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On Clicking one button, it Triggers another button in recycle view

I'm currently working on a attandance management Android app. In my recyclerview there are list of student detail being populated dynamically from database. When i click the first button in the list, it also change the button colour of the 11th button of the list Like wise to 2nd button click changes the colour of 12th View button
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> {
Context context;`enter code here`
List<StudentDetails> MainImageUploadInfoList;
public RecyclerViewAdapter(Context context, List<StudentDetails> TempList) {
this.MainImageUploadInfoList = TempList;
this.context = context;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerview_items, parent, false);
ViewHolder viewHolder = new ViewHolder(view);
return viewHolder;
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
StudentDetails studentDetails = MainImageUploadInfoList.get(position);
holder.StudentNameTextView.setText(studentDetails.getName());
holder.StudentNumberTextView.setText(studentDetails.getPhoneNumber());
holder.st.setText(studentDetails.getRollno());
holder.cardView.setCardBackgroundColor(getcolor(position));
}
private int getcolor(int position) {
return Color.parseColor("#" + Integer.toHexString(ContextCompat.getColor(context, R.color.normal)));
}
#Override
public int getItemCount() {
return MainImageUploadInfoList.size();
}
class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public TextView StudentNameTextView;
public TextView StudentNumberTextView;
public TextView st;
DatabaseReference databaseReference;
String se,wh,su,d;
Button b;
CardView cardView;
public ViewHolder(View itemView) {
super(itemView);
itemView.setOnClickListener(this);
StudentNameTextView = (TextView) itemView.findViewById(R.id.ShowStudentNameTextView);
StudentNumberTextView = (TextView) itemView.findViewById(R.id.ShowStudentNumberTextView);
st = (TextView) itemView.findViewById(R.id.studentrollno);
cardView=itemView.findViewById(R.id.cardview1);
se=Teacher.getInstance().getSe();
wh=Teacher.getInstance().getWh();
su=Teacher.getInstance().getSu();
d=Teacher.getInstance().getD();
b=itemView.findViewById(R.id.button3);
itemView.findViewById(R.id.button3).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(final View view ) {
int position=getAdapterPosition();
String message = String.valueOf(position) ;
databaseReference= FirebaseDatabase.getInstance().getReference("attandance").child(wh).child(se).child(su).child(d).child(message);
databaseReference.setValue("p");
itemView.findViewById(R.id.button3).setBackgroundColor(Color.GREEN);
itemView.findViewById(R.id.button4).setEnabled(false);
itemView.findViewById(R.id.button3).setEnabled(false);
Toast.makeText( context,"position is "+String.valueOf(position), Toast.LENGTH_SHORT).show();
}
});
itemView.findViewById(R.id.button4).setOnClickListener( new View.OnClickListener() {
#Override
public void onClick(final View view ) {
int position=getAdapterPosition();
String message = String.valueOf(position) ;
databaseReference= FirebaseDatabase.getInstance().getReference("attandance").child(wh).child(se).child(su).child(d).child(message);
databaseReference.setValue("A");
itemView.findViewById(R.id.button4).setBackgroundColor(Color.RED);
itemView.findViewById(R.id.button3).setEnabled(false);
itemView.findViewById(R.id.button4).setEnabled(false);
}
});
}
#Override
public void onClick(View view) {
// int position=this.getAdapterPosition();
// Intent intent=new Intent(context,mark.class);
// String message = String.valueOf(position);
// intent.putExtra("attan",message);
// context.startActivity(intent);
// Intent intent = new Intent(context,mark.class);
//String message = String.valueOf(position) ;
//intent.putExtra("attan",message);
//context.startActivity(intent);
// Toast.makeText( context,"position is "+String.valueOf(position), Toast.LENGTH_SHORT).show();
}
}
}
}

