Here is the instructions how to setup Chinese input method in Ubuntu Artful.
First, go to “Language Support”, make sure the “Chinese(simplified)” or “Chinese Traditional”(or both) is installed completely.
Go to “Input Method”, make sure you select “ibus” as the selected user configuration. An user logout may be required.
Go to “Settings -> Region & Language”, in the “Input Sources” section, add the “Chinese(Pinyin)” input method.
Now you should be able to see the input method icon “en/拼” on the top left corner of the desktop. Use “Super + Space” to switch the input method as normal.
Here is what the Ubuntu 17.10 desktop looks like.