Develop Reference

Facing error in onBindView() method in recyclerView

I am just practicing the RecyclerView. when I run the App my App crashed I check the log but i cant understand the problem can some help me im waiting for someone responce?
public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.ViewHolder> {
private model[] localDataSet;
private TextView name,number;
public static class ViewHolder extends RecyclerView.ViewHolder {
private final TextView textView;
public ViewHolder(View view) {
super(view);
textView = (TextView) view.findViewById(R.id.name);
}
public TextView getTextView() {
return textView;
}
}
public CustomAdapter(model[] dataSet) {
localDataSet = dataSet;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
// Create a new view, which defines the UI of the list item
View view = LayoutInflater.from(viewGroup.getContext())
.inflate(R.layout.contacx, viewGroup, false);
view.findViewById(R.id.name);
view.findViewById(R.id.number);
return new ViewHolder(view);
}
// Replace the contents of a view (invoked by the layout manager)
#Override
public void onBindViewHolder(ViewHolder viewHolder, final int position) {
name.setText(localDataSet[position].getName());
number.setText(localDataSet[position].getPhone());
}
#Override
public int getItemCount() {
return localDataSet.length;
}
}

You need to change the following things in your code:
public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.ViewHolder> {
private model[] localDataSet;
//remove this from here.
//private TextView name,number;
public static class ViewHolder extends RecyclerView.ViewHolder {
//This should be from the layout you have passed in ViewHolder method. in your case from R.layout.contacx. This layout should have two textview with ids:- name and phone respectively.
private final TextView name, phone;
public ViewHolder(View view) {
super(view);
name = view.findViewById(R.id.name);
phone = view.findViewById(R.id.phone);
}
}
public CustomAdapter(model[] dataSet) {
localDataSet = dataSet;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
// Create a new view, which defines the UI of the list item
View view = LayoutInflater.from(viewGroup.getContext())
.inflate(R.layout.contacx, viewGroup, false);
//remvoe this from here.
//view.findViewById(R.id.name);
//view.findViewById(R.id.number);
return new ViewHolder(view);
}
// Replace the contents of a view (invoked by the layout manager)
#Override
public void onBindViewHolder(ViewHolder viewHolder, final int position) {
//here you should call those view to bind your data like:
viewHolder.name.setText(localDataSet[position].getName());
viewHolder.phone.setText(String.valueOf(localDataSet[position].getPhone()));
}
#Override
public int getItemCount() {
return localDataSet.length;
}
}

Use ViewHolder for data bind. More safe
public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.ViewHolder> {
private model[] localDataSet;
public static class ViewHolder extends RecyclerView.ViewHolder {
private final TextView name, number;
public ViewHolder(View view) {
super(view);
name = view.findViewById(R.id.name);
number = view.findViewById(R.id.phone);
}
public void bindData(model data) {
name.setText(data.getName());
number.setText(String.valueOf(data.getPhone()));
}
}
public CustomAdapter(model[] dataSet) {
localDataSet = dataSet;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
/* No Need
View view = LayoutInflater.from(viewGroup.getContext())
.inflate(R.layout.contacx, viewGroup, false);
view.findViewById(R.id.name);
view.findViewById(R.id.number);
*/
return new ViewHolder(LayoutInflater.from(viewGroup.getContext())
.inflate(R.layout.contacx, viewGroup, false););
}
#Override
public void onBindViewHolder(ViewHolder viewHolder, final int position) {
/*
name.setText(localDataSet[position].getName());
number.setText(localDataSet[position].getPhone());
*/
viewHolder.bindData(localDataSet[position]);
}
#Override
public int getItemCount() {
return localDataSet.length;
}
}

