AnkiDroid Flashcards released a big 2.15.0 update yesterday. This causes a problem reviewing cards in the Hanping deck. Luckily this can be easily fixed by adding a field to the Hanping note type.
Hanping Chinese:
Launch AnkiDroid
Tap top-right (3 vertical dots) icon to bring up the overflow menu
Tap Manage note types
Tap Hanping Chinese Type to edit Hanping Chinese's note type
Tap top-right + icon to add a new field to the note type
Type Jyutping and tap OK
Return to the main AnkiDroid screen and check the problem is fixed
Hanping Cantonese:
Launch AnkiDroid
Tap top-right (3 vertical dots) icon to bring up the overflow menu
Tap Manage note types
Tap Hanping Cantonese Type to edit Hanping Cantonese's note type
Tap top-right + icon to add a new field to the note type
Type Pinyin and tap OK
Return to the main AnkiDroid screen and check the problem is fixed
For those using Hanping Anki note types and card templates created several years ago, you may also get a similar error regarding a "Notes" field. In which case, please add that too.