Develop Reference

Change image view background of View Pager2 selected image in android

I am trying to changing the background imageview of viewpager2 selected imageview in android. But in my case not changing image view background, when viewpager2 selected. Below code to change image view background.
final List<Integer> names = new ArrayList<Integer>();
for(int i=0;i<5;i++){
names.add(i);
}
insideRoomAdapter = new InsideRoomAdapter(context,names);
viewPager.setAdapter(insideRoomAdapter);
viewPager.registerOnPageChangeCallback(new ViewPager2.OnPageChangeCallback() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
super.onPageScrolled(position, positionOffset, positionOffsetPixels);
}
#Override
public void onPageSelected(int position) {
super.onPageSelected(position);
for(int i=0;i<names.size();i++){
if(names.get(position) == position){
Toast.makeText(context,"pos:"+ names.get(position),Toast.LENGTH_SHORT).show();
insideRoomAdapter.imageView.setBackground(ContextCompat.getDrawable(context,R.drawable.selected_light_bg));
viewPager.getAdapter().notifyDataSetChanged();
}else {
insideRoomAdapter.imageView.setBackground(ContextCompat.getDrawable(context,R.drawable.inside_room_item_bg));
viewPager.getAdapter().notifyDataSetChanged();
}
}
}
#Override
public void onPageScrollStateChanged(int state) {
super.onPageScrollStateChanged(state);
}
});
My Adapter class
public class InsideRoomAdapter extends RecyclerView.Adapter<InsideRoomAdapter.ViewHolder> {
Context context;
List<Integer> list;
ImageView imageView;
public InsideRoomAdapter(Context context,List<Integer> list) {
this.context = context;
this.list = list;
}
#NonNull
#Override
public InsideRoomAdapter.ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(context).inflate(R.layout.inside_room_items,parent,false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull InsideRoomAdapter.ViewHolder holder, int position) {
imageView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Toast.makeText(context,"light clicked",Toast.LENGTH_LONG).show();
}
});
}
#Override
public int getItemCount() {
return list.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
public ViewHolder(#NonNull View itemView) {
super(itemView);
imageView = itemView.findViewById(R.id.inside_light_img);
}
}
}
Anyone can guide me how to change image view background, when viewpager2 selected.
Expected like this
Thanks in Advance.

I think you are approaching this in the wrong way. What you need is a public method for your adapter which stores the position selected from your viewpager2's onPageSelected() and in onBindViewHolder() method of your adapter simply use a check for selecting the background to use.
I have made changes to your adapter as below:
public class InsideRoomAdapter extends RecyclerView.Adapter<InsideRoomAdapter.ViewHolder> {
private Context context;
private List<Integer> list;
//moved ImageView to ViewHolder class as private
private int selectedPosition; //the int value for keeping track of your selected position
public InsideRoomAdapter(Context context,List<Integer> list) {
this.context = context;
this.list = list;
this.selectedPosition = 0; //initialize it here
}
#NonNull
#Override
public InsideRoomAdapter.ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(context).inflate(R.layout.inside_room_items,parent,false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull InsideRoomAdapter.ViewHolder holder, int position) {
/* Since ImageView was moved reference it from the holder like below
* Use a simple check to verify it the adapter position matches with the selectedPosition
* if so simply set the backgrounds as required
*/
if(position == selectedPosition) {
holder.imageView.setBackground(ContextCompat.getDrawable(context,R.drawable.selected_light_bg));
} else {
holder.imageView.setBackground(ContextCompat.getDrawable(context,R.drawable.inside_room_item_bg));
}
holder.imageView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Toast.makeText(context,"light clicked",Toast.LENGTH_LONG).show();
}
});
}
public void setSelectedPosition(int newPosition) {
this.selectedPosition = newPosition;
notifyDataSetChanged();
/* If you require better animations make use of notifyItemChanged() instead
* save selectedPosition value in a temp variable before swap
* and call notifyItemChanged() for both positions old and new
*/
}
#Override
public int getItemCount() {
return list.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
private ImageView imageView;
public ViewHolder(#NonNull View itemView) {
super(itemView);
imageView = itemView.findViewById(R.id.inside_light_img);
}
}
}
And then instead of complicating your code your onPageSelected() should eb something like this
#Override
public void onPageSelected(int position) {
super.onPageSelected(position);
insideRoomAdapter.setSelectedPosition(position);
}
That's all, let us know if this answer helped solve your issue.

