Google keyboard mess up my custom span

Question

Well, I try to build a rich text editor. I have some buttons to format my editable text (bold, italic, URL, etc.).
I use Google keyboard with all text correction options enabled (Settings > Language & input > Google keyboard > Text correction).

I do the following:

In my EditText, I write some text.

I select it and apply a bold span with SPAN_EXCLUSIVE_EXCLUSIVE (33) as flags.

Then, I move my cursor to the end.

Finally, I add text to the end of the text. Added text should be without bold.

Okay, here is the problem. My bold span flags has changed... Why!?

Here is some logs:

D/ContentUtils: beforeTextChanged: start  end  span             flags
D/ContentUtils: beforeTextChanged: 0      7    ChangeWatcher    8388626
D/ContentUtils: beforeTextChanged: 0      7    ChangeWatcher    6553618
D/ContentUtils: beforeTextChanged: 0      7    TextKeyListener  18
D/ContentUtils: beforeTextChanged: 0      7    SpanController   18
D/ContentUtils: beforeTextChanged: 7      7    START            546
D/ContentUtils: beforeTextChanged: 7      7    END              34
D/ContentUtils: beforeTextChanged: 0      7    SpellCheckSpan   33
D/ContentUtils: beforeTextChanged: 0      7    CustomBoldSpan   33

D/ContentUtils: onTextChaghed
D/ContentUtils: onTextChaghed:     0      8    ChangeWatcher    8392722
D/ContentUtils: onTextChaghed:     0      8    ChangeWatcher    6557714
D/ContentUtils: onTextChaghed:     0      8    TextKeyListener  4114
D/ContentUtils: onTextChaghed:     0      8    SpanController   4114
D/ContentUtils: onTextChaghed:     8      8    START            546
D/ContentUtils: onTextChaghed:     8      8    END              34
D/ContentUtils: onTextChaghed:     0      8    CustomBoldSpan   4129
D/ContentUtils: onTextChaghed:     0      8    UnderlineSpan    289
D/ContentUtils: onTextChaghed:     0      8    ComposingText    289

D/ContentUtils: afterTextChanged
D/ContentUtils: afterTextChanged:  0      8    ChangeWatcher    8392722
D/ContentUtils: afterTextChanged:  0      8    ChangeWatcher    6557714
D/ContentUtils: afterTextChanged:  0      8    TextKeyListener  4114
D/ContentUtils: afterTextChanged:  0      8    SpanController   4114
D/ContentUtils: afterTextChanged:  8      8    START            546
D/ContentUtils: afterTextChanged:  8      8    END              34
D/ContentUtils: afterTextChanged:  0      8    CustomBoldSpan   4129
D/ContentUtils: afterTextChanged:  0      8    UnderlineSpan    289
D/ContentUtils: afterTextChanged:  0      8    ComposingText    289
D/ContentUtils: afterTextChanged:  0      8    SpellCheckSpan   33

When I use another keyboard, all went fine.
When I disabled Text correction settings, all went fine. All of my span are custom span and subclass an existing Android span.

It seems Google Keyboard modify my spans by its own (probably because of Show suggestions settings).
How can I avoid this?
Maybe I am missing something about span flags?

Answer 1

Ok, after some research, it seems the keyboard apply some spans around a word while typing in order to manage suggestions.

Problem is for each typed letter, the word is removed and added back with the added letter. At this point I loose some custom spans, like those in the middle of the word.

If you add a TextWatcher to your EditText, it will be called 2 times: first with the added letter, second after removed and added back the whole word. Not convenient at all.

So, an ugly solution is to copy all spans during beforeTextChanged() and apply back during the second afterTextChanged(). But it is complicated to implement.

Anyway, other apps do not do better: GMail and Evernote have same kind of issues. I choose to not worry and do not apply the ugly solution. My rich text editor is usable like this...