How to solve position problem in adapter? Using firebase as the backend

I'm creating an app with firebase as a backend. I'm using same adapter for different activity, now it is working good but positions were mismatched for example: The output of position 0 shows in position 1 and for position 1 shows in position 2 and so on.. How to solve this problem, The problem with the positions of the output.
Adapter:
public class FrontlistAdapter extends FirebaseRecyclerAdapter<Gamedata, FrontlistAdapter.ViewHolder> {
private static final String TAG = "GameAdapter";
Context mContext;
int positions;
public FrontlistAdapter(#NonNull FirebaseRecyclerOptions<Gamedata> options, Context context) {
super(options);
mContext = context;
}
#Override
protected void onBindViewHolder(#NonNull ViewHolder holder, int position, #NonNull Gamedata model) {
holder.name.setText(model.getName());
holder.address.setText(model.getAddress());
//Picasso.get().load(model.getFrontcover()).into(holder.Frontcover);
Glide.with(mContext).load(model.getFrontcover()).into(holder.Frontcover);
positions = position; //<-- here I'm having positions but output shows different for each positions
}
#NonNull
#Override
public ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
View v = layoutInflater.inflate(R.layout.gamerow,parent,false);
ViewHolder viewHolder = new ViewHolder(v);
return viewHolder;
}
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
ImageView Frontcover;
TextView name;
TextView address;
View v;
public ViewHolder(#NonNull View itemView) {
super(itemView);
Frontcover = (ImageView)itemView.findViewById(R.id.frontcover);
name = (TextView)itemView.findViewById(R.id.frontname);
address=(TextView)itemView.findViewById(R.id.frontaddress);
v = itemView;
itemView.setClickable(true);
itemView.setOnClickListener((View.OnClickListener) this);
}
#Override
public void onClick(View v) {
String className = mContext.getClass().getSimpleName();
Intent intent = null;
switch (className) {
case "GameActivity":
intent = new Intent(mContext, Center_details.class);
intent.putExtra("User", getRef(positions).getKey());
break;
case "KidsActivity":
intent = new Intent(mContext,AllCenterDetails.class);
intent.putExtra("Kids",getRef(positions).getKey());
break;
}
mContext.startActivity(intent);
}
}
}

first what you have to do is create the interface like this
public interface ClickListner {
void onClick(View view, int position);
}
then in your activity create object of the interface like this and pass to the adapter along with your other data
ClickListner listener = ClickListner();
FrontlistAdapter customAdapter = new
FrontlistAdapter(AcceptedOrdersActivity.this,listener);
riderView.setAdapter(customAdapter);
copy this outside onCreate and intent in this
private ClickListner ClickListner() {
ClickListner listener = new ClickListner() {
#Override
public void onClick(View view, int position) {
int tag = (int) view.getTag();
if(tag == 0)
{
//Intent here
}
}
};
return listener;
}
now your adapter should be this one
public class FrontlistAdapter extends
RecyclerView.Adapter<FrontlistAdapter .DataObjectHolder>{
ClickListner listenr;
Context context;
public FrontlistAdapter (Context context,ClickListner listenr) {
this.context = context;
this.listenr = listenr;
}
public static class DataObjectHolder extends RecyclerView.ViewHolder {
Context context;
public DataObjectHolder(View itemView,ClickListner listenr) {
super(itemView);
this.listenr = listenr;
Frontcover = (ImageView)itemView.findViewById(R.id.frontcover);
name = (TextView)itemView.findViewById(R.id.frontname);
address=(TextView)itemView.findViewById(R.id.frontaddress);
v = itemView;
setOnClickListeners();
}
private void setOnClickListeners() {
`v.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
v.setTag(0);
listenr.onClick(v, getAdapterPosition());
}
});
}
}
#NonNull
#Override
public FrontlistAdapter.DataObjectHolder onCreateViewHolder(#NonNull ViewGroup parent,
int viewType) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.cell_orderdetail_list, parent, false);
FrontlistAdapter.DataObjectHolder dataObjectHolder = new
FrontlistAdapter.DataObjectHolder(view,listenr);
return dataObjectHolder;
}
#Override
public void onBindViewHolder(#NonNull FrontlistAdapter.DataObjectHolder holder, int
position) {
}
#Override
public int getItemCount() {
return options.size;
}
}

positions = position;
This is your problem. You're setting one global position for everything in the adapter.
Everywhere you are currently using position, you should instead be calling getBindingAdapterPosition() on the ViewHolder.

