This repository contains an app demonstrating a IndexOutOfBoundsException when using multiple TextWatchers added to the same TextView and one removes itself.

This is the internal source code for the sendOnTextChanged method present in the TextView class:

void sendOnTextChanged(CharSequence text, int start, int before, int after) {
    if (mListeners != null) {
        final ArrayList<TextWatcher> list = mListeners;
        final int count = list.size();
        for (int i = 0; i < count; i++) {
            list.get(i).onTextChanged(text, start, before, after);
        }
    }

    if (mEditor != null) mEditor.sendOnTextChanged(start, before, after);
}

As we can see, when the text changes the code iterates over the list of listeners and notifies each one of them. The size of the list is used as the control variable of the for loop and is obtained at the beginning of the method.

final int count = list.size();

The problem happens when the TextWatcher removes itself (or any other TextWatcher) in the onTextChanged method. This modifies the inital size of the list generating a IndexOutOfBoundsException.