I want to make my buttons in recyclerView toggleable means when clicked on one other all should be dssleted

when i click on one button others should be deselected how to achieve this
I have seen other answers in stack but none solved my problem or i was not able to undrestand properly
public class LocationAreaAdapter extends RecyclerView.Adapter<LocationAreaAdapter.ViewHolder> {
private int mSelectedItem = -1;
private ArrayList<String> mNames = new ArrayList<>();
private Context mContext;
private ArrayList<Boolean> isChecked=new ArrayList<>();
private AdapterView.OnItemClickListener onItemClickListener;
public LocationAreaAdapter(Context context,ArrayList<String> mNames ){
this.mContext=context;
this.mNames=mNames;
}
#NonNull
#Override
public ViewHolder onCreateViewHolder(#NonNull ViewGroup viewGroup, int i) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.locatin_area_cardview, viewGroup, false);
return new ViewHolder(view,this);
}
#Override
public void onBindViewHolder(#NonNull ViewHolder holder, int i) {
holder.name.setText(mNames.get(i));
holder.name.setChecked(i == mSelectedItem);
//what to do here
}
#Override
public int getItemCount() {
return mNames.size();
}
public void onItemHolderClick(ViewHolder holder) {
if (onItemClickListener != null)
onItemClickListener.onItemClick(null, holder.itemView, holder.getAdapterPosition(), holder.getItemId());
}
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
RadioButton name;
LocationAreaAdapter mAdapter;
public ViewHolder(View itemView, final LocationAreaAdapter mAdapter) {
super(itemView);
this.mAdapter = mAdapter;
name = itemView.findViewById(R.id.location_area_button);
itemView.setOnClickListener(this);
name.setOnClickListener(this);
}
#Override
public void onClick(View v) {
mSelectedItem = getAdapterPosition();
notifyItemRangeChanged(0, mNames.size());
mAdapter.onItemHolderClick(ViewHolder.this);
}
}
}
when i click on the button the button is not clicked rather recyclerview flashes

When you click to viewholder item select position of current and deselect other viewholder position:
holder.name.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
mSelectedItem = position;
notifyDataSetChanged();
}
});
if (mSelectedItem==position ) {
//viewHolder.item.setVisibility(View.VISIBLE);
show itew here.
} else {
// viewHolder.item.setVisibility(View.GONE);
hideitew here.
}

Inflate multiple layout in FirestoreRecyclerAdapter [duplicate]