Getting onSwipe event from a nested RecyclerView to the parent Fragment

I'm developping an app in which my main activity hosts different fragments via a SectionsPageAdapter. My question is about one of those fragments that roughtly looks like the image bellow:
My innerRecyclers lists differents items that I want to be able to remove by swiping and make the user validate the deletion via a DialogFragment. I was able to implement the swipe action but what I'm struggly to do is to implement a listener in the OuterRecycler for OnItemTouch so I can use an interface and send the action back to my fragment which will dispay my DialoFragment afterwards.
The code of my OuterRecycler currently looks like that:
public class OuterRecyclerAdapter extends RecyclerView.Adapter<OuterRecyclerAdapter.InsideRecyclerHolder> {
private final Context mContext;
private final String mText;
private final ArrayList<MainViewArrayListMasterList> mDataArrayList;
OuterRecyclerAdapter(Context context, ArrayList<MainViewArrayListMasterList> DataArrayList, String text) {
mContext = context;
mDataArrayList = RecyclerArrayListType;
mText = text;
}
#NonNull
#Override
public OuterRecyclerAdapter.InsideRecyclerHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
LayoutInflater myInflater = LayoutInflater.from(mContext);
View myOwnView = myInflater.inflate(R.layout.outer_recycler, parent, false);
return new OuterRecyclerAdapter.InsideRecyclerHolder(myOwnView);
}
#Override
public void onBindViewHolder(#NonNull OuterRecyclerAdapter.InsideRecyclerHolder holder, int position) {
MainViewArrayListMasterList currentItem = mDataArrayList.get(position);
holder.CardTitle.setText(String.valueOf(currentItem.getmYear()));
LinearLayoutManager mLayoutManager = new LinearLayoutManager(mContext, LinearLayoutManager.VERTICAL, false);
holder.CardRecycler.setLayoutManager(mLayoutManager);
InnerRecyclerAdapter historyInnerView_Adapter = new InnerRecyclerAdapter(mContext, currentItem.getmArrayListStored(), mText);
new ItemTouchHelper(ListHistoryViewSwiped).attachToRecyclerView(holder.CardRecycler);
holder.CardRecycler.setAdapter(historyInnerView_Adapter);
}
#Override
public int getItemCount() {
return mDataArrayList.size();
}
static class InsideRecyclerHolder extends RecyclerView.ViewHolder {
final TextView CardTitle;
final RecyclerView CardRecycler;
InsideRecyclerHolder(#NonNull View itemView) {
super(itemView);
CardTitle = itemView.findViewById(R.id.TitleText);
CardRecycler = itemView.findViewById(R.id.Inside_Recycler);
}
}
ItemTouchHelper.SimpleCallback ListHistoryViewSwiped = new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.RIGHT) {
#Override
public boolean onMove(#NonNull RecyclerView recyclerView, #NonNull RecyclerView.ViewHolder viewHolder, #NonNull RecyclerView.ViewHolder target) {
return false;
}
#Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
}
};
}
Is OnItemTouchListener the good way to acheive this ? Or do I have to create a new callback method ?

I actually circumvented this issue by calling the DialogFragment from my OuterRecycler:
public class OuterRecyclerAdapter extends RecyclerView.Adapter<OuterRecyclerAdapter.InsideRecyclerHolder> {
private final Context mContext;
private final String mText;
private final ArrayList<MainViewArrayListMasterList> mDataArrayList;
private FragmentManager mFragmentManager;
OuterRecyclerAdapter(Context context, FragmentManager FragmentManager, ArrayList<MainViewArrayListMasterList> DataArrayList, String text) {
mContext = context;
mFragmentManager = FragmentManager;
mDataArrayList = RecyclerArrayListType;
mText = text;
}
#NonNull
#Override
public OuterRecyclerAdapter.InsideRecyclerHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
LayoutInflater myInflater = LayoutInflater.from(mContext);
View myOwnView = myInflater.inflate(R.layout.outer_recycler, parent, false);
return new OuterRecyclerAdapter.InsideRecyclerHolder(myOwnView);
}
#Override
public void onBindViewHolder(#NonNull OuterRecyclerAdapter.InsideRecyclerHolder holder, int position) {
MainViewArrayListMasterList currentItem = mDataArrayList.get(position);
holder.CardTitle.setText(String.valueOf(currentItem.getmYear()));
LinearLayoutManager mLayoutManager = new LinearLayoutManager(mContext, LinearLayoutManager.VERTICAL, false);
holder.CardRecycler.setLayoutManager(mLayoutManager);
InnerRecyclerAdapter historyInnerView_Adapter = new InnerRecyclerAdapter(mContext, currentItem.getmArrayListStored(), mText);
new ItemTouchHelper(new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.RIGHT) {
#Override
public boolean onMove(#NonNull RecyclerView recyclerView, #NonNull RecyclerView.ViewHolder viewHolder, #NonNull RecyclerView.ViewHolder target) {
return false;
}
#Override
public void onSwiped(#NonNull RecyclerView.ViewHolder viewHolder, int direction) {
openMyDialog(currentItem.getmArrayListStored().get(viewHolder.getAdapterPosition()));
}
}).attachToRecyclerView(holder.CardRecycler);
holder.CardRecycler.setAdapter(historyInnerView_Adapter);
}
#Override
public int getItemCount() {
return mDataArrayList.size();
}
static class InsideRecyclerHolder extends RecyclerView.ViewHolder {
final TextView CardTitle;
final RecyclerView CardRecycler;
InsideRecyclerHolder(#NonNull View itemView) {
super(itemView);
CardTitle = itemView.findViewById(R.id.TitleText);
CardRecycler = itemView.findViewById(R.id.Inside_Recycler);
}
}
private void openMyDialog(MainViewArrayListRecycler itemToDelete) {
MyDialog myDialog = MyDialog.newInstance(itemToDelete);
myDialog.show(mFragmentManager, "MyDialogDialog");
}
}

