Develop Reference

Removing element from adapter throws Index out of bound exception

I have two recycler views. The first recyclerview is basically a list of data where I can choose an item and its quantity and I am storing this chosen item data into a map. The second one is the list of the selected data. which I am generating from getting the values() from the map. The second one also has similar viewholder and I can change the quantity there also. One the quantity reaches zero I remove the item from the list and try to notifydatasetChanged().
The problem is the removing of an item from the second list is not working properly and the app crashes with error
java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter positionViewHolder
I am using a listener interface on my first Recycler so that when the quantity is changed and the item is added to the map. The adapter of the second recycler is notified of the changes. below is the code i am using to update the second recycler view.
public void updateList(){
mMap = ((UserMainActivity)getActivity()).getItemMap();
inputs.clear();
// adapter.notifyDataSetChanged();
adapter = new MyCartAdapter(inputs,getContext());
cartList.setAdapter(adapter);
for(AllItems t:mMap.values()) {
inputs.add(t);
}
adapter.notifyDataSetChanged();
}
Below is my second recycler view's adapter. Where I am changing the quantities of the selected items.
public class MyCartAdapter extends RecyclerView.Adapter<MyCartAdapter.MyCartViewHolder>{
private List<AllItems> listItems1;
private Context context;
private Typeface typeface;
public MyCartAdapter(List<AllItems> listItems1, Context context) {
this.listItems1 = listItems1;
this.context = context;
}
#NonNull
#Override
public MyCartAdapter.MyCartViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.cart_items_layout, parent, false);
return new MyCartViewHolder(v);
}
#Override
public void onBindViewHolder(#NonNull final MyCartAdapter.MyCartViewHolder holder, final int position) {
final AllItems orderItem = listItems1.get(position);
holder.setProductImage(orderItem.getImageUrl(),context);
holder.name.setText(orderItem.getName());
String price = String.valueOf(orderItem.getPrice());
holder.price.setText(price);
final HashMap<String, AllItems> items = ((UserMainActivity)context).getItemMap();
holder.counter.setText(orderItem.getQuantity());
holder.add.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String quantity = String.valueOf(holder.counter.getText());
int count = Integer.parseInt(quantity)+1;
holder.counter.setText(String.valueOf(count));
String url = orderItem.getImageUrl();
AllItems newitem = new AllItems(orderItem.getName(),orderItem.getComname(),url, String.valueOf(count),orderItem.getWeight,orderItem.getPrice());
((UserMainActivity)context).addItem(orderitemname,newitem);
// notifyItemChanged(position);
}
});
//counter text iitem.textview showing the quantity of the selected item . integer count returns the value of counter text below i am checking if its zero than it simply sets the value to zero and else reduce it and update the map.
holder.minus.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String counterText = String.valueOf(holder.counter.getText());
int count = Integer.parseInt(counterText);
if (count==0){
holder.counter.setText("0");
}
if (count==1){
holder.counter.setText("0");
AllItems item = items.get(orderItem.getName());
if (item!=null){
String orderit = orderItem.getName();
((UserMainActivity)context).removeItem(orderit);
// here i am removing the value from the list which throws the exception
listItems1.remove(position);
notifyItemRemoved(position);
}
}
if (count>1){
String quantity = String.valueOf(count-1);
holder.counter.setText(quantity);
String orderitemname = orderItem.getName();
String url = orderItem.getImageUrl();
String weight = "100";
long weightl = Long.parseLong(weight);
AllItems newitem = new AllItems(orderItem.getName(),orderItem.getComname(),url, quantity,weight,orderItem.getPrice());
((UserMainActivity)context).addItem(orderitemname,newitem);
// listItems1.set(position, newitem);
// notifyItemChanged(position);
}
}
});
}
#Override
public int getItemCount() {
return listItems1.size();
}
public class MyCartViewHolder extends RecyclerView.ViewHolder {
public TextView name,price,count,comname;
public TextView weight;
LinearLayout add,minus;
TextView counter;
public MyCartViewHolder(View itemView) {
super(itemView);
name = (TextView) itemView.findViewById(R.id.ProName);
price = (TextView) itemView.findViewById(R.id.proPrice);
weight = (TextView) itemView.findViewById(R.id.ProWeight);
counter = (TextView) itemView.findViewById(R.id.counter);
add = (LinearLayout) itemView.findViewById(R.id.addLin);
minus= (LinearLayout) itemView.findViewById(R.id.minusLin);
}
public void setProductImage(final String thumb_image, final Context ctx){
productImage = (ImageView) itemView.findViewById(R.id.ProImage);
Picasso.with(ctx).setIndicatorsEnabled(false);
Picasso.with(ctx)
.load(thumb_image)
.networkPolicy(NetworkPolicy.OFFLINE)
.placeholder(R.drawable.basket_b).into(productImage, new Callback() {
#Override
public void onSuccess() {
}
#Override
public void onError() {
Picasso.with(ctx).load(thumb_image).placeholder(R.drawable.basket).into(productImage);
}
});
}
public void setComname(String name){
comname = (TextView)itemView.findViewById(R.id.proComName);
comname.setText(name);
}
}
}

