1. Command line: sudo apt-get install fcitx-googlepinyin
2. System settings -> Language support -> Keyboard input method system, change to fcitx.
3. Log out log in
4. At top right, click the penguin icon -> Text entry setting
5. Click +
6. Search 'Google', find 'Google Pinyin (Fcitx)'
7, Use 'Ctrl+space' to switch between input methods
