Android - SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length

Digging into SPAN_EXCLUSIVE_EXCLUSIVE

SPAN_EXCLUSIVE_EXCLUSIVE in Android's Spannable world means excluding start and end indices from the fun. It's like the span throws a party on your text string, but refuses entry to characters inserted at its boundaries.

How to tame the error beast

Ever noticed this error with specific keyboards? Auto-suggestions or text prediction can play naughty and throw zero-length spans around:

1. Becoming friends with the default Android keyboard can save the day, or suggest your users to do so.
2. Put on the disguise of the inputType "textNoSuggestions" in your XML layout or if you prefer the coding way:

   // Asking politely EditText to refrain from auto-suggestions
   editText.setInputType(InputType.TYPE_TEXT_FLAG_NO_SUGGESTIONS);
   

3. Dealing with stubborn Samsung devices avatars of TouchWiz? Let's clean their keyboard cache now and then.
4. Embrace the vanilla flavor: devices with Stock Android offer better alignment with span rules.

What's hiding behind the curtains, aka LogCat

LogCat entries might look cryptic, but they hide treasures. Look for patterns that might point at third-party keyboards or specific Android versions as the culprits of zero-length nonsense.

Beware of your coding playground

Ensuring your SpannableStringBuilder has a strong base (read: correct implementation) is crucial for a smooth ride:

// Casting a "red" spell on "Hello"
SpannableStringBuilder ssb = new SpannableStringBuilder("Hello World");
ssb.setSpan(new ForegroundColorSpan(Color.RED), 0, 5, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);


No errors allowed zone

Building your app's text input strategy can control the reign of SPAN_EXCLUSIVE_EXCLUSIVE errors:

1. During code review, watch for span ranges that don't include zero as a guest.
2. During UX design, create interfaces that discourage zero-length spans.
3. While testing, act like different types of users to see if rapid typing or predictive text can trip you up.

Mastering text experiences

A robust text editing experience requires solid foundations. Consider custom components to deal with known issues with spans and keyboards:

1. Subclass TextView and boss around onTextChanged to sanitize input before applying spans.
2. Monitor for insertion points, and adjust spans programmatically to prevent zero-length issues.
3. Explore onDraw customization to manually handle text rendering if needed.