I decided to use KWrite as my text editor finally. I'd been using gedit until yesterday. However, I suddenly couldn't open some files this morning. But they can be opened by vim. Then I try to find another editor like Notepad++ on Windows. In fact, I need the text encoding feature because I usually view and edit text files encoded as GBK and Shift_JIS.
Notepadqq is a good alternative to Notepad++ but unluckily my Chinese IME doesn't work in it. 😑
Finally I decided to use KWrite.