在android编程中，如何将EditText中的特殊字转换为特殊颜色？

EditText editText = findViewById(R.id.editText);
String text = editText.getText().toString();
SpannableString spannableString = new SpannableString(text);

Pattern pattern = Pattern.compile("特殊字");
Matcher matcher = pattern.matcher(text);
while (matcher.find()) {
    int start = matcher.start();
    int end = matcher.end();
    ForegroundColorSpan colorSpan = new ForegroundColorSpan(Color.RED);
    spannableString.setSpan(colorSpan, start, end, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
}

editText.setText(spannableString);
editText.setSelection(text.length()); // 保持光标在文本末尾