Develop Reference

Adding recyclerview

I would like to create a simple application which has two activities. Activity A has recyclerview, and Activity B uploads the input data of edittexts. Creating recyclerview and passing data work well, but the view is not created more than 1. I would like to know what did I do wrong.
Activity A which has recyclerview.
public class MainActivity extends AppCompatActivity {
private ArrayList<MainData> list;
private MainAdapter adapter;
private RecyclerView recyclerView;
private LinearLayoutManager linearLayoutManager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
recyclerView = (RecyclerView) findViewById(R.id.rv);
linearLayoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(linearLayoutManager);
list = (ArrayList<MainData>) getIntent().getSerializableExtra("list");
adapter = new MainAdapter(list);
recyclerView.setAdapter(adapter);
adapter.notifyDataSetChanged();
Activity B which uploads data.
public class upload extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_upload);
Button button = (Button) findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(upload.this, MainActivity.class);
ArrayList<MainData> list = new ArrayList<>();
EditText edit = (EditText) findViewById(R.id.edittext_name);
EditText edit_main = (EditText) findViewById(R.id.edittext_main);
list.add(new MainData(edit.getText().toString(), edit_main.getText().toString()));
intent.putExtra("list",list);
startActivity(intent);
finish();
}
});
Adapter :
public MainAdapter.CustomViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_list, parent, false);
CustomViewHolder holder = new CustomViewHolder(view);
return holder;
}
public void onBindViewHolder(#NonNull MainAdapter.CustomViewHolder holder, int position) {
//holder.iv_profile.setImageResource(list.get(position).getIv_profile());
holder.tv_name.setText(list.get(position).getTv_name());
holder.tv_content.setText(list.get(position).getTv_content());
holder.itemView.setTag(position);
#Override
public int getItemCount() {
return (null != list ? list.size() : 0);
}
public void remove(int position) {
try {
list.remove(position); //
notifyItemRemoved(position);
} catch (IndexOutOfBoundsException ex) {
ex.printStackTrace();
}
}
public class CustomViewHolder extends RecyclerView.ViewHolder {
protected ImageView iv_profile;
protected TextView tv_name;
protected TextView tv_content;
public CustomViewHolder(#NonNull View itemView) {
super(itemView);
this.iv_profile = (ImageView) itemView.findViewById(R.id.iv_profile);
this.tv_name = (TextView) itemView.findViewById(R.id.tv_name);
this.tv_content = (TextView) itemView.findViewById(R.id.tv_content);
}
}

About opening a new activity in respond to a click on a RecyclerView item which is inside of a fragment