I'd like to implement a recycler view click event

I want to implement a recycler view click event. I intended to have an event when I clicked tvRoomNum. But error 'TextView.setOnClickListener(android.view.View$OnClickListener)' on a null object reference' occurs. So I notice that tvRoomNum is null object and attempt to use 'findViewById'. But the function is not recognized. How can I solve the problem?
public class RoomAdapter extends RecyclerView.Adapter<RoomAdapter.CustomViewHolder> {
private Context context;
private ArrayList<RoomData> rooms;
public ArrayList<StudnetInRoomData> students;
private LayoutInflater inflater;
private RoomData room;
View view;
public RoomAdapter(Context context, ArrayList<RoomData> rooms) {
this.context = context;
this.rooms = rooms;
this.inflater = LayoutInflater.from(context);
students = new ArrayList<>();
}
#Override
public CustomViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
view = inflater.inflate(R.layout.single_room, parent, false);
return new CustomViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull CustomViewHolder holder, int position) {
room = rooms.get(position);
holder.tvRoomNum.setText(String.valueOf(room.roomNum));
}
#Override
public int getItemCount() {
return rooms.size();
}
public class CustomViewHolder extends RecyclerView.ViewHolder {
public TextView tvRoomNum;
public CustomViewHolder(View itemView) {
super(itemView);
tvRoomNum.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View view) {
Intent intent = new Intent(view.getContext(), PlusStudentActivity.class);
intent.putExtra("studentList", room.students);
context.startActivity(intent);
}
});
}
}
}
The code below is the adapter of the recycler view that implements the recycler view. This is a dual recircular view structure.
public class FloorAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> implements OnFloorItemClickListener {
OnFloorItemClickListener listener;
static public ArrayList<FloorData> floors;
private Context context;
private LayoutInflater layoutInflater;
private OnItemClickListener mListener = null;
public FloorAdapter(ArrayList<FloorData> floors, Context context) {
this.floors = floors;
this.context = context;
this.layoutInflater = LayoutInflater.from(context);
}
public interface OnItemClickListener{
void onItemClick(View v, int pos);
}
public void setOnItemClickListener(OnItemClickListener listener) {
this.mListener = listener ;
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = layoutInflater.inflate(R.layout.signle_floor, parent, false);
return new GridViewHolder(view);
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
((GridViewHolder)holder).recyclerView.setAdapter(new RoomAdapter(context, floors.get(position).rooms));
((GridViewHolder)holder).recyclerView.setLayoutManager(new GridLayoutManager(context, 5));
((GridViewHolder)holder).recyclerView.setHasFixedSize(true);
((GridViewHolder)holder).tvFloorNum.setText(String.valueOf(floors.get(position).floorNum));
}
#Override
public int getItemCount() {
return floors.size();
}
#Override public void onItemClick(RecyclerView.ViewHolder holder, View view, int position) {
if(listener != null){
listener.onItemClick(holder,view,position);
}
}
#Override
public int getItemViewType(int position) {
return floors.get(position).id;
}
public class GridViewHolder extends RecyclerView.ViewHolder {
RecyclerView recyclerView;
TextView tvFloorNum;
Button btnPlusRoom;
public GridViewHolder(View itemView) {
super(itemView);
recyclerView = itemView.findViewById(R.id.rvRooms);
tvFloorNum = itemView.findViewById(R.id.tvFloorNum);
btnPlusRoom = (Button)itemView.findViewById(R.id.btnPlusRoom);
btnPlusRoom.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v)
{
int pos = getAdapterPosition();
if (pos != RecyclerView.NO_POSITION)
{
if(mListener != null){
mListener.onItemClick(v, pos);
}
}
}
});
}
}
}

