Android RecyclerView : notifyDataSetChanged() IllegalStateException

Question

I'm trying to update the items of a recycleview using notifyDataSetChanged().

This is my onBindViewHolder() method in the recycleview adapter.

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

     //checkbox view listener
    viewHolder.getCheckbox().setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

            //update list items
            notifyDataSetChanged();
        }
    });
}

What I want to do is update the list items, after I check a checkbox. I get an illegal exception though: "Cannot call this method while RecyclerView is computing a layout or scrolling"

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)

I also used notifyItemChanged(), same exception. Any secret way to update to notify the adapter that something changed?

Answer 1

You should move method 'setOnCheckedChangeListener()' to ViewHolder which is inner class on your adapter.

onBindViewHolder() is not a method that initialize ViewHolder. This method is step of refresh each recycler item. When you call notifyDataSetChanged(), onBindViewHolder() will be called as the number of each item times.

So If you notifyDataSetChanged() put into onCheckChanged() and initialize checkBox in onBindViewHolder(), you will get IllegalStateException because of circular method call.

click checkbox -> onCheckedChanged() -> notifyDataSetChanged() -> onBindViewHolder() -> set checkbox -> onChecked...

Simply, you can fix this by put one flag into Adapter.

try this,

private boolean onBind;

public ViewHolder(View itemView) {
    super(itemView);
    mCheckBox = (CheckBox) itemView.findViewById(R.id.checkboxId);
    mCheckBox.setOnCheckChangeListener(this);
}

@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
    if(!onBind) {
        // your process when checkBox changed
        // ...

        notifyDataSetChanged();
    }
}

...

@Override
public void onBindViewHolder(YourAdapter.ViewHolder viewHolder, int position) {
    // process other views 
    // ...

    onBind = true;
    viewHolder.mCheckBox.setChecked(trueOrFalse);
    onBind = false;
}

Answer 2

You can just reset the previous listener before you make changes and you won't get this exception.

private CompoundButton.OnCheckedChangeListener checkedListener = new CompoundButton.OnCheckedChangeListener() {                      
                        @Override
                        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                            //Do your stuff
                    });;

    @Override
    public void onBindViewHolder(final ViewHolder holder, final int position) {
        holder.checkbox.setOnCheckedChangeListener(null);
        holder.checkbox.setChecked(condition);
        holder.checkbox.setOnCheckedChangeListener(checkedListener);
    }

Answer 3

Using a Handler for adding items and calling notify...() from this Handler fixed the issue for me.