and found a reference to a BlackBerry knowledge base article that includes sample code for a RatingField.

The corollary to an Android Widget on the BlackBerry is a Field. The BlackBerry Widget SDK is meant for doing web development specifically for BlackBerry devices. I've edited your question to reflect this.

The important aspect to know about BlackBerry development is that the operating system is not open-source. RIM has chosen to make some APIs available for app developers, but they have not opened up the entire platform. RIM is able to access the entire operating system when they write an app themselves - such as the Facebook or Twitter apps, but if you are writing an app as a third-party developer, you are limited to what has been exposed in their developer JDE.

AppWorld may well use a built-in field that does the rating stars, but, if it exists, that field is not available for third-party developers.

It is actually pretty common in the BlackBerry culture to write your own Field objects. There is a ButtonField in the JDE, for example. It works well if you want a button with text. But if you want to make a button that contains only an image, there is no built-in ImageButtonField to use, and you cannot set an image on a plain ButtonField. You have to write your own button field to handle this.