RecyclerView Adapter won't inflate the correct layout

I'm trying to have my application display a specific layout when the arraylist PinnedSongs is empty.
I've created different viewholders and tried to inflate them depending on the PinnedSongs.size. Meaning, if it's 0, then the onCreateViewHolder should inflate a special layout. If it's different, then inflate another one.
public class RecyclerAdapterHome extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
public class Viewholder extends RecyclerView.ViewHolder implements View.OnClickListener{
CardView home_cardView;
TextView home_textView;
TextView home_textView_2;
Button home_button;
Button home_button_2;
RelativeLayout parentlayout;
OnNoteListener_2 onNoteListener2;
public Viewholder(#NonNull View itemView, OnNoteListener_2 onNoteListener_2) {
super(itemView);
home_cardView = itemView.findViewById(R.id.cardview_2);
home_textView = itemView.findViewById(R.id.cardview_2_textview);
home_textView_2 = itemView.findViewById(R.id.cardview_2_textview_sub);
home_button = itemView.findViewById(R.id.play_button);
home_button_2 = itemView.findViewById(R.id.push_button);
parentlayout = itemView.findViewById(R.id.home_parentlayout);
home_button.setOnClickListener(this);
this.onNoteListener2 = onNoteListener_2;
}
#Override
public void onClick(View v) {
onNoteListener2.onClick(getAdapterPosition());
}
}
public class Viewholder_2 extends RecyclerView.ViewHolder {
TextView textView_3;
ImageView imageView;
RelativeLayout parentlayout;
public Viewholder_2(#NonNull View itemView) {
super(itemView);
textView_3 = itemView.findViewById(R.id.text_warning);
imageView = itemView.findViewById(R.id.icon);
parentlayout = itemView.findViewById(R.id.home_parentlayout);
}
}
public RecyclerAdapterHome(OnNoteListener_2 mOnNoteListener2, ArrayList<String> pinnedSongs, ArrayList<String> pinnedSongsArtists, Context mContext) {
this.mOnNoteListener2 = mOnNoteListener2;
this.PinnedSongs = pinnedSongs;
this.PinnedSongsArtists = pinnedSongsArtists;
this.mContext = mContext;
}
private ArrayList<String> PinnedSongs = new ArrayList<>();
private ArrayList<String> PinnedSongsArtists = new ArrayList<>();
private Context mContext;
private OnNoteListener_2 mOnNoteListener2;
#NonNull
#Override
public RecyclerView.ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View v = null;
if (PinnedSongs.size()==0){
v = LayoutInflater.from(parent.getContext()).inflate(R.layout.nothing, parent, false);
return new Viewholder_2(v);
}else{
v = LayoutInflater.from(parent.getContext()).inflate(R.layout.homeviewholder,
parent, false);
return new Viewholder(v,mOnNoteListener2 );
}
}
#Override
public void onBindViewHolder(#NonNull RecyclerView.ViewHolder holder, int position) {
if (PinnedSongs.size()==0){
Viewholder_2 viewholder_2 = (Viewholder_2) holder;
}else{
Viewholder viewholder = (Viewholder) holder;
viewholder.home_textView.setText(PinnedSongs.get(position));
viewholder.home_textView_2.setText(PinnedSongsArtists.get(position));
}
}
#Override
public int getItemCount() {
return PinnedSongs.size();
}
public interface OnNoteListener_2 {
void onClick(int position);
}
}
So far, the recyclerview shows nothing when the PinnedSongs list is at zero. But it shows something when it's above zero. Any idea on how I can fix it?
(I'm using the androidx libraries if it has anything to do with that).

