hello,I installed ubunutu16.04 on the TX2,but I could not use my typewriting one day,now,I can not find configured ibus or fcitx in the entry setting,help me please!thank you!

Not sure I understand correctly, but from Ubuntu GUI, in top bar on the right between network and sound icons, there should be an icon for language settings. Clicking on it you should see last option ‘Text Entry Settings’. Using this you will be able to add new lang with the ‘+’ button. With arrows you may up it till top position so that it becomes the default option for next sessions. You may have to select manually for testing before logging out (or rebooting).

This might be of interest (I haven’t set up anything like this myself):

Thank you !I may not describe it clearly,I have install ibus with sudo apt-get install ibus-pinyin,ibus-setup,but in the ‘Text Entry Setting’,when I clicked the "+"button,I only find chinese,and can not find chinese(pinyin).

I have no experience with this, but this may be of interest.
Maybe you’ll have to select Chinese, logout, then install ibus-m17n from Ubuntu Software Center, then logout and then you may be able to add and select pinyin.

ok!Thank you very much!