Single Selection in Recyclerview

Single selection in RecyclerView

The solution for the issue:

public class yourRecyclerViewAdapter extends RecyclerView.Adapter<yourRecyclerViewAdapter.yourViewHolder> {

    private static CheckBox lastChecked = null;
    private static int lastCheckedPos = 0;


    public void onBindViewHolder(ViewHolder holder, final int position) {
    
        holder.mTextView.setText(fonts.get(position).getName());
        holder.checkBox.setChecked(fonts.get(position).isSelected());
        holder.checkBox.setTag(new Integer(position));

        //for default check in first item
        if(position == 0 && fonts.get(0).isSelected() && holder.checkBox.isChecked())
        {
           lastChecked = holder.checkBox;
           lastCheckedPos = 0;
        }
           
        holder.checkBox.setOnClickListener(new View.OnClickListener() 
        {
            @Override
            public void onClick(View v) 
            {
               CheckBox cb = (CheckBox)v;
               int clickedPos = ((Integer)cb.getTag()).intValue(); 

               if(cb.isChecked())
               {
                  if(lastChecked != null)
                  {
                      lastChecked.setChecked(false);
                      fonts.get(lastCheckedPos).setSelected(false);
                  }                       
                 
                  lastChecked = cb;
                  lastCheckedPos = clickedPos;
              }
              else
                 lastChecked = null;

              fonts.get(clickedPos).setSelected(cb.isChecked);
           }
       });
    }
}

Recyclerview Single Item Selector

This is my sample solution:

public class VisaTypeAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    Context context;
    private List<VisaType> visaTypeList;

    int selected_position;


    public VisaTypeAdapter(Context context, List<VisaType> visaTypeList) {
        this.context = context;
        this.visaTypeList = visaTypeList;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.visa_type_row, parent, false);
        return new jp.workjapan.adapters.VisaTypeAdapter.ViewHolder(view);

    }

    @Override
    public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int position) {
        final VisaType a = visaTypeList.get(position);
        final jp.workjapan.adapters.VisaTypeAdapter.ViewHolder viewHolder = (jp.workjapan.adapters.VisaTypeAdapter.ViewHolder) holder;
        viewHolder.visa_eng.setText(a.getName_en());
        viewHolder.visa_jp.setText(a.getName_jp());


        final long id = a.getId();
        if (id == AppSingleTon.visaType) {
            viewHolder.visa_layout.setSelected(true);
        } else {
            viewHolder.visa_layout.setSelected(false);
        }

        if (position == selected_position) {
            viewHolder.visa_layout.setSelected(true);
        } else {
            viewHolder.visa_layout.setSelected(false);
        }

        viewHolder.visa_layout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                selected_position = getAdapterPosition();
                notifyDataSetChanged();
            }
        });

    }

}

Hope it helps you...
Thanks

Single Selection RecyclerView TextView

I will show you how to achieve what you are looking for using a simple example to show a list of strings.

My view to represent a item in RecyclerView view will be test_cell_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    android:id="@+id/holder_background"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:id="@+id/item_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textColor="@android:color/white"/>

</LinearLayout>

And I created an adapter extending RecyclerView.Adapter

import android.content.Context;
import android.graphics.Color;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;

import java.util.List;


public class TestAdapter extends RecyclerView.Adapter<TestAdapter.ViewHolder> {

    private int selectedPos = 0;

    private OnItemClickListener listener;

    public interface OnItemClickListener {
        void onItemClick(View viewItem, int position);
    }

    public void setOnItemClickListener(OnItemClickListener listener) {
        this.listener = listener;
    }

    public class ViewHolder extends RecyclerView.ViewHolder {
        LinearLayout background;
        TextView itemText;

        ViewHolder(final View viewItem) {
            super(viewItem);
            background = (LinearLayout) viewItem.findViewById(R.id.holder_background);
            itemText = (TextView) viewItem.findViewById(R.id.item_text);

            viewItem.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    // Triggers click upwards to the adapter on click
                    if (listener != null) {
                        int position = getAdapterPosition();
                        if (position != RecyclerView.NO_POSITION) {
                            listener.onItemClick(viewItem, position);
                            notifyItemChanged(selectedPos);
                            selectedPos =getAdapterPosition();
                            notifyItemChanged(selectedPos);
                        }
                    }
                }
            });
        }
        public void changeToSelect(int colorBackground) {
            background.setBackgroundColor(colorBackground);
        }
    }

    private List<String> list;
    private Context context;

    public TestAdapter(Context context, List<String> list) {
        this.list = list;
        this.context= context;
    }

    @Override
    public TestAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        Context context = parent.getContext();
        LayoutInflater inflater = LayoutInflater.from(context);
        View itemView = inflater.inflate(R.layout.test_cell_item, parent, false);
        ViewHolder itemViewHolder = new ViewHolder(itemView);
        return itemViewHolder;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        holder.changeToSelect(selectedPos == position ? Color.parseColor("#ca3854") : Color.BLACK);
        TextView filterText = holder.itemText;
        filterText.setTextSize(30);
        filterText.setText(list.get(position));
    }

    @Override
    public int getItemCount() {
        return list.size();
    }
}

Here you can see that i have created a Interface to use as the OnItemClickListener. I have defined a global variable to hold the currently selected item position. When everytime a view is clicked i change the selected item position and notifychanges to the adapter so that it can update its view with changes. OnBindViewHolder method i change the color of the background to select color if the position is currently selected position and to black if not.

