Single selection in RecyclerView

Question

I know there are no default selection methods in the RecyclerView class, but I have tried in the following way:

public void onBindViewHolder(ViewHolder holder, final int position) {     holder.mTextView.setText(fonts.get(position).getName());     holder.checkBox.setChecked(fonts.get(position).isSelected());      holder.checkBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {         @Override         public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {             if(isChecked) {                 for (int i = 0; i < fonts.size(); i++) {                     fonts.get(i).setSelected(false);                 }                 fonts.get(position).setSelected(isChecked);             }         }     }); } 

While trying this code, I got the expected output, but not completely.

I will explain this with images.

By default, the first item is selected from my adapter.

Then I select the 2nd, then the 3rd, then the 4th and finally the 5th one.

Here only the 5th should be selected, but all five are getting selected.

If I scroll the list to the bottom and come again to the top, I get what I expect.

How can I overcome this issue? And sometimes if I scroll the list very fast, some other item gets selected. How can I overcome this problem too?

While I was trying to use notifyDataSetChanged() after fonts.get(position).setSelected(isChecked);, I got the following exception:

java.lang.IllegalStateException: Cannot call this method while RecyclerView is computing a layout or scrolling         at android.support.v7.widget.RecyclerView.assertNotInLayoutOrScroll(RecyclerView.java:1462)         at android.support.v7.widget.RecyclerView$RecyclerViewDataObserver.onChanged(RecyclerView.java:2982)         at android.support.v7.widget.RecyclerView$AdapterDataObservable.notifyChanged(RecyclerView.java:7493)         at android.support.v7.widget.RecyclerView$Adapter.notifyDataSetChanged(RecyclerView.java:4338)         at com.app.myapp.screens.RecycleAdapter.onRowSelect(RecycleAdapter.java:111) 

Answer 1

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);            }        });     } }