I'm loading some data into a RecyclerView from Firebase Realtime Database. This RecyclerView is in a fragment and I want to open a new activity when an item is clicked. But when i add the onClickListener to an item from the adapter, my click doesn't even recognized by the app. I'm not sure what I'm doing wrong here because this method worked fine for a RecyclerView when it is inside of a normal activity.
This is a project for my university and I should submit it tomorrow. So I can really use some help.
This is the my data Adapter class,
public class Adapter_NoLimit extends RecyclerView.Adapter<Adapter_NoLimit.LViewHolder> {
Context context;
ArrayList<Helper> list_nl;
public Adapter_NoLimit(Context context, ArrayList<Helper> list_nl) {
this.context = context;
this.list_nl = list_nl;
}
#NonNull
#Override
public Adapter_NoLimit.LViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(context).inflate(R.layout.itemlist, parent, false);
return new LViewHolder(v);
}
#Override
public void onBindViewHolder(#NonNull Adapter_NoLimit.LViewHolder holder, int position) {
//final Helper temp = list_nl.get(position);
String fname_txt = list_nl.get(position).getFname();
String catg_txt = list_nl.get(position).getSpin();
String prof_img = list_nl.get(position).getProfile_url();
holder.setUsers(fname_txt, catg_txt, prof_img);
holder.f_name.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
AppCompatActivity activity = (AppCompatActivity) v.getContext();
Intent i = new Intent(activity, UserProfile_VV.class);
i.putExtra("full name", fname_txt);
activity.startActivity(i);
}
});
}
#Override
public int getItemCount() {
return list_nl.size();
}
public class LViewHolder extends RecyclerView.ViewHolder{
private TextView f_name, catG;
private ImageView profile_pic;
public LViewHolder(#NonNull View itemView) {
super(itemView);
f_name = itemView.findViewById(R.id.username_view);
catG = itemView.findViewById(R.id.category_view);
profile_pic = itemView.findViewById(R.id.userimage);
}
public void setUsers(String fname_txt, String catg_txt, String prof_img) {
f_name.setText(fname_txt);
catG.setText(catg_txt);
Picasso.get().load(prof_img).fit().into(profile_pic);
}
}
}
This is one of fragments,
public class Beauty_Frag extends Fragment {
RecyclerView recyclerView;
DatabaseReference reference, user_ref;
ArrayList<Helper> list;
Adapter adapter;
FirebaseAuth auth;
String uid;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.fragment_beauty, container, false);
recyclerView = v.findViewById(R.id.beauty_recycler_frag);
reference = FirebaseDatabase.getInstance().getReference();
user_ref = reference.child("users");
auth = FirebaseAuth.getInstance();
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
//searchField = findViewById(R.id.search_field);
list = new ArrayList<>();
adapter = new Adapter(getContext(), list);
recyclerView.setAdapter(adapter);
user_ref.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull /*#org.jetbrains.annotations.NotNull*/ DataSnapshot snapshot) {
for (DataSnapshot key : snapshot.getChildren()) {
if( key.child("spin").getValue().toString().equals("Beauty")) {
Helper helper = key.getValue(Helper.class);
list.add(helper);
adapter.notifyDataSetChanged();
}
}
}
#Override
public void onCancelled(#NonNull /*#org.jetbrains.annotations.NotNull*/ DatabaseError error) {
}
});
return v;
}
}
You are very welcome if you have any solution.

Use below code for onClicklistner:
holder.f_name.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent i = new Intent(context, UserProfile_VV.class);
i.putExtra("full name", fname_txt);
context.startActivity(i);
}
});

RecycerView always reset back to first position after inserting new Firebase data

My recyclerview always reset to first position after new data is inserted to firebase. In my TestAdapter class, I have an onClickListener which increments like on a post when clicked. Whenever I click on this "like" button, view is reset to first position. I believe this issue is related to setAdapter() being called on data changed. Please help!
MainActivity fetches "post" data from Firebase and populates it in TestAdapter class.
public class MainActivity extends AppCompatActivity {
private RecyclerView recyclerView;
private TestAdapter testAdapter;
private ArrayList<Post> postList;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
recyclerView = findViewById(R.id.recyclerView);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
fetchPostFromDB();
}
private void fetchPostFromDB() {
DatabaseReference databaseRef = FirebaseDatabase.getInstance().getReference("Post");
databaseRef.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot snapshot) {
postList = new ArrayList<>();
for (DataSnapshot snap : snapshot.getChildren()) {
String post = snap.child("post").getValue().toString();
Post post = new Post(post);
postList.add(post);
}
testAdapter = new TestAdapter(getApplicationContext(), postList);
recyclerView.setAdapter(testAdapter);
}
#Override
public void onCancelled(#NonNull DatabaseError error) {
}
});
}
TestAdapter binds the data (postList) and has an onClickListener.
public class TestAdapter extends RecyclerView.Adapter<TestAdapter.TestHolder> {
private List<Post> postList;
private Context context;
private DatabaseReference databaseReference;
public TestAdapter(Context ct, ArrayList<Post> postList) {
context = ct;
this.postList = postList;
}
#NonNull
#Override
public TestHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
LayoutInflater layoutInflater = LayoutInflater.from(context);
View view = layoutInflater.inflate(R.layout.post_item, parent, false);
final TestHolder holder = new TestHolder(view);
holder.ibLike.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String postID = postList.get(holder.getAdapterPosition()).getPostID();
databaseReference = FirebaseDatabase.getInstance().getReference("Posts").child(postID).child("likes");
int incrementLike = postList.get(holder.getAdapterPosition()).getLikes() + 1;
databaseReference.setValue(incrementLike);
}
});
return holder;
}
#Override
public void onBindViewHolder(#NonNull final TestHolder holder, final int position) {
holder.tvPost.setText(postList.get(position).getPost());
holder.tvVotes.setText(Integer.toString(postList.get(position).getLikes()));
}
#Override
public int getItemCount() {
return postList.size();
}
public static class TestHolder extends RecyclerView.ViewHolder {
TextView tvPost, tvLikes;
ImageButton ibLike;
public TestHolder(#NonNull View itemView) {
super(itemView);
tvPost = itemView.findViewById(R.id.tvPost);
tvLikes = itemView.findViewById(R.id.tvLikes);
ibLike = itemView.findViewById(R.id.ibLike);
}
}

