title: Detect have a zero length
body: <pre><code>public class c_Fragment_Chat extends Fragment {
  
  private RecyclerView recyclerView;
  private UserAdapter userAdapter;
  private List&lt;User&gt; mUsers;
  
  EditText s_search_student;
  
  @Override
  public View onCreateView(LayoutInflater inflater, ViewGroup container,
                           Bundle savedInstanceState) {
      // Inflate the layout for this fragment
      View view = inflater.inflate(R.layout.c_fragment_chat, container, false);
  
      recyclerView = view.findViewById(R.id.c_recycler_view);
      recyclerView.setHasFixedSize(true);
      recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
  
      mUsers = new ArrayList&lt;&gt;();
  
      readUsers();
  
      s_search_student = view.findViewById(R.id.s_search_student);
      s_search_student.addTextChangedListener(new TextWatcher() {
          @Override
          public void beforeTextChanged(CharSequence charSequence, int start, int count, int after) {
  
          }
  
          @Override
          public void onTextChanged(CharSequence charSequence, int start, int before, int count) {
  
              searchUsers(charSequence.toString().toLowerCase());
          }
  
          @Override
          public void afterTextChanged(Editable editable) {
  
          }
      });
  
      return view;
  }
  
  private void searchUsers(String s) {
  
      Query query = FirebaseDatabase.getInstance().getReference("User").orderByChild("search")
              .startAt(s)
              .endAt(s+"\uf8ff");
  
      query.addValueEventListener(new ValueEventListener() {
          @Override
          public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
  
              if(s_search_student.getText().toString().equals("")){
  
                  mUsers.clear();
  
                  for(DataSnapshot snapshot : dataSnapshot.getChildren()){
  
                      User user = snapshot.getValue(User.class);
                      mUsers.add(user);
                  }
  
                  userAdapter = new UserAdapter(getContext(), mUsers, false);
                  recyclerView.setAdapter(userAdapter);
              }
          }
  
          @Override
          public void onCancelled(@NonNull DatabaseError databaseError) {
  
          }
      });
  
  
  }
  
  private void readUsers() {
      DatabaseReference reference = FirebaseDatabase.getInstance().getReference("User");
  
      reference.addValueEventListener(new ValueEventListener() {
          @Override
          public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
  
              mUsers.clear();
              for(DataSnapshot snapshot : dataSnapshot.getChildren()){
                  User user = snapshot.getValue(User.class);
  
                      mUsers.add(user);
  
              }
  
              userAdapter = new UserAdapter(getContext(), mUsers, false);
              recyclerView.setAdapter(userAdapter);
          }
  
          @Override
          public void onCancelled(@NonNull DatabaseError databaseError) {
  
          }
      });
  }
  
  
  }
  </code></pre>
  
  <p>E/SpannableStringBuilder: SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero-length</p>
  
  <p>I don't know why my edit text can't able to detect the data changed from the string. Please give me a hand~ thank you very much. And the above is the error problem that I get.</p>