My Title is kind of hard to understand but basically when I add items into my database is should display it in a RecyclerView. Now in my RecyclerView I have two layouts but the problem is the first item of my database goes behind my first item in my other layout. So if I have 3 items in my database, it shows only 2 items from the database and the first item hides behind my first item in the RecyclerView which is a different layout that does not use the database at all.
This is my code:
FirebaseRecyclerOptions<Event> firebaseRecyclerOptions = new FirebaseRecyclerOptions.Builder<Event>()
.setQuery(query1, Event.class).build();
AccAdapter = new FirebaseRecyclerAdapter<Event, RecyclerView.ViewHolder>(firebaseRecyclerOptions){
final static int TYPE_HEADER = 0;
final static int TYPE_ITEM = 1;
#Override
public int getItemViewType(int position) {
if (position == 0) return TYPE_HEADER;
return TYPE_ITEM;
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == TYPE_HEADER){
View view = LayoutInflater.from(getActivity()).inflate(R.layout.recycler_view_row_add_items,
parent, false);
return new ProdudctHolder3(view);
} else {
View view = LayoutInflater.from(getActivity()).inflate(R.layout.recycler_view_row_acc,
parent, false);
return new ProductHolder2(view);
}
}
#Override
protected void onBindViewHolder(final RecyclerView.ViewHolder holder, int position, final Event model) {
if (holder instanceof ProdudctHolder3){
((ProdudctHolder3) holder).addBackground.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
startActivity(new Intent(getActivity(), AccAddItems.class ));
}
});
} else{
final ProductHolder2 productHolder2 = (ProductHolder2) holder;
productHolder2.mName.setText(model.getName());
productHolder2.view.setBackgroundResource(getBackgroundDrawable(Integer.valueOf(model.getProductAmount())));
productHolder2.mbackground.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
dialog = new Dialog(getActivity());
dialog.setContentView(R.layout.popup_edit_product);
SeekBar amountSeekBar = dialog.findViewById(R.id.amountSeekBar);
amountSeekBar.setMax(100);
amountSeekBar.setProgress(Integer.valueOf(model.getProductAmount()));
amountSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
#Override
public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
progress = i;
}
#Override
public void onStartTrackingTouch(SeekBar seekBar) {
}
#Override
public void onStopTrackingTouch(SeekBar seekBar) {
getRef(holder.getAdapterPosition()).child("productAmount").setValue(String.valueOf(progress));
dialog.dismiss();
}
});
dialog.show();
}
});
productHolder2.mbackground.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View view) {
final PopupMenu popupMenu = new PopupMenu(getActivity(), productHolder2.mbackground);
popupMenu.inflate(R.menu.menu_acc);
popupMenu.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
#Override
public boolean onMenuItemClick(MenuItem menuItem) {
switch (menuItem.getItemId()){
case R.id.deleteProduct:
getRef(productHolder2.getAdapterPosition()).removeValue();
popupMenu.dismiss();
return true;
default:
return false;
}
}
});
popupMenu.show();
return true;
}
});
}
}
};
mAccRecyclerViewRef.setAdapter(AccAdapter);
My two Product Holders
private class ProdudctHolder3 extends RecyclerView.ViewHolder{
private RelativeLayout addBackground;
public ProdudctHolder3(View itemView) {
super(itemView);
addBackground = itemView.findViewById(R.id.mBackground2);
}
}
private class ProductHolder2 extends RecyclerView.ViewHolder{
private TextView mName;
private RelativeLayout mbackground;
private View view;
public ProductHolder2(View itemView) {
super(itemView);
mName = itemView.findViewById(R.id.ItemName);
mbackground = itemView.findViewById(R.id.mBackground1);
view = itemView.findViewById(R.id.amountIndicator);
}
}

The ideal solution would have been to set two adapters on a single RecyclerView but unfortunatelly this is not possible.
However, you can make a single custom Adapter that handles two types of items. I will explain this by getting an example.
Let's assume you need to display objects of two types, humans and aliens. Your objects require completely different layouts and completely different ViewHolders. Please see the below code for the ViewHolders:
public class MyAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private static class HumanViewHolder extends RecyclerView.ViewHolder {
public HumanViewHolder(View itemView) {
super(itemView);
//Prepare your ViewHolder
}
public void bind(Human human) {
//Display your human object
}
}
private static class AlienViewHolder extends RecyclerView.ViewHolder {
public AlienViewHolder(View itemView) {
super(itemView);
//Prepare your ViewHolder
}
public void bind(Alien alien) {
//Display your alien object
}
}
}
First you need to add two different constants to your adapter representing both type of views:
private static final int ITEM_TYPE_HUMAN;
private static final int ITEM_TYPE_ALIEN;
To keep things simple, let's also assume you store your objects in a list:
private List<Object> items = new ArrayList<>();
public MyAdapter(List<Object> items) {
this.items.addAll(items);
//Other stuff if needed
}
Now, the first you need to do, is to implement getItemViewType() method:
#Override
public int getItemViewType(int position) {
if (items.get(position) instanceof Human) {
return ITEM_TYPE_HUMAN;
} else {
return ITEM_TYPE_ALIEN;
}
}
Second, you need to use the item type inside the onCreateViewHolder() method like this:
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
if (viewType == ITEM_TYPE_HUMAN) {
View view = layoutInflater.inflate(R.layout.item_human, parent, false);
return new HumanViewHolder(view);
} else {
View view = layoutInflater.inflate(R.layout.item_alien, parent, false);
return new AlienViewHolder(view);
}
}
In the end, you just need to bind the proper view holder like this:
#Override
public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) {
Object item = items.get(position);
if (viewHolder instanceof HumanViewHolder) {
((HumanViewHolder) viewHolder).bind((Human) item);
} else {
((AlienViewHolder) viewHolder).bind((Alien) item);
}
}