Here need to initialize your adapter class from main activity. and then when data received just call adapter.notifiyDatasetChanged like:
onCreate():
postList = new ArrayList<>();
recyclerView = findViewById(R.id.recyclerView);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
testAdapter = new TestAdapter(getApplicationContext(), postList);
recyclerView.setAdapter(testAdapter);
and from your fetchPostFromDB delete adapter initialization insted of this just put this line testAdapter.notifiyDataSetChanged()
And when click on text button you can update/handle like this:
holder.ibLike.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String postID = postList.get(holder.getAdapterPosition()).getPostID();
databaseReference = FirebaseDatabase.getInstance().getReference("Posts").child(postID).child("likes");
int incrementLike = postList.get(holder.getAdapterPosition()).getLikes() + 1;
postList.get(holder.getAdapterPosition()).setLikes(incrementLike);
databaseReference.setValue(incrementLike);
notifyDataSetChanged();
}
});

Retrieving data from firebase to recyclerview does not work

As mentioned in the title, my recyclerview does not work. No idea why, because I do not get any errors or anything in the logcat or while building the app. Is there a way I could debug this or could you point out the mistake that I did?
I've implemented another recyclerview with the adapter, but I used a simple adapter. I tried using the firebaseUI in this case, and it seems that the adapter somehow cannot retrieve the data from the firebase firestore.
https://imgur.com/a/JSLXuou The screenshot of my database structure.
My adapter:
public class ManageAdapter extends FirestoreRecyclerAdapter<Manage, ManageAdapter.ManageHolder> {
public ManageAdapter(#NonNull FirestoreRecyclerOptions<Manage> options) {
super(options);
}
#Override
protected void onBindViewHolder(#NonNull ManageHolder holder, int position, #NonNull Manage model) {
holder.textviewName.setText(model.getName());
holder.textviewGrade.setText(model.getGrade());
//holder.textviewAge.setText(String.valueOf(model.getAge()));
}
#NonNull
#Override
public ManageHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.manage_item,
parent,false);
return new ManageHolder(v);
}
class ManageHolder extends RecyclerView.ViewHolder{
TextView textviewName;
TextView textviewAge;
TextView textviewGrade;
public ManageHolder(#NonNull View itemView) {
super(itemView);
textviewAge = itemView.findViewById(R.id.manage_item_title_age);
textviewGrade = itemView.findViewById(R.id.manage_item_grade);
textviewName = itemView.findViewById(R.id.manage_item_name);
}
}
}
Main class:
private FirebaseFirestore firebaseFirestore;
private Toolbar mToolbar;
private Button delete_event;
private RecyclerView participants;
private TextView manage_events_title;
private TextView participans_text;
private ManageAdapter adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_manage_events);
final String ID = getIntent().getExtras().getString("ID");
firebaseFirestore = FirebaseFirestore.getInstance();
delete_event = (Button) findViewById(R.id.delete_event);
manage_events_title = (TextView) findViewById(R.id.manage_events_title);
participans_text = (TextView) findViewById(R.id.participants_text);
participants = (RecyclerView) findViewById(R.id.recyclerview_manage);
setUpRecyclerView();
}
private void setUpRecyclerView(){
final String ID = getIntent().getExtras().getString("ID");
Query query = firebaseFirestore.collection("Events").document(ID).collection("Users");
FirestoreRecyclerOptions<Manage> options = new FirestoreRecyclerOptions.Builder<Manage>()
.setQuery(query, Manage.class).build();
adapter = new ManageAdapter(options);
participants.setHasFixedSize(true);
participants.setLayoutManager(new LinearLayoutManager(this));
participants.setAdapter(adapter);
}
#Override
protected void onStart() {
super.onStart();
adapter.startListening();
}
#Override
protected void onStop() {
super.onStop();
adapter.stopListening();
}
}