This jumps out at me:
listItems1.remove(position);
notifyItemChanged(position);
The notifyItemChanged() method exists to tell the adapter that the data at the given position has changed, and that the ViewHolder should be re-bound. This is not what you're doing; you're removing an item.
Probably your app is crashing because you're removing the last item in your data set (e.g. position 10) and then telling the adapter that the item at position 10 has changed... but now the maximum position in your data set is 9.
Instead, you should use the notifyItemRemoved() method.
listItems1.remove(position);
notifyItemRemoved(position);

How to set the position of each cardview inside a recyclerview?

I am making an application that takes all users of a table in Firebase and shows them in CardView, but I would like administrators to appear before the other users.
For this differentiation, all users were saved to the system with an attribute called type which says whether they are normal users or administrators.
This is TelaChat.java file:
public class TelaChat extends AppCompatActivity {
private RecyclerView recyclerView;
private DatabaseReference databaseReference;
private FirebaseRecyclerOptions<Usuario> options;
private FirebaseRecyclerAdapter<Usuario, ChatAdapter> adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_chat);
setTitle("Tela de Chat");
recyclerView = findViewById(R.id.cm_rv_membros);
recyclerView.setHasFixedSize(true);
databaseReference = FirebaseDatabase.getInstance().getReference().child("usuario");
options = new FirebaseRecyclerOptions.Builder<Usuario>().setQuery(databaseReference, Usuario.class).build();
adapter = new FirebaseRecyclerAdapter<Usuario, ChatAdapter>(options) {
#Override
protected void onBindViewHolder(ChatAdapter holder, int position, Usuario model) {
Picasso.with(holder.ivFoto.getContext()).load(model.getImageURL()).centerCrop().resize(140, 140).transform(new ImageTrans_CircleTransform2()).into(holder.ivFoto);
holder.tvNome.setText(model.getNome());
holder.tvTipo.setText(model.getTipo());
}
#Override
public ChatAdapter onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.chat_card, parent, false);
return new ChatAdapter(view);
}
};
GridLayoutManager gridLayoutManager = new GridLayoutManager(getApplicationContext(), 1);
recyclerView.setLayoutManager(gridLayoutManager);
adapter.startListening();
recyclerView.setAdapter(adapter);
}
This is ChatAdapter.java file:
public class ChatAdapter extends RecyclerView.ViewHolder{
public ImageView ivFoto;
public TextView tvNome;
public TextView tvTipo;
public ChatAdapter(View itemView) {
super(itemView);
ivFoto = itemView.findViewById(R.id.cc_iv_foto);
tvNome = itemView.findViewById(R.id.cc_tv_nome);
tvTipo = itemView.findViewById(R.id.cc_tv_tipo);
}
}
I've looked for some tutorials on the internet but none has specified what I want to do. Can someone help me?