Your TextView is null, because you are missing the findViewById():
You find the Id on a View, in this case, it is the itemView
The function was not recognised because you would've just called findViewById() & ViewHolder does not have that method,
You should've called itemView.findViewById() instead.
Try this:
public class CustomViewHolder extends RecyclerView.ViewHolder {
public TextView tvRoomNum;
public CustomViewHolder(View itemView) {
super(itemView);
tvRoomNum = itemView.findViewById(R.id.your_textview_id) // THIS
tvRoomNum.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View view) {
Intent intent = new Intent(view.getContext(), PlusStudentActivity.class);
intent.putExtra("studentList", room.students);
context.startActivity(intent);
}
});
}
}

How to add a recyclerview item dynamically when click a button in another activity?

I have a recyclerview in ShoppingCartActivity and a button in ProductDetailActivity. I want to send some data to ShoppingCartActivity when a button clicked in ProductDetailActivity and display them in recyclerview item that creates dynamically in ShoppingCartActivity.
I added addData method to recyclerview Adapter but it doesn't work and app crashes.
shop_btn = findViewById(R.id.add_to_shopping_cart);
shop_btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent addToCart = new Intent(ProductDetailActivity.this, ShoppingCartActivity.class);
startActivity(addToCart);
}
});
//HERE IS MY RECYCLERVIEW ADAPTER
public class RecyclerViewAdapter_ShoppingCart extends RecyclerView.Adapter<RecyclerViewAdapter_ShoppingCart.MyViewHolder> {
private Context context;
List<CartItems> cartItemsList;
public RecyclerViewAdapter_ShoppingCart(Context context, List<CartItems> cartItemsList) {
this.context = context;
this.cartItemsList = cartItemsList;
}
#NonNull
#Override
public MyViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view;
LayoutInflater layoutInflater = LayoutInflater.from(context);
view = layoutInflater.inflate(R.layout.card_cart, parent, false);
return new MyViewHolder(view);
}
#NonNull
#Override
public void onBindViewHolder(#NonNull final MyViewHolder holder, final int position) {
holder.cart_title.setText(cartItemsList.get(position).getTitle());
holder.cart_price.setText(cartItemsList.get(position).getPrice());
Picasso.get().load(cartItemsList.get(position).getImageUrl()).into(holder.cart_img);
}
#Override
public int getItemCount() {
return cartItemsList.size();
}
public static class MyViewHolder extends RecyclerView.ViewHolder {
TextView cart_title, cart_price;
ImageView cart_img;
public MyViewHolder(View itemView) {
super(itemView);
cart_title = itemView.findViewById(R.id.cart_title);
cart_price = itemView.findViewById(R.id.cart_price);
//cart_delete = itemView.findViewById(R.id.cart_delete);
cart_img = itemView.findViewById(R.id.cart_image);
}
}
public void addItem(List<CartItems> cartItems) {
CartItems newValue = new CartItems();
newValue.setTitle("123");
newValue.setPrice("123");
newValue.setImageUrl("");
cartItems.add(newValue);
notifyDataSetChanged();
}
}
My goal is adding recyclerview items dynamically to ShoppingCartActivity when a button clicked in ProductDetailActivity but app crashes.

viewHolder.getAdapterPosition() in adapter return -1 position and it caused IndexOutOfBoundException

