Styjun

I am trying to search for the information in my firebase db, and I am not able to do so.

This is the class in which I'm searching from:

private FirebaseRecyclerAdapter<DjProfile, ResultsViewHolder> firebaseRecyclerAdapter;
 public static Query query;

 public static String searchData;
 DatabaseReference mProfileDatabase;
 @Override
 protected void onCreate(Bundle savedInstanceState) 
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_attendee_landing);
 Toolbar toolbar = findViewById(R.id.toolbar);
 setSupportActionBar(toolbar);


 final RecyclerView recyclerView = findViewById(R.id.results_recycler);
 recyclerView.setLayoutManager(new LinearLayoutManager(this));

 final EditText t = (EditText) findViewById(R.id.DjNameET);

 mProfileDatabase = FirebaseDatabase.getInstance().getReference();

 t.setOnEditorActionListener(new TextView.OnEditorActionListener() 
 @Override
 public boolean onEditorAction(TextView textView, int i, KeyEvent keyEvent) 
 if(i == EditorInfo.IME_ACTION_SEARCH)
 
 searchData = t.getText().toString();


 return true;
 
 return false;
 
 );

 ImageButton imgB= (ImageButton) findViewById(R.id.searchBtn);

 imgB.setOnClickListener(new View.OnClickListener()

 @Override
 public void onClick(View view)
 
 query = mProfileDatabase.orderByChild("djprofile")
 .startAt(searchData)
 .endAt(searchData + "uf8ff");


 
 );
 FirebaseRecyclerOptions<DjProfile> firebaseRecyclerOptions = new FirebaseRecyclerOptions.Builder<DjProfile>()
 .setQuery(query, DjProfile.class)
 .build();
 firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<DjProfile, ResultsViewHolder>(firebaseRecyclerOptions)
 

 @NonNull
 @Override
 public ResultsViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) 
 View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.searchitem_list, viewGroup, false);

 return new ResultsViewHolder(view);
 

 @Override
 protected void onBindViewHolder(@NonNull ResultsViewHolder holder, int position, @NonNull DjProfile model) 
 holder.setDjProfile(model);
 
 ;
 recyclerView.setAdapter(firebaseRecyclerAdapter);


 

 @Override
 protected void onStart()
 
 super.onStart();
 firebaseRecyclerAdapter.startListening();
 

Here is the exception I am getting: (says to be occuring in the onStart() method)

java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.firebase.database.ChildEventListener com.google.firebase.database.Query.addChildEventListener(com.google.firebase.database.ChildEventListener)' on a null object reference

Any help as to why this is null would be greatly appreciated!

To be able to initialize the adapter, you need to have a valid query. And to be able to create the query, you need to have the searchData. This means that the initialization of the firebaseRecyclerAdapter should happen inside the onClick.

imgB.setOnClickListener(new View.OnClickListener()

 @Override
 public void onClick(View view)
 
 query = mProfileDatabase.orderByChild("djprofile")
 .startAt(searchData)
 .endAt(searchData + "uf8ff");

 FirebaseRecyclerOptions<DjProfile> firebaseRecyclerOptions = new FirebaseRecyclerOptions.Builder<DjProfile>()
 .setQuery(query, DjProfile.class)
 .build();
 firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<DjProfile, ResultsViewHolder>(firebaseRecyclerOptions)
 

 @NonNull
 @Override
 public ResultsViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) 
 View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.searchitem_list, viewGroup, false);

 return new ResultsViewHolder(view);
 

 @Override
 protected void onBindViewHolder(@NonNull ResultsViewHolder holder, int position, @NonNull DjProfile model) 
 holder.setDjProfile(model);
 
 ;
 recyclerView.setAdapter(firebaseRecyclerAdapter);
 
);