Why use the Firebase Recycler Adapter when you could easily make a custom one? If I understood well you want an item to be fixed at position 0 (header) while others will be added below the first one, right? If so, here is a solution I like to use:
public interface ViewType {
public int getViewType();
}
public interface ViewTypeDelegateAdapter {
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent);
public void onBindViewHolder(RecyclerView.ViewHolder holder, ViewType item);
}
public class ViewTypes {
public static int HEADER = 0
public static int ITEM = 1
}
public class ProductDelegateAdapter implements ViewTypeDelegateAdapter {
private int resID;
private Context context;
public ProductDelegateAdapter(int resID, Context context) {
this.resID = resID;
this.context = context;
}
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent) {
return new ProductHolder(LayoutInflater.from(parent.context).inflate(resID, parent, false));
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, ViewType item) {
(holder as ProductHolder).bind("test");
}
class ProductHolder extends RecyclerView.ViewHolder {
public ProductHolder(View view) {
super(view);
}
public void bind(String test) {
}
}
}
public class HeaderDelegateAdapter implements ViewTypeDelegateAdapter {
private int resID;
private Context context;
public ProductDelegateAdapter(int resID, Context context) {
this.resID = resID;
this.context = context;
}
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent) {
return new HeaderHolder(LayoutInflater.from(parent.context).inflate(resID, parent, false));
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, ViewType item) {
(holder as HeaderHolder).bind("test");
}
class HeaderHolder extends RecyclerView.ViewHolder {
public HeaderHolder(View view) {
super(view);
}
public void bind(String test) {
}
}
}
public class AccAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>() {
private Context context;
private List<ViewType> items;
private SparseArrayCompat<ViewTypeDelegateAdapter> delegateAdapters;
private ViewType headerItem;
public AccAdapter(Context context) {
this.context = context;
this.items = new ArrayList();
this.delegateAdapters = new SparseArrayCompat();
this.headerItem = new ViewType() {
#Override
public int getViewType() {
return ViewTypes.HEADER;
}
};
this.items.add(this.headerItem);
this.delegateAdapters.put(ViewTypes.HEADER, HeaderDelegateAdapter(R.id.test, this.context));
this.delegateAdapters.put(ViewTypes.ITEM, ProductDelegateAdapter(R.id.test, this.context));
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, Int viewType) {
return delegateAdapters.get(viewType).onCreateViewHolder(parent);
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, Int position) {
delegateAdapters.get(getItemViewType(position)).onBindViewHolder(holder, items[position])
}
#Override
public Int getItemViewType(Int position) {
return items.get(position).getViewType();
}
#Override
public Int getItemCount() {
return items.getSize();
}
public void add(ViewType viewType) {
val initPosition = this.items.size - 1
this.items.add(item)
notifyItemRangeChanged(initPosition, this.items.size + 1)
}
}
public class Event implements ViewType {
private String id;
#Override
public int getViewType() {
return ViewTypes.ITEM;
}
}
Excuse me for some syntax errors, I've translated to Java from Kotlin to help you. Hope it helps!