Try to add this: orderByChild("type")
databaseReference = FirebaseDatabase.getInstance().getReference().child("usuario").orderByChild("type");
Or here:
options = new FirebaseRecyclerOptions.Builder<Usuario>().setQuery(databaseReference.orderByChild("type"), Usuario.class).build();
Sorry I can't test it right now, hope it works.

I have an idea may help in this set a flag for example called position with initial value 0 and create a new list to order on it and check the type and if is an admin add him in the list with position value and increase the position value else add the value without index
private int position = 0;
private List<Users> myList = new ArrayList();
for(int i = 0 ; i < usersList.size ; i++){
if(userList.get(i).getType.equal("adminstrator")){
myList.add(position,userList.get(i))
position++;
}else{
myList.add(usetList.get(i))
}
}
after set this list "myList" to the recyclerview adapter

Compare Old Data with New Data in Recyclerview

I am new in Android Development and working on a project where I need to call an API after every one second, in that API there is field "Amount"(dBID) which keeps on changing, so I need to update the latest Amount (dBID) in recyclerview.
In order to do so, I have called this API in a service after every interval of one second.
The data is Showing Properly no Issue.
But for Now I need to perform some action on the Old Amount and New Amount.
Action Required : I need to compare the old value (dBID) with the New Value (dBID).
If the New Value is greater then I need to change the Text Color of Amount (dBID) to BLUE.
If the New Value is smaller then I need to change the Text Color of Amount (dBID) to RED.
Tried to achieve this by storing the old data in a Variable and then Comparing it to the new Value.
Issue : This logic is working fine until there are 5 or less Items in recyclerview as soon as the sixth item is added the same logic does not work.
Help me if anyone knows how I can achieve this.
For Example you can refer an App Vertexfx : Quotes Tab.
Below is the Code which I Tried.
Adapter class of the RecyclerView:
public class QuoteAdapter extends RecyclerView.Adapter <QuoteAdapter.MyViewHolder>{
Context context;
List<QuoteData> data;
public QuoteAdapter(Context context,List<QuoteData> data)
{
this.data = data;
this.context = context;
}
class MyViewHolder extends RecyclerView.ViewHolder{
TextView time,symbol,sellmax,selllow,buymax,buylow,buy,sell,spread,lowtext,hightext;
LinearLayout layout,layoutbid,layoutask;
float currentbid,lastbid,currentask,lastask;
public MyViewHolder(#NonNull View itemView) {
super(itemView);
time = itemView.findViewById(R.id.TVTime);
symbol = itemView.findViewById(R.id.TVSymbol);
sellmax = itemView.findViewById(R.id.TVSELLMAX);
selllow = itemView.findViewById(R.id.TVSELLLOW);
buymax = itemView.findViewById(R.id.TVBUYMAX);
buylow = itemView.findViewById(R.id.TVBUYHIGH);
buy = itemView.findViewById(R.id.TVBUY);
sell = itemView.findViewById(R.id.TVSELL);
spread = itemView.findViewById(R.id.TVSpread1);
lowtext = itemView.findViewById(R.id.low);
hightext = itemView.findViewById(R.id.high);
layout = itemView.findViewById(R.id.layout);
layoutbid = itemView.findViewById(R.id.LLBid);
layoutask = itemView.findViewById(R.id.LLAsk);
currentbid = 0;
lastbid = 0;
currentask = 0;
lastask = 0;
}
}
#NonNull
#Override
public MyViewHolder onCreateViewHolder(#NonNull ViewGroup viewGroup, int i) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.quotelist,viewGroup,false);
return new MyViewHolder(view);
}
#SuppressLint("ResourceAsColor")
#Override
public void onBindViewHolder(#NonNull final MyViewHolder myViewHolder, final int i) {
final QuoteData data1 = data.get(i);
myViewHolder.time.setText(data1.dLut);
myViewHolder.symbol.setText(data1.dSymbol);
myViewHolder.sellmax.setText(data1.dBid); //Bid
myViewHolder.selllow.setText(data1.dLow);
myViewHolder.buymax.setText(data1.dAsk); //ask
myViewHolder.buylow.setText(data1.dHigh);
myViewHolder.currentbid = Float.parseFloat((data1.dBid));
myViewHolder.currentask = Float.parseFloat((data1.dAsk));
if (myViewHolder.currentbid > myViewHolder.lastbid)
{
myViewHolder.sellmax.setTextColor(Color.BLUE);
}
if (myViewHolder.currentbid < myViewHolder.lastbid)
{
myViewHolder.sellmax.setTextColor(Color.RED);
}
myViewHolder.lastbid = myViewHolder.currentbid;
myViewHolder.lastask = myViewHolder.currentask;
}
});
}

