2.游標後新增字元

private void addChar(EditText editText, String data){
    int index = editText.getSelectionStart();
Editable editable = editText.getText();
editable.insert(index, data);
}

3.刪除游標前字元

private void deleteChar(EditText editText){
    int index = editText.getSelectionStart();
Editable editable = editText.getText();
 
editable.delete(index-1, index);
}