It doesn't work because the getItemCount method returns 0 and the RecyclerView never tries to instantiate a view.
It means that onBindViewHolder is not called when the size=0.
You have different options to do it. One of these is:
#Override
public int getItemCount() {
return PinnedSongs.size() > 0 ? PinnedSongs.size() : 1;
}
#Override
public int getItemViewType(int position) {
if (PinnedSongs.size() == 0) {
return EMPTY_VIEW;
}
return super.getItemViewType(position);
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v;
if (viewType == EMPTY_VIEW) {
v = LayoutInflater.from(parent.getContext()).inflate(R.layout.nothing, parent, false);
EmptyViewHolder emptyViewHolder = new EmptyViewHolder(v);
return emptyViewHolder;
}
//normal case
v = LayoutInflater.from(parent.getContext()).inflate(R.layout.homeviewholder, parent, false);
ViewHolder viewholder = new ViewHolder(v);
return viewholder;
}
public class EmptyViewHolder extends RecyclerView.ViewHolder {
public EmptyViewHolder(View itemView) {
super(itemView);
}
}
private static final int EMPTY_VIEW = 1000;

Using multiple views and data sets in RecyclerView

I have the following adapter which populates a RecyclerView with CardView items containing one TextView. It fills these TextViews with data from a String array. However, now I want to add another TextView to my CardViews and populate it with a separate data array, and I was wondering how I can best achieve this:
public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.ViewHolder> {
private String[] mDataset;
public static class ViewHolder extends RecyclerView.ViewHolder {
public TextView mTextView;
public ViewHolder(View itemView) {
super(itemView);
mTextView = (TextView)itemView.findViewById(R.id.grade);
}
}
public RecyclerAdapter(String[] myDataset) {
mDataset = myDataset;
}
#Override
public RecyclerAdapter.ViewHolder onCreateViewHolder(ViewGroup parent,
int viewType) {
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.card_item, parent, false);
ViewHolder vh = new ViewHolder(v);
return vh;
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.mTextView.setText(mDataset[position]);
}
#Override
public int getItemCount() {
return mDataset.length;
}
}
All help is appreciated as always!

Simply add another TextView or any other view in your CardLayout XML R.layout.card_item
Then
public TextView mTextView;
public TextView mTextView1;
public TextView mTextView2;
public TextView mTextView3;
public ViewHolder(View itemView) {
super(itemView);
mTextView = (TextView)itemView.findViewById(R.id.grade);
mTextView1 = (TextView)itemView.findViewById(R.id.grade1);
mTextView2 = (TextView)itemView.findViewById(R.id.grade2);
mTextView3 = (TextView)itemView.findViewById(R.id.grade3);
}
and finally set data to all the desired textviews as
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.mTextView.setText("String");
holder.mTextView1.setText("String");
holder.mTextView2.setText("String");
holder.mTextView3.setText("String");
}

Get Width and Height of one row in RecycleView - Android

I'm creating RecycleView with some items. So I need to get the width and height of the one row of RecycleView
Here I'm creating RecycleView:
RecyclerView rvSmetki = (RecyclerView) findViewById(R.id.rvArtikli);
rvSmetki.setLayoutManager(new GridLayoutManager(this, 3););
rvSmetki.setAdapter(new ArtikliAdapter(this));
// Here I want to get width and height....
And this is my ArtikliAdapter:
public class ArtikliAdapter extends RecyclerView.Adapter<ArtikliAdapter.ViewHolder> {
private static Context context;
private LayoutInflater inflater;
private ArrayList<Artikl> artikliList;
public ArtikliAdapter(Context context) {
this.context = context;
inflater = LayoutInflater.from(context);
artikliList = LogInActivity.getArtiklList();
}
#Override
public ArtikliAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View row = inflater.inflate(R.layout.artikli_row, parent, false);
return new ArtikliAdapter.ViewHolder(row);
}
#Override
public void onBindViewHolder(ArtikliAdapter.ViewHolder holder, int position) {
Artikl currentArtikl = artikliList.get(position);
holder.tvNaziv.setText(currentArtikl.getNaziv());
holder.tvCena.setText("Цена: " + currentArtikl.getProdaznaCena());
}
#Override
public int getItemCount() {
return artikliList.size();
}
static class ViewHolder extends RecyclerView.ViewHolder {
private RelativeLayout rlArtikl;
private TextView tvNaziv;
private TextView tvCena;
public ViewHolder(View itemView) {
super(itemView);
rlArtikl = (RelativeLayout) itemView.findViewById(R.id.rlArtikl);
tvNaziv = (TextView) itemView.findViewById(R.id.tvNaziv);
tvCena = (TextView) itemView.findViewById(R.id.tvCena);
}
}
}
How can I get width and height of one row?

#Override
public void onBindViewHolder(final MyAdapter.MyViewHolder holder, int position)
{
.....
holder.itemView.post(new Runnable()
{
#Override
public void run()
{
int cellWidth = holder.itemView.getWidth();// this will give you cell width dynamically
int cellHeight = holder.itemView.getHeight();// this will give you cell height dynamically
}
});
.....
}
I hope this will help you!!