I suggest you take a look at those classes from the Android SDK:
DiffUtil
AsyncListDiffer
ItemAnimator
DiffUtil
DiffUtil is designed to compare existing and new recycler view items and fires appropriate events. You need to pass a callback that can tell if two items are the same and if their content has changed.
AsyncListDiffer
It wraps the DiffUtil and executes it's logic asynchronously, giving better performance.
ItemAnimator
The ItemAnimator for a given RecyclerView is called by default when change events are fired on it's items. You can provide an implementation of the animateChange method to change your color accordingly.

For Future reference I have resolved the above mentioned issue using the below code.
Defined two ArrayList of String in Adapter
public class QuoteAdapter extends RecyclerView.Adapter <QuoteAdapter.MyViewHolder>{
Context context;
List<QuoteData> data;
List<String> olddatabid = new ArrayList<String>();
List<String> newdatabid = new ArrayList<String>();
List<String> olddataask = new ArrayList<String>();
List<String> newdataask = new ArrayList<String>();
class MyViewHolder extends RecyclerView.ViewHolder{
TextView time,symbol,sellmax,selllow,buymax,buylow,buy,sell,spread,lowtext,hightext;
LinearLayout layout,layoutbid,layoutask;
public MyViewHolder(#NonNull View itemView) {
super(itemView);
time = itemView.findViewById(R.id.TVTime);
symbol = itemView.findViewById(R.id.TVSymbol);
sellmax = itemView.findViewById(R.id.TVSELLMAX);
selllow = itemView.findViewById(R.id.TVSELLLOW);
buymax = itemView.findViewById(R.id.TVBUYMAX);
buylow = itemView.findViewById(R.id.TVBUYHIGH);
buy = itemView.findViewById(R.id.TVBUY);
sell = itemView.findViewById(R.id.TVSELL);
spread = itemView.findViewById(R.id.TVSpread1);
lowtext = itemView.findViewById(R.id.low);
hightext = itemView.findViewById(R.id.high);
layout = itemView.findViewById(R.id.layout);
layoutbid = itemView.findViewById(R.id.LLBid);
layoutask = itemView.findViewById(R.id.LLAsk);
}
}
public QuoteAdapter(Context context,List<QuoteData> data)
{
this.data = data;
this.context = context;
}
#NonNull
#Override
public MyViewHolder onCreateViewHolder(#NonNull ViewGroup viewGroup, int i) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.quotelist,viewGroup,false);
return new MyViewHolder(view);
}
#SuppressLint("ResourceAsColor")
#Override
public void onBindViewHolder(#NonNull final MyViewHolder myViewHolder, final int i) {
final QuoteData data1 = data.get(i);
myViewHolder.time.setText(data1.dLut);
myViewHolder.symbol.setText(data1.dSymbol);
myViewHolder.sellmax.setText(data1.dBid); //Bid
myViewHolder.selllow.setText(data1.dLow);
myViewHolder.buymax.setText(data1.dAsk); //ask
myViewHolder.buylow.setText(data1.dHigh);
if (newdatabid.size()< data.size())
{
newdatabid.add(data1.dBid); //Insert Value in array for the first time
}
if (olddatabid.size()< data.size())
{
olddatabid.add(data1.dBid); //Insert Value in array for the first time
}
if (newdataask.size()< data.size())
{
newdataask.add(data1.dAsk); //Insert Value in array for the first time
}
if (olddataask.size()< data.size()) //Insert Value in array for the first time
{
olddataask.add(data1.dAsk);
}
newdatabid.set(i,data1.dBid); //Store Value in array
newdataask.set(i,data1.dAsk); //Store Value in array
//Compare and perform Logic
if (Float.valueOf(newdatabid.get(i)) > Float.valueOf(olddatabid.get(i)))
{
myViewHolder.sellmax.setTextColor(Color.BLUE);
}
if (Float.valueOf(newdatabid.get(i)) < Float.valueOf(olddatabid.get(i)))
{
myViewHolder.sellmax.setTextColor(Color.RED);
}
if (Float.valueOf(newdataask.get(i)) > Float.valueOf(olddataask.get(i)))
{
myViewHolder.buymax.setTextColor(Color.BLUE);
}
if (Float.valueOf(newdataask.get(i)) < Float.valueOf(olddataask.get(i)))
{
myViewHolder.buymax.setTextColor(Color.RED);
}
olddatabid.set(i,newdatabid.get(i));
olddataask.set(i,newdataask.get(i));
}
});
}
}
#Override
public int getItemCount() {
return data.size();
}
}

