Arthur Arthur - 5 months ago 1079
Android Question

Recycleview notifyDataSetChanged() IllegalStateException

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

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;
}

I hope that this helps you

Lastly, I'm sorry because of my poor english.