This is a feature of Windows and OS X.
And I'm sure many people will find it useful.

So I want to know is it possible to rename a file by single-click the file name?

I already know pressing F2 can do the job, I am just curious how to implement it by clicking the file name.
(I learned that this feature is available in KDE 3.x but I'm using KDE 4.x)


Moreover, when renaming a file, pressing tab key to rename next file is also very useful. So how to implement it?

Are you referring to Dolphin, or the Plasma Folder View?

Most likely dolphin (though I would guess that plasma folder view ought to be consistent). Afaik this functionality is not currently available (unless it was implemented in 4.6 or later, but I don't remember seeing anything about it). You are certainly welcome to submit a request to Brainstorm to add this functionality.

Thanks for sharing this idea. I think that this is more or less what this wish is about:

https://bugs.kde.org/show_bug.cgi?id=205157