Fcitx5 for Android

Fcitx5 for Android is a keyboard for languages that a plain alphabet keyboard cannot handle. Chinese comes built in (Pinyin, Shuangpin, Wubi, Cangjie and your own custom tables), along with English and its spell check. Japanese, Korean, Vietnamese, Thai, Sinhala, Jyutping, Zhuyin and RIME schemas are each added by installing a small plugin.

It is the Linux Fcitx5 input engine ported to Android, so typing works the way it does on a desktop. You get an expandable candidate list, an emoji and symbol picker, a clipboard history for plain text, long-press popups for extra symbols, custom colour themes with a background image, and Android 12 dynamic colour. Plug in a physical keyboard and the candidate panel floats above your text.

The on-screen key layout cannot be rearranged yet. Also note that the Google Play build is signed with a different key from the F-Droid and GitHub builds, so you cannot update from one to the other without uninstalling first.