How to load firebase data into recyclerview

I'm seeking help on how to load a data stored in a Firebase Database into a recyclerview.
The below screenshot indicates how I would like for the data to be structured when loaded into the recyclerview.
I am able to access the data from individual paths such as "Upcoming/Events/03/23" using the addEventListener but unable to load dynamically into a recyclerview in the format above.
See Code below that I have below to load the children under the different nodes, but i'm able to load it into the recyclerview
private ListView mUserList;
private ArrayList<String> mUpcomingList = new ArrayList<>();
final ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this,android.R.layout.simple_expandable_list_item_1,mUpcomingList);
mUserList.setAdapter(arrayAdapter);
String CurrentString = date.toString().trim();
StringTokenizer tokens = new StringTokenizer(CurrentString, "/");
String first = tokens.nextToken();
String second = tokens.nextToken();
mDatabase = FirebaseDatabase.getInstance().getReference().child("Upcoming/Events").child(first);
mDatabase.addValueEventListener(new ValueEventListener() {
#Override
Public void onDataChange(DataSnapshot dataSnapshot) {
Log.d(TAG,"Listing children");
for (DataSnapshot child: dataSnapshot.getChildren()) {
mUpcomingList.add(child.getKey());
arrayAdapter.notifyDataSetChanged();
}
Your help is appreciated.

when you used then you make recyclerview adatper and bind this adapter into a recycler view . used below code for display firebase all the data and change according your need and make changes.
RecyclerView Adapter::
public class DisplayAllData extends RecyclerView.Adapter<DisplayAllData.ItemViewHolder>{
private List<User> mUserLsit=new ArrayList<>();
private Context mContext;
#Override
public ItemViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view= LayoutInflater.from(parent.getContext()).inflate(R.layout.row_layout,parent,false);
return new ItemViewHolder(view);
}
public DisplayAllData(Context mContext,List<User> mUserLsit) {
this.mContext=mContext;
this.mUserLsit = mUserLsit;
}
#Override
public void onBindViewHolder(ItemViewHolder holder, int position) {
User user=mUserLsit.get(position);
holder.mTvName.setText(user.name);
holder.mTvEmail.setText(user.email);
holder.mTvPwd.setText(user.pwd);
}
#Override
public int getItemCount() {
return mUserLsit.size();
}
public class ItemViewHolder extends RecyclerView.ViewHolder {
TextView mTvName,mTvEmail,mTvPwd;
public ItemViewHolder(View itemView) {
super(itemView);
mTvEmail=itemView.findViewById(R.id.rlTvEmail);
mTvName=itemView.findViewById(R.id.rlTvName);
mTvPwd=itemView.findViewById(R.id.rlTvPwd);
}
}
}
In Adapter take a simple layout and make three textview control and bind data into that.
then after take activity layout and define recycler view in xml. then after used below code to read firebase database record and display recyclerview.
public class DisplayActivity extends AppCompatActivity {
private RecyclerView mRvData;
private DisplayAllData allDataAdapter;
private DatabaseReference mDatabase;
private TextView mTvEmpty;
private FirebaseDatabase mFirebaseInstance;
private List<User> mUserList = new ArrayList<>();
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.display_data);
initView();
}
private void initView() {
mFirebaseInstance = FirebaseDatabase.getInstance();
mDatabase = mFirebaseInstance.getReference("usersDb/UserTable");
mRvData = findViewById(R.id.rvData);
mTvEmpty = findViewById(R.id.dlTvEmpty);
mRvData.setLayoutManager(new LinearLayoutManager(this));
mDatabase.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
mUserList.clear();
for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
User user = dataSnapshot1.getValue(User.class);
mUserList.add(user);
}
allDataAdapter = new DisplayAllData(DisplayActivity.this, mUserList);
mRvData.setAdapter(allDataAdapter);
allDataAdapter.notifyDataSetChanged();
if (mUserList.isEmpty())
mTvEmpty.setVisibility(View.VISIBLE);
else
mTvEmpty.setVisibility(View.GONE);
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
}