How to create a RecyclerView of Buttons

I am creating an AlertDialog custom class, called ActionDialog, which will contains a RecyclerView containing Buttons. I have a List of Button that I populate in the custom class ActionDialog (for now i just populate with useless Button just to try to use it, except one which I create in another class).
The problem is that when i create the AlertDialog, all buttons are showing empty, they are showed but with no text/no clicklistener (as you can see in the image below).
(I have added a custom ActionListener to a Button in another class and then give it as parameter in ActionDialog class. Will it lose the ActionListener?)
Here is the result.
I will leave here my ActionDialog class code, and the adapter class.
This is ActionDialog class:
public class ActionDialog extends AlertDialog{
private RecyclerView mRecyclerView;
private RecyclerView.Adapter mAdapter;
private RecyclerView.LayoutManager mLayoutManager;
private Button actionButtons;
private List<Button> buttons;
private Activity context;
public ActionDialog(#NonNull Activity context, Button actionButtons) {
super(context);
this.context = context;
this.actionButtons = actionButtons;
buttons = new ArrayList<>();
initButton();
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//requestWindowFeature(Window.FEATURE_NO_TITLE);
}
private void initButton(){
initZoneButton();
//TODO init all buttons
Button b1 = new Button(context);
b1.setText("ExampleButton1");
Button b2 = new Button(context);
b2.setText("ExampleButton2");
b1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String a;
}
});
buttons.add(b1);
buttons.add(b2);
}
private void initZoneButton(){
buttons.add(actionButtons); //this button is created in another class and give as parameter in this class
}
public void createDialog(){
Builder mBuilder = new Builder(context);
View view = context.getLayoutInflater().inflate(R.layout.dialog_actionbuttons_layout, null);
mRecyclerView = view.findViewById(R.id.dialog_actionbuttons_rv);
mRecyclerView.setHasFixedSize(true);
mLayoutManager = new LinearLayoutManager(context);
mRecyclerView.setLayoutManager(mLayoutManager);
mAdapter = new ActionButtonsAdapter(buttons);
mRecyclerView.setAdapter(mAdapter);
mBuilder.setView(view);
mBuilder.create().show();
}
}
Here is the RecyclerView adapter class:
public class ActionButtonsAdapter extends RecyclerView.Adapter<ActionButtonsAdapter.ViewHolder>{
private List<Button> dataButtons;
static class ViewHolder extends RecyclerView.ViewHolder {
Button actionButton;
ViewHolder(View v) {
super(v);
actionButton = v.findViewById(R.id.action_button_rv);
}
}
public ActionButtonsAdapter(List<Button> dataButtons){
this.dataButtons = dataButtons;
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.actionButton = dataButtons.get(position);
//i think the problem is here, maybe
}
#Override
public ActionButtonsAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType){
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_actionbutton_layout, parent, false);
return new ViewHolder(v);
}
#Override
public int getItemCount() {
return dataButtons.size();
}
}

