This article explains how to subclass a list box in Symbian OS, especially in UIQ. One reason to subclass a list box is to have our own custom list box, for example you can display a double line list box (see Figure 1a). I will focus the discussion in this article on UIQ because Series 60 has already various types of list box, for instance CAknDoubleStyleListBox, CAknSingleHeadingStyleListBox, etc. In most cases, you can use one of these classes.

The most popular archive file format used these days is ZIP, originally created by Phil Katz from the modification of ARC format. Symbian OS provides a class, called CZipFile, to read ZIP file. This class is supported by Symbian since version 7.x. This article will show how to use CZipFile and give an example. You can compile and run the example in Series 60 2.x or UIQ 2.x.

If you have been reading discussions at Forum Nokia Developer Discussion Board recently, you may notice there are many questions about signing in S60 3rd Edition. It seems the new security feature in Symbian 9 has led to frustration for some developers. I would like to share what kind of error messages I have seen when installing signed/unsigned application in S60 3rd Edition phones. There is a hint that explains what may cause a particular message.

This article explains the Symbian OS executable file format (E32Image), including the header information and how the executable sections are organized. Note that this article is not based on the official specification from Symbian. They don't release the E32 specification file format and there is not so much information about it. Fortunately Symbian has released the source code of PETRAN that helps us to figure out E32 file format.

Symbian has released Symbian OS version 9. A lot of new features and changes have been introduced in this new version. One of them is the new executable file format (E32Image). This article discusses how the new format looks like. If you want to know about pre-Symbian OS 9 format, read my previous article.