i try to implement best practice to handle onclick in adapter, but i got problem IndexOutOfBoundException when getAdapterPostition inside onCreateViewHolder, whats wrong with my code?
i already try to check but not solve yet.
public class VideoAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private DataFrontVideo datas;
private Context context;
public VideoAdapter(DataFrontVideo datas, Context context) {
this.datas = datas;
this.context = context;
}
#NonNull
#Override
public RecyclerView.ViewHolder onCreateViewHolder(#NonNull ViewGroup viewGroup, int i) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.item_video,null);
final ViewHolder viewHolder = new ViewHolder(view);
view.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
DataVideo video = datas.getContent().get(viewHolder.getAdapterPosition()); // ERROR HERE
Intent intent = new Intent(context,DetailActivity.class);
intent.putExtra("datas",video);
context.startActivity(intent);
}
});
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull RecyclerView.ViewHolder viewHolder, int position) {
DataVideo dataVideo = datas.getContent().get(position);
ViewHolder vh = (ViewHolder)viewHolder;
vh.tvTitle.setText(dataVideo.getJudul());
vh.tvArtis.setText(dataVideo.getAlias());
vh.tvPrice.setText((dataVideo.getPrice().equals("0")?"Gratis":dataVideo.getPrice()));
Glide.with(vh.img.getContext()).load(dataVideo.getThumb_pic()).into(vh.img);
}
#Override
public int getItemCount() {
return (datas == null)? 0 : datas.getContent().size();
}
public class ViewHolder extends RecyclerView.ViewHolder{
private ImageView img;
private TextView tvTitle,tvArtis,tvPrice;
public ViewHolder(#NonNull View itemView) {
super(itemView);
img = itemView.findViewById(R.id.imgVideo);
tvArtis = itemView.findViewById(R.id.tvartis);
tvTitle = itemView.findViewById(R.id.tvTitle);
tvPrice = itemView.findViewById(R.id.tvPrice);
}
}
}
it should not return -1

Inside your ViewHolder you need to apply the setOnClickListener and get the item position on click by using the getAdapterPosition() like below
public class ViewHolder extends RecyclerView.ViewHolder{
private ImageView img;
private TextView tvTitle,tvArtis,tvPrice;
public ViewHolder(#NonNull View itemView) {
super(itemView);
img = itemView.findViewById(R.id.imgVideo);
tvArtis = itemView.findViewById(R.id.tvartis);
tvTitle = itemView.findViewById(R.id.tvTitle);
tvPrice = itemView.findViewById(R.id.tvPrice);
YOUR_VIEW.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Toast.makeText(mContext,"Position==>> "+getAdapterPosition(),Toast.LENGTH_LONG).show();
DataVideo video = datas.getContent().get(viewHolder.getAdapterPosition()); // ERROR HERE
Intent intent = new Intent(context,DetailActivity.class);
intent.putExtra("datas",video);
context.startActivity(intent);
}
});
}
}

Actually, the problem just because you are registering click listener in your onCreateViewHolder which is wrong you need to register on Click listener in your onBindViewHolder like bellow
#Override
public void onBindViewHolder(#NonNull RecyclerView.ViewHolder viewHolder, int position) {
DataVideo dataVideo = datas.getContent().get(position);
ViewHolder vh = (ViewHolder)viewHolder;
vh.tvTitle.setText(dataVideo.getJudul());
vh.tvArtis.setText(dataVideo.getAlias());
vh.tvPrice.setText((dataVideo.getPrice().equals("0")?"Gratis":dataVideo.getPrice()));
Glide.with(vh.img.getContext()).load(dataVideo.getThumb_pic()).into(vh.img);
vh.parentView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(context,DetailActivity.class);
intent.putExtra("datas",dataVideo);
context.startActivity(intent);
}
});
}

Move your click in onBindViewHolder .Here it will work for title click ,if you want all click make viewholder complete layout and implement click listener
#Override
public void onBindViewHolder(#NonNull RecyclerView.ViewHolder viewHolder, int position) {
DataVideo dataVideo = datas.getContent().get(position);
ViewHolder vh = (ViewHolder)viewHolder;
vh.tvTitle.setText(dataVideo.getJudul());
vh.tvArtis.setText(dataVideo.getAlias());
vh.tvPrice.setText((dataVideo.getPrice().equals("0")?"Gratis":dataVideo.getPrice()));
Glide.with(vh.img.getContext()).load(dataVideo.getThumb_pic()).into(vh.img);
vh.tvTitle.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(context,DetailActivity.class);
intent.putExtra("datas",dataVideo );
context.startActivity(intent);
}
});
}