In activity i used adapter like this,

        RecyclerView view = findViewById(R.id.view);
        ArrayList<String> list = new ArrayList<>();
        for(int i = 100; i < 150; i++) {
            list.add(Integer.toString(i));
        }
        TestAdapter adaptor = new TestAdapter(this, list);
        adaptor.setOnItemClickListener(new TestAdapter.OnItemClickListener() {
            @Override
            public void onItemClick(View viewItem, int position) {
                //Your item click code
            }
        });
        view.setAdapter(adaptor);
        LinearLayoutManager liveImageLayoutManager = new LinearLayoutManager(getApplicationContext());
        liveImageLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        view.setLayoutManager(liveImageLayoutManager);

I hope you can take a look at this and adapt how it is done to your code.

How to make single selection work in a nested RecyclerView

UPDATE: Managed to come up with a solution myself, although 100% sure, not the best approach.

First of all, implement Greenrobots EventBus:

implementation 'org.greenrobot:eventbus:3.1.1'

Now in the Activity where you hold both RecyclerViews register the Event listener:

 @Override
    protected void onStart() {
        super.onStart();
        EventBus.getDefault().register(this);
    }

and subscribe 2 methods. One for Parent Events and one for Children Events. This methods will trigger every time an item is selected!

    @Subscribe(threadMode = ThreadMode.MAIN)
    public void onParentEventClicked(ParentAdapter.ParentEvent event) {
// to access the inner adapter here you must set it to public in the ParentAdapter(public ChildAdapter adapter;)
        adapter.adapter.deSelectChild();
    }

    @Subscribe(threadMode = ThreadMode.MAIN)
    public void onChildEventClicked(ChildAdapter.ChildEvent event) {
// normal ParentAdapter reference(ParentAdapter adapter;)
        adapter.deSelectParent();
    }

Inside your ParentAdapter create a method to deselect all parent items and a static class to fire the event:

public void deSelectParent()
    {
        for (int i=0;i<data.size();i++)
        {
            data.get(i).setSelected(false);
        }
        notifyDataSetChanged();
    }

public static class ParentEvent {
        View view;
        int position;
    }

Inside your ChildAdapter create a method to deselect all child items and a static class to fire the event:

public void deSelectChild()
    {
        for (int i=0;i<data.size();i++)
        {
            datachild.get(i).setSelected(false);
        }
        notifyDataSetChanged();
    }

public static class ChildEvent {
        View view;
        int position;
    }

now in both Parent and Child onBindViewHolders, you need similar logic for your models:

if (item.isSelected()) {
                holder.yourbutton.setChecked(true);
            } else {
                holder.yourbutton.setChecked(false);
            }

holder.yourbutton.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    ParentEvent event = new ParentEvent();
                    event.view = holder.yourbutton;
                    event.position = position;
                    EventBus.getDefault().post(event);
                    if (holder.yourbutton.isChecked()) {
                        for (int i = 0; i < data.size(); i++) {
                            data.get(i).setSelected(false);
                        }
                        data.get(position).setSelected(true);
                    } else {
                        data.get(position).setSelected(false);
                    }
                    notifyDataSetChanged();
                }
            });

And thats pretty much it, every click on a ParentItem will trigger the deselect method for ChildAdapter and vice-versa.
Due to the high usage of notifyDataSetChanged() I recommend using this line to get rid of the blinking:

 recycler_view_parent.setItemAnimator(null);

Any problems let me know!

How can I select only one checkbox in Recyclerview and notifydataset changed

this is the best code!
notice onBindViewHolder

public class SupportSchoolIdAdapter extends RecyclerView.Adapter<SupportSchoolIdAdapter.ViewHolder > {

private Context context;
ArrayList<SupportSchoolIdModel> supportSchoolIdModels;
private int selectedPosition = 0;
private ArrayList<Integer> selectCheck = new ArrayList<>();

public SupportSchoolIdAdapter (Context context, ArrayList<SupportSchoolIdModel> supportSchoolIdModels) {
    this.context = context;
    this.supportSchoolIdModels = supportSchoolIdModels;

//initilize selectCheck 
    for (int i = 0; i < supportSchoolIdModels.size(); i++) {
        selectCheck.add(0);
    }

}

@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
     View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.support_school_item, parent, false);
     return new ViewHolder(v);
}

@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int position) {

    if (selectCheck.get(position) == 1) {
        holder.checkbox.setChecked(true);
    } else {
        holder.checkbox.setChecked(false);
    }

    holder.checkbox.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            for(int k=0; k<selectCheck.size(); k++) {
                if(k==position) {
                    selectCheck.set(k,1);
                } else {
                    selectCheck.set(k,0);
                }
            }
            notifyDataSetChanged();

        }
    });
    holder.checkbox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

            if(isChecked==true){
                //Do whatever you want to do with selected value
            }
        }
    });

}

@Override
public int getItemCount() {
    return supportSchoolIdModels== null? 0: supportSchoolIdModels.size();
}

class ViewHolder extends RecyclerView.ViewHolde {

    CheckBox checkbox;

    public ViewHolder(View v) {
        super(v);
        checkbox = (CheckBox) v.findViewById(R.id.checkbox);          
    }

}

}

Single Selection item with Recycler Grid View

Here is the solution for your requirement

public class AdapterClass extends RecyclerView.Adapter<AdapterClass.ViewHolder> {
        private int selected_position = -1;

        @Override
        public void onBindViewHolder(AdapterClass.ViewHolder holder, final int position) {
            if (selected_position == position) {
                // do your stuff here like
                //Change selected item background color and Show sub item views

            } else {
                  // do your stuff here like
                  //Change  unselected item background color and Hide sub item views
            }
  // rest of the code here

    holder.linelayout.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View view) {
              if(selected_position==position){
                        selected_position=-1;
                        notifyDataSetChanged();
                        return;
                    }
                    selected_position = position;
                    notifyDataSetChanged();

            }
        });

    //rest of the code here

     }


}

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