You have to use FirebaseRecyclerAdapter,
as
FirebaseRecyclerAdapter<Model, ViewHolder> Adapter = new FirebaseRecyclerAdapter<Model, ViewHolder>(
Model.class, //Name of model class
R.layout.row, //Row layout to show data
viewHolder.class, //Name of viewholder class
mDatabaseRef // Database Refernce
) {
#Override
protected void populateViewHolder(VieHolder viewHolder, Model model, int position) {
//Your Method to load Data
}
};
RecyclerView.setAdapter(Adapter);
For this you have to create two other classes, One is viewholder ( to display data) and second model class ( refers to name of nodes from where you are fetching data ).

final DatabaseReference cartListRef = FirebaseDatabase.getInstance().getReference().child("Cart List");
FirebaseRecyclerOptions<Cart> options = new FirebaseRecyclerOptions.Builder<Cart>()
.setQuery(cartListRef.child("User View")
.child(Prevalent.currentOnlineUser.getPhoneNumber())
.child("Products"), Cart.class).build();
FirebaseRecyclerAdapter<Cart, CartViewHolder> adapter =
new FirebaseRecyclerAdapter<Cart, CartViewHolder>(options) {
#Override
protected void onBindViewHolder(#NonNull CartViewHolder holder, int position, #NonNull final Cart model) {
holder.txtProductQuantity.setText("Quantity = " + model.getQuantity());
holder.txtProductName.setText(model.getPname());
holder.txtProductPrice.setText("Price = " + model.getPrice() + "৳");
int oneTypeProductPrice = ((Integer.valueOf(model.getPrice()))) * Integer.valueOf(model.getQuantity());
overTotalPrices = overTotalPrices + oneTypeProductPrice;
holder.itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
CharSequence options[] = new CharSequence[]
{
"Edit",
"Remove"
};
AlertDialog.Builder builder = new AlertDialog.Builder(CartActivity.this);
builder.setTitle("Cart Options");
builder.setItems(options, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int i) {
if (i == 0){
Intent intent = new Intent(CartActivity.this, ProductDetailsActivity.class);
intent.putExtra("pid", model.getPid());
startActivity(intent);
}
if (i == 1){
cartListRef.child("User View")
.child(Prevalent.currentOnlineUser.getPhoneNumber())
.child("Products")
.child(model.getPid())
.removeValue()
.addOnCompleteListener(new OnCompleteListener<Void>() {
#Override
public void onComplete(#NonNull Task<Void> task) {
if (task.isSuccessful()){
Toast.makeText(CartActivity.this,"Item removed successfully.",Toast.LENGTH_LONG).show();
Intent intent = new Intent(CartActivity.this, HomeActivity.class);
startActivity(intent);
}
}
});
}
}
});
builder.show();
}
});
}
#NonNull
#Override
public CartViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.cart_items_layout, parent, false);
CartViewHolder holder = new CartViewHolder(view);
return holder;
}
};
recyclerView.setAdapter(adapter);
adapter.startListening();
}