How to autoselect 1st item from RecyclerView?

I have a recyclerView in my app that contain a list of Menu and when i press one of them if will change items in another recyclerView but when i open my activity noone of recyclerView where there are the menu's are selected.
So the question is how can i open the activity and find the 1st item of the recyclerView selected?
I was trying to simulate an click by Handler but it was making my app slower.
Here is the code from my Adapter :
public class RecyclerViewMenu extends RecyclerView.Adapter<RecyclerViewMenu.MenuViewHolder> {
private ArrayList<MenuConstructor> menuConstructors;
private OnItemClickListener onItemClickListener;
private int selected_position = -1;
public interface OnItemClickListener {
void onItemClick(int position);
}
public void setOnItemClickListener(OnItemClickListener listener){
onItemClickListener = listener;
}
#NonNull
#Override
public MenuViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.menucard,parent,false);
return new MenuViewHolder(v, onItemClickListener);
}
RecyclerViewMenu(ArrayList<MenuConstructor> menuList){
menuConstructors = menuList;
}
#Override
public void onBindViewHolder(#NonNull final MenuViewHolder holder, final int position) {
MenuConstructor currentItem = menuConstructors.get(position);
if (selected_position == position) {
holder.itemView.setBackgroundColor(Color.parseColor("#2e7d32"));
} else {
holder.itemView.setBackgroundColor(Color.parseColor(currentItem.getSfondoColor()));
}
holder.textView.setText(currentItem.getDesk());
holder.textView.setTextColor(Color.parseColor(currentItem.getFontColor()));
}
#Override
public int getItemCount() {
return menuConstructors.size();
}
public class MenuViewHolder extends RecyclerView.ViewHolder {
public TextView textView;
MenuViewHolder(View itemView, final OnItemClickListener listener) {
super(itemView);
textView = itemView.findViewById(R.id.ButtonName);
itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(listener != null){
int position = getAdapterPosition();
if (position != RecyclerView.NO_POSITION){
listener.onItemClick(position);
selected_position = position;
notifyDataSetChanged();
}
}
}
});
}
}
}
And here is a screenshot of my activity as you can see "CICCIO" is my first item of the recyclerView but it was selected manually.

Have you tried this in your activity:
recyclerView.findViewHolderForAdapterPosition(0).itemView.performClick()

The variable selected_position should be public in a Utils class and then you set selected_position = 0 in onCreate:
public class Utils {
public static final int selected_position = -1;
}
then you use it in onCreate Utils.selected_position = 0;
and in onBindViewHolder if (position == Utils.selected_position)
Of course you have to remove this line: private int selected_position = -1;

Hi you can use performClick() function..
if(positon == 0)
holder.itemView.performClick();

FirebaseRecyclerAdapter doesn't recognize first layout as a position

My Title is kind of hard to understand but basically when I add items into my database is should display it in a RecyclerView. Now in my RecyclerView I have two layouts but the problem is the first item of my database goes behind my first item in my other layout. So if I have 3 items in my database, it shows only 2 items from the database and the first item hides behind my first item in the RecyclerView which is a different layout that does not use the database at all.
This is my code:
FirebaseRecyclerOptions<Event> firebaseRecyclerOptions = new FirebaseRecyclerOptions.Builder<Event>()
.setQuery(query1, Event.class).build();
AccAdapter = new FirebaseRecyclerAdapter<Event, RecyclerView.ViewHolder>(firebaseRecyclerOptions){
final static int TYPE_HEADER = 0;
final static int TYPE_ITEM = 1;
#Override
public int getItemViewType(int position) {
if (position == 0) return TYPE_HEADER;
return TYPE_ITEM;
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == TYPE_HEADER){
View view = LayoutInflater.from(getActivity()).inflate(R.layout.recycler_view_row_add_items,
parent, false);
return new ProdudctHolder3(view);
} else {
View view = LayoutInflater.from(getActivity()).inflate(R.layout.recycler_view_row_acc,
parent, false);
return new ProductHolder2(view);
}
}
#Override
protected void onBindViewHolder(final RecyclerView.ViewHolder holder, int position, final Event model) {
if (holder instanceof ProdudctHolder3){
((ProdudctHolder3) holder).addBackground.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
startActivity(new Intent(getActivity(), AccAddItems.class ));
}
});
} else{
final ProductHolder2 productHolder2 = (ProductHolder2) holder;
productHolder2.mName.setText(model.getName());
productHolder2.view.setBackgroundResource(getBackgroundDrawable(Integer.valueOf(model.getProductAmount())));
productHolder2.mbackground.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
dialog = new Dialog(getActivity());
dialog.setContentView(R.layout.popup_edit_product);
SeekBar amountSeekBar = dialog.findViewById(R.id.amountSeekBar);
amountSeekBar.setMax(100);
amountSeekBar.setProgress(Integer.valueOf(model.getProductAmount()));
amountSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
#Override
public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
progress = i;
}
#Override
public void onStartTrackingTouch(SeekBar seekBar) {
}
#Override
public void onStopTrackingTouch(SeekBar seekBar) {
getRef(holder.getAdapterPosition()).child("productAmount").setValue(String.valueOf(progress));
dialog.dismiss();
}
});
dialog.show();
}
});
productHolder2.mbackground.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View view) {
final PopupMenu popupMenu = new PopupMenu(getActivity(), productHolder2.mbackground);
popupMenu.inflate(R.menu.menu_acc);
popupMenu.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
#Override
public boolean onMenuItemClick(MenuItem menuItem) {
switch (menuItem.getItemId()){
case R.id.deleteProduct:
getRef(productHolder2.getAdapterPosition()).removeValue();
popupMenu.dismiss();
return true;
default:
return false;
}
}
});
popupMenu.show();
return true;
}
});
}
}
};
mAccRecyclerViewRef.setAdapter(AccAdapter);
My two Product Holders
private class ProdudctHolder3 extends RecyclerView.ViewHolder{
private RelativeLayout addBackground;
public ProdudctHolder3(View itemView) {
super(itemView);
addBackground = itemView.findViewById(R.id.mBackground2);
}
}
private class ProductHolder2 extends RecyclerView.ViewHolder{
private TextView mName;
private RelativeLayout mbackground;
private View view;
public ProductHolder2(View itemView) {
super(itemView);
mName = itemView.findViewById(R.id.ItemName);
mbackground = itemView.findViewById(R.id.mBackground1);
view = itemView.findViewById(R.id.amountIndicator);
}
}

The ideal solution would have been to set two adapters on a single RecyclerView but unfortunatelly this is not possible.
However, you can make a single custom Adapter that handles two types of items. I will explain this by getting an example.
Let's assume you need to display objects of two types, humans and aliens. Your objects require completely different layouts and completely different ViewHolders. Please see the below code for the ViewHolders:
public class MyAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private static class HumanViewHolder extends RecyclerView.ViewHolder {
public HumanViewHolder(View itemView) {
super(itemView);
//Prepare your ViewHolder
}
public void bind(Human human) {
//Display your human object
}
}
private static class AlienViewHolder extends RecyclerView.ViewHolder {
public AlienViewHolder(View itemView) {
super(itemView);
//Prepare your ViewHolder
}
public void bind(Alien alien) {
//Display your alien object
}
}
}
First you need to add two different constants to your adapter representing both type of views:
private static final int ITEM_TYPE_HUMAN;
private static final int ITEM_TYPE_ALIEN;
To keep things simple, let's also assume you store your objects in a list:
private List<Object> items = new ArrayList<>();
public MyAdapter(List<Object> items) {
this.items.addAll(items);
//Other stuff if needed
}
Now, the first you need to do, is to implement getItemViewType() method:
#Override
public int getItemViewType(int position) {
if (items.get(position) instanceof Human) {
return ITEM_TYPE_HUMAN;
} else {
return ITEM_TYPE_ALIEN;
}
}
Second, you need to use the item type inside the onCreateViewHolder() method like this:
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
if (viewType == ITEM_TYPE_HUMAN) {
View view = layoutInflater.inflate(R.layout.item_human, parent, false);
return new HumanViewHolder(view);
} else {
View view = layoutInflater.inflate(R.layout.item_alien, parent, false);
return new AlienViewHolder(view);
}
}
In the end, you just need to bind the proper view holder like this:
#Override
public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) {
Object item = items.get(position);
if (viewHolder instanceof HumanViewHolder) {
((HumanViewHolder) viewHolder).bind((Human) item);
} else {
((AlienViewHolder) viewHolder).bind((Alien) item);
}
}

Why use the Firebase Recycler Adapter when you could easily make a custom one? If I understood well you want an item to be fixed at position 0 (header) while others will be added below the first one, right? If so, here is a solution I like to use:
public interface ViewType {
public int getViewType();
}
public interface ViewTypeDelegateAdapter {
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent);
public void onBindViewHolder(RecyclerView.ViewHolder holder, ViewType item);
}
public class ViewTypes {
public static int HEADER = 0
public static int ITEM = 1
}
public class ProductDelegateAdapter implements ViewTypeDelegateAdapter {
private int resID;
private Context context;
public ProductDelegateAdapter(int resID, Context context) {
this.resID = resID;
this.context = context;
}
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent) {
return new ProductHolder(LayoutInflater.from(parent.context).inflate(resID, parent, false));
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, ViewType item) {
(holder as ProductHolder).bind("test");
}
class ProductHolder extends RecyclerView.ViewHolder {
public ProductHolder(View view) {
super(view);
}
public void bind(String test) {
}
}
}
public class HeaderDelegateAdapter implements ViewTypeDelegateAdapter {
private int resID;
private Context context;
public ProductDelegateAdapter(int resID, Context context) {
this.resID = resID;
this.context = context;
}
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent) {
return new HeaderHolder(LayoutInflater.from(parent.context).inflate(resID, parent, false));
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, ViewType item) {
(holder as HeaderHolder).bind("test");
}
class HeaderHolder extends RecyclerView.ViewHolder {
public HeaderHolder(View view) {
super(view);
}
public void bind(String test) {
}
}
}
public class AccAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>() {
private Context context;
private List<ViewType> items;
private SparseArrayCompat<ViewTypeDelegateAdapter> delegateAdapters;
private ViewType headerItem;
public AccAdapter(Context context) {
this.context = context;
this.items = new ArrayList();
this.delegateAdapters = new SparseArrayCompat();
this.headerItem = new ViewType() {
#Override
public int getViewType() {
return ViewTypes.HEADER;
}
};
this.items.add(this.headerItem);
this.delegateAdapters.put(ViewTypes.HEADER, HeaderDelegateAdapter(R.id.test, this.context));
this.delegateAdapters.put(ViewTypes.ITEM, ProductDelegateAdapter(R.id.test, this.context));
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, Int viewType) {
return delegateAdapters.get(viewType).onCreateViewHolder(parent);
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, Int position) {
delegateAdapters.get(getItemViewType(position)).onBindViewHolder(holder, items[position])
}
#Override
public Int getItemViewType(Int position) {
return items.get(position).getViewType();
}
#Override
public Int getItemCount() {
return items.getSize();
}
public void add(ViewType viewType) {
val initPosition = this.items.size - 1
this.items.add(item)
notifyItemRangeChanged(initPosition, this.items.size + 1)
}
}
public class Event implements ViewType {
private String id;
#Override
public int getViewType() {
return ViewTypes.ITEM;
}
}
Excuse me for some syntax errors, I've translated to Java from Kotlin to help you. Hope it helps!