I think in the onBindViewHolder method you should do what ever you want to do with your button.
Also there is no need for the list of buttons here. Make a list the data you need to be held in the Buttons RecyclerView.
I have a RecyclerView that will display Genres for restaurants lets say, So I will create a List of strings to hold these genres names (chickens, meats, etc,..)
Setting its text
holder.actionButton.setText(// Make use of position here);
Or Click Listeners.
Update
You can check google samples for recyclerview here
#Override
public void onBindViewHolder(ViewHolder viewHolder, final int position) {
Log.d(TAG, "Element " + position + " set.");
// Get element from your dataset at this position and replace the contents of the view
// with that element
viewHolder.getTextView().setText(mDataSet[position]);
}
wheres mDataset is Array of Strings.

Data on recycleview item is not correct when scroll

My adapter code:
public class BrandAdapter extends RecyclerView.Adapter<BrandAdapter.BrandViewHolder> {
private static final String TAG = BrandAdapter.class.getSimpleName();
private List<BrandItem> brands;
private Context context;
public BrandAdapter(Context context, List<BrandItem> data) {
this.context = context;
this.brands = data;
}
public void setData(List<BrandItem> dataDownload) {
this.brands = dataDownload;
}
#Override
public BrandViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.row_item_brand, null);
BrandViewHolder holder = new BrandViewHolder(view);
return holder;
}
#Override
public void onBindViewHolder(BrandViewHolder holder, int position) {
BrandItem brandItem = brands.get(position);
String name = brandItem.getName();
int count = brandItem.getCountArticles();
holder.tvName.setText(name);
if (count > 0) {
holder.tvCount.setText("" + count);
} else {
holder.tvCount.setVisibility(View.GONE);
}
}
#Override
public int getItemCount() {
return brands.size();
}
public static class BrandViewHolder extends RecyclerView.ViewHolder {
TextView tvName;
TextView tvCount;
public BrandViewHolder(View itemView) {
super(itemView);
tvName = (TextView) itemView.findViewById(R.id.tv_brand_name);
tvCount = (TextView) itemView.findViewById(R.id.tv_count_article);
}
}
}
Fragment code :
recyclerView = (RecyclerView) view.findViewById(R.id.recycleView);
linearLayoutManager = new LinearLayoutManager(getActivity());
recyclerView.setLayoutManager(linearLayoutManager);
adapter = new BrandAdapter(getActivity(), brands);
recyclerView.setAdapter(adapter);
Data for brands is downloaded from server. After downloaded finished, I just set new data for adapter by this code :
brands = downloadedBrands();
adapter.setData(brands);
adapter.notifyDataSetChanged();
Everything is Ok when data loaded for first time after the download finish. But when I scroll down the recycleview and scroll up again, data for each item is wrong now, all textview tvCount is gone. I do not know why.
Is there any problem from my code ?

Greenrobo's answer is correct but here is an explanation as to WHY you are having this issue.
You are assuming that your view is always set to the default values in your onBindViewHolder method.
The RecyclerView re-uses views that have scrolled off screen and therefore the view you are binding to may have already been previously used (and changed).
You onBindViewHolder method should always set EVERYTHING up. i.e all views reset to the exact values you want and do not assume that because you default an item to visible, it will always be so.

Please make tvCount visible when setting a non-zero count.
if (count > 0) {
holder.tvCount.setText("" + count);
holder.tvCount.setVisibility(View.VISIBLE);
} else {
holder.tvCount.setVisibility(View.GONE);
}
See if this helps.

You told that if count is less than 0, hide the view. What if count is greater than zero ? You are not making the view visible again. So simply make the below changes in your if condition:
if (count > 0) {
holder.tvCount.setText("" + count);
holder.tvCount.setVisibility(View.VISIBLE);
} else {
holder.tvCount.setVisibility(View.GONE);
}