findViewById in RecyclerView ViewHolder throws NullPointerExcpetion

Question

I'm trying to display data with a RecyclerView. I'm not too sure why it keep crashing with a NullPointerException. My theory is that it is trying to find the TextView before the view itself has been created.

However, with the way my constructor is, it shouldn't be doing that.

Been at this for a couple hours now. Any help would be greatly appreciated.

My XML file:

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    >
    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_margin="10dp"
        >

        <TextView
            android:id="@+id/recycler_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="name"
            android:textColor="@color/icons" />

        <TextView
            android:id="@+id/recycler_price"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:layout_marginRight="18dp"
            android:text="price"
            android:textColor="@color/icons"
            android:textStyle="bold"/>
        <TextView
            android:id="@+id/recycler_date"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="date"
            android:layout_below="@+id/recycler_name"
            android:textColor="@color/icons"
            android:textStyle="italic"
            android:paddingTop="3dp"
            />

    </RelativeLayout>
</android.support.v7.widget.CardView>

RecyclerView Adapter:

public class ExpenseAdapter extends RecyclerView.Adapter<ExpenseAdapter.ItemViewHolder> {
    private ArrayList<Item> mExpenseList;

    public static class ItemViewHolder extends RecyclerView.ViewHolder {
        public TextView frag_name;
        public TextView frag_price;
        public TextView frag_date;


        public ItemViewHolder(@NonNull View itemView) {
            super(itemView);
            frag_name.findViewById(R.id.recycler_name);
            frag_price.findViewById(R.id.recycler_price);
            frag_date.findViewById(R.id.recycler_date);
        }
    }

    @NonNull
    @Override
    public ItemViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int i) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.expense, parent, false);
        ItemViewHolder viewHolder = new ItemViewHolder(v);
        return viewHolder;
    }

    // constructor to receive list of expenses for recycler view to process
    public ExpenseAdapter(ArrayList<Item> expenseList) {
         mExpenseList = expenseList;
    }

    @Override
    public void onBindViewHolder(@NonNull ItemViewHolder itemViewHolder, int i) {
        Item currItem = mExpenseList.get(i);

        itemViewHolder.frag_name.setText(currItem.getName());
        itemViewHolder.frag_price.setText(Integer.toString(currItem.getPrice()));
        itemViewHolder.frag_date.setText(currItem.getDatePurhase());
    }

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

`frag_name.findViewById(R.id.recycler_name);` – That's not how to do that there. It would be `frag_name = itemView.findViewById(R.id.recycler_name);`, and similarly for the others. — Mike M., Jan 17 '19 at 19:27
`TextView.findViewById()` is a) non-sense and b) `null`... try `itemViewHolder.findViewById()` instead. — Martin Zeitler, Jan 17 '19 at 19:28

score 0 · Accepted Answer · answered Jan 17 '19 at 19:27

You need to initialize views in your ItemViewHolder before using them. Right now frag_name.findViewById(R.id.recycler_name) will throw NullPointerException cause your trying to use wrong view to findViewById().

Use this code:

public ItemViewHolder(@NonNull View itemView) {
        super(itemView);
        frag_name = itemView.findViewById(R.id.recycler_name);
        frag_price = itemView.findViewById(R.id.recycler_price);
        frag_date = itemView.findViewById(R.id.recycler_date);
    }

Thank you. Now i feel dumb for asking this questions – igohardinmath Jan 17 '19 at 19:40 — igohardinmath, Jan 17 '19 at 19:40

findViewById in RecyclerView ViewHolder throws NullPointerExcpetion

1 Answers