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Pass data from recyclerView to another in fragment

I want to pass data from recyclerview to another both in fragment, first adapter
for display item, and second adapter for basket fragment that want to put selected item in.
Adapter I want to take data from:
public class FruitItemAdapter extends RecyclerView.Adapter<FruitItemAdapter.viewHolder> {
ArrayList<FruitItem> fruitItems = new ArrayList<>();
private Context context;
public FruitItemAdapter(ArrayList<FruitItem> fruitItems, Context context) {
this.fruitItems = fruitItems;
this.context = context;
notifyDataSetChanged();
}
public FruitItemAdapter() {
}
#NonNull
#Override
public viewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view =
LayoutInflater.from(parent.getContext()).inflate(R.layout.fruits_item,parent,false);
viewHolder viewHolder = new viewHolder(view);
return viewHolder;
}
#Override
public void onBindViewHolder(#NonNull viewHolder holder, int position) {
final FruitItem data_position = fruitItems.get(position);
holder.fruit_img.setImageResource(fruitItems.get(position).getFruit_img());
holder.fruit_name.setText(fruitItems.get(position).getFruit_name());
holder.fruit_price.setText(fruitItems.get(position).getFruit_price());
}
#Override
public int getItemCount() {
return fruitItems.size();
}
public void setfruitItem(ArrayList<FruitItem> fruitItems) {
this.fruitItems = fruitItems;
}
public static class viewHolder extends RecyclerView.ViewHolder {
private ImageView fruit_img;
private TextView fruit_price, fruit_name;
public viewHolder(#NonNull View itemView) {
super(itemView);
fruit_img = itemView.findViewById(R.id.fruit_img);
fruit_price = itemView.findViewById(R.id.fruit_price);
fruit_name = itemView.findViewById(R.id.fruit_name)
}
}
}
this is adapter for basket fragment that I want to put the data in
public class Basket_Adapter extends RecyclerView.Adapter<Basket_Adapter.viewHolder> {
private Context context;
ArrayList<FruitItem> fruitItems = new ArrayList<>();
public Basket_Adapter(Context context, ArrayList<FruitItem> fruitItems) {
this.context = context;
this.fruitItems = fruitItems;
notifyDataSetChanged();
}
public Basket_Adapter(){
}
#NonNull
#Override
public Basket_Adapter.viewHolder onCreateViewHolder(#NonNull ViewGroup parent, int
viewType) {
View view=LayoutInflater.from(parent.getContext()).inflate(R.layout.fruits_item,parent,false);
viewHolder viewHolder = new viewHolder(view);
return viewHolder;
}
#Override
public void onBindViewHolder(#NonNull Basket_Adapter.viewHolder holder, int position) {
holder.fruit_img.setImageResource(fruitItems.get(position).getFruit_img());
holder.fruit_name.setText(fruitItems.get(position).getFruit_name());
holder.fruit_price.setText(fruitItems.get(position).getFruit_price());
}
#Override
public int getItemCount() {
return fruitItems.size();
}
public void setfruitItem(ArrayList<FruitItem> fruitItems) {
this.fruitItems = fruitItems;
}
public class viewHolder extends RecyclerView.ViewHolder {
private ImageView fruit_img;
private TextView fruit_name;
private TextView fruit_price;
public viewHolder(#NonNull View itemView) {
super(itemView);
fruit_img = itemView.findViewById(R.id.fruit_img);
fruit_name = itemView.findViewById(R.id.fruit_name);
fruit_price = itemView.findViewById(R.id.fruit_price);
}
}
Now, what I can use to pass data between them.

You can achieve this by using the delegation pattern. Basically you create an interface relative to the first adapter (you can put it inside the adapter class or outside depending on your coding style) and you require it as an argument inside the adapter constructor like this:
public class FruitItemAdapter extends RecyclerView.Adapter<FruitItemAdapter.viewHolder> {
private Delegate delegate;
ArrayList<FruitItem> fruitItems = new ArrayList<>();
private Context context;
public FruitItemAdapter(Delegate delegate, ArrayList<FruitItem> fruitItems, Context context) {
this.delegate = delegate;
this.fruitItems = fruitItems;
this.context = context;
notifyDataSetChanged();
}
...
interface Delegate {
public void passItem(FruitItem item);
}
}
As you can see the interface has the method you need, but there's no implementation yet.
In this class you can just pretend that your delegate works and do the magic for you, for example by setting a click listener on the root view of your item in onBindViewHolder that will call delegate.passItem(fruitItems.get(position)) on each click.
Let's move on to the fragment.
Here is the key part. The fragment must implement the interface we just created by overriding its methods. Like so:
class ExampleFragment extends Fragment implements FruitItemAdapter.Delegate {
...
#Override
public void passItem(FruitItem item) {
// here you pass the item in a list inside
// the shared preferences.
}
}
For your case the best way is to store your items in a database or in the shared preferences. We go with the shared preferences because is simpler, but keep in mind that shared preferences have limited memory capacity and you should use a database like Room instead.
Inside the override method you pass your item to a list stored in the shared preferences. Since your item is not a primitive object i suggest you to look at this answer that show how to store complex object as a string:
https://stackoverflow.com/a/18463758/18740763.
In your case the object that needs to be serialized is an Array or a List of objects.
Every time you need to put a new object in the list you need to follow these steps:
get the list from shared preferences
deserialize it
add the new item
serialize it again
put it back in the shared preferences under the same key
If you stored your items correctly now you should be able to access the shared list in every fragment or activity of your application. So simply access your list from the fragment that implements the second adapter, deserialize it, just addAll() the items the the adapter list and notifyDataSetChanged().

Android - How to send an ArrayList without using Intent?

I have an Activity and an Adapter Class. In my Adapter class, I have an ArrayList that I want to use in the Activity class. And Recycler view of Activity class is attached to the adapter class So, I cannot use intent to send it. So, Is there any other way I can access the ArrayList?

You can create your adapter as follow -
public class RecycleViewAdapter extends RecyclerView.Adapter<RecycleViewAdapter.CustomViewModel> {
private Context context;
private List<String> stringList;
public RecycleViewAdapter(Context context, List<String> stringList) {
this.context = context;
this.stringList = stringList;
}
#NonNull
#Override
public CustomViewModel onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
return new CustomViewModel(LayoutInflater.from(context).inflate(R.layout.recycle_view_item, parent, false));
}
#Override
public void onBindViewHolder(#NonNull CustomViewModel holder, int position) {
//put your code of binding of code
}
#Override
public int getItemCount() {
if (stringList!= null)
return stringList.size();
else
return 0;
}
//getter method of Adpater to return string
public List<String> getStringList() {
return stringList;
}
public class CustomViewModel extends RecyclerView.ViewHolder {
//your inner class code here
}
}
Now you can get List from your adapter as follows-
recycleViewAdapter.getStringList();
Happy coding !

In my opinion, you have three ways to do it:
move your ArrayList to ViewModel, then pass it to your adapter or use it in the activity.
place ArrayList just in the activity and pass it to the adapter.
create a getter in your adapter and use it in the activity.

I am not able to figure out how to pass Bundle in mapview.onCreate() in custom viewholder class

i have a generic viewholder class for recyclerview which uses MapView inside that row, and the viewholder class is extending my base viewholder abstract class which has populateData(TO to), i am initializing map in the constructor of my viewholder class and passing null to mapview.onCreate(null).
my classes are look like this
public class MyViewHolder extends BaseViewHolder implements OnReadyMapCallBack{
private MapView mapView;
public MyViewHolder(View view){
mapView = view.findViewById(R.id.map);
mapView.onCreate(null); //here i should pass Bundle instead
}
// this method is declared in parent class abstract class
#override
public void populateData(TO to){
mapView.getAsync(this);
}
public void onMapReady(GoogleMap googleMap) {
}
}

You trued this:
Bundle args = new Bundle();
args.putString("key",value);
mapView.onCreate(args);
?

Extend a class from an adapter class

In my application should be a lot of adapters similar to each other and I would like to know whether it is possible to make the interface or superclass to inherit from there and then, instead of writing 10 adapters, thanks !!
My adapter code
public class NewsAdapter extends RecyclerView.Adapter<NewsAdapter.NewsViewHolder> {
private List<News> newsList;
private Context ctx;
public NewsAdapter(List<News> newsList, Context ctx) {
this.newsList = newsList;
this.ctx = ctx;
}
static class NewsViewHolder extends RecyclerView.ViewHolder {
CardView cv;
TextView newsTitle;
TextView newsDescription;
ImageView newsImage;
TextView newsDate;
NewsViewHolder(View itemView) {
super(itemView);
cv = (CardView) itemView.findViewById(R.id.cvNews);
newsTitle = (TextView) itemView.findViewById(R.id.title_news);
newsDescription = (TextView) itemView.findViewById(R.id.description_news);
newsDate = (TextView) itemView.findViewById(R.id.date_news);
newsImage = (ImageView) itemView.findViewById(R.id.image_news);
}
}
#Override
public NewsViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.news_item, parent,
false);
return new NewsViewHolder(v);
}
#Override
public void onBindViewHolder(NewsViewHolder holder, int position) {
holder.newsTitle.setText(newsList.get(position).newsTitle);
holder.newsDescription.setText(newsList.get(position).newsDescription);
holder.newsDate.setText(newsList.get(position).newsDate);
Glide.with(ctx).load(Constants.SITE + newsList.get(position).newsImage)
.into(holder.newsImage);
}
#Override
public int getItemCount() {
return newsList.size();
}
#Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
super.onAttachedToRecyclerView(recyclerView);
}
}
All should reflect like this

it is possible to make the interface or superclass to inherit from
there and then, instead of writing 10 adapters
It is possible, but of course there must be something in common. For a start the dataset should be homogeneous. E.g. your items should all implement an interface, a contract between the item and the adapter itself. In your case, it could be
public interface DataItem {
String getTitle();
String getDescription();
String getDate();
String getImageUrl();
}
and instead of a private List<News> newsList;, you will have private List<? extends DataItem> newsList;. As I said, all your items have to implement that interface, and the properties have to be accessed through the getters

Interface value is always null

I am using custom recycler view and in adapter class i have implemented interface which is always null on button click. Here is my adapter class.
public class FeedListAdapter extends
RecyclerView.Adapter<AddtoCartHolder> {
private OnFeedItemClickListener onFeedItemClickListener;
public FeedListAdapter(Activity activity, ArrayList<CartItem> feedItems) {
this.activity = activity;
this.feedItems = feedItems;
this.filteredfeedItems = feedItems;
inflater = LayoutInflater.from(activity);
}
public void setOnFeedItemClickListener(OnFeedItemClickListener onFeedItemClickListener) {
this.onFeedItemClickListener = onFeedItemClickListener;
}
#Override
public AddtoCartHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(
R.layout.feed_item, parent, false);
AddtoCartHolder viewHolder = new AddtoCartHolder(v);
setupClickableViews(v, viewHolder);
return viewHolder;
}
#Override
public void onBindViewHolder(final AddtoCartHolder holder, int position) {
CartItem item = (CartItem) filteredfeedItems.get(position);
holder.price.setText((String.valueOf(item.getProductName()) + ""));
holder.location.setText((String.valueOf(item.getQuantity())) + "");
}
private void setupClickableViews(final View view, final AddtoCartHolder cellFeedViewHolder) {
cellFeedViewHolder.plus.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(onFeedItemClickListener !=null){
onFeedItemClickListener.onAddClick(v, cellFeedViewHolder.getAdapterPosition());
}
else{
Toast.makeText(activity, "Data is null", Toast.LENGTH_LONG).show();
}
}
});
}
public interface OnFeedItemClickListener {
void onAddClick(View v, int position);
}
#Override
public int getItemCount() {
return filteredfeedItems.size();
}
I am always getting null whenever clicking on button really down know why it is coming null...
Here is my fragment class which have implemented interface.
public class MyFragment extends Fragment implements FeedListAdapter.OnFeedItemClickListener{
// the method
#Override
public void onAddClick(View v, int position) {
// TODO Auto-generated method stub
Snackbar.make(clContent, "Product removed from cart!",
Snackbar.LENGTH_SHORT).show();
}

You must be instantiating a FeedListAdapter in your fragment correct buddy ???
Like using statement :
FeedListAdapter adapter = new FeedListAdapter(this.getActivity(),your_array_list)
After instantiating your adapter just call your adapter's setOnFeedItemClickListener with 'this' as argument :) That's all :)
adapter.setOnFeedItemClickListener(this)
Hope my answer helped you :) Happy coding buddy :)

By the looks of things your aren't setting your listener. Thus, onFeedItemClickListener is always null.
Also MyFragment isn't actually doing anything, you haven't inflated a view, overridden onCreateView(...), etc.
There's a few things that you could definitely change to improve your implementation. But to get your listener working:
Just get rid of MyFragment you don't appear to be using it properly.
Move your implements FeedListAdapter.OnFeedItemClickListener to your Activity. i.e. Make your Activity implement your OnFeedItemClickListener interface rather than MyFragment (which doesn't appear to be doing anything).
Make FeedListAdapter set the listener in its constructor:
public FeedListAdapter(Activity activity, ArrayList<CartItem> feedItems)
{
this.activity = activity;
// Assume we the activity implements OnFeedItemClickListener
setOnFeedItemClickListener((OnFeedItemClickListener)activity);
this.feedItems = feedItems;
this.filteredfeedItems = feedItems;
inflater = LayoutInflater.from(activity);
}
Please keep in mind that this is a pretty bad implementation and you can definitely improve on it but for the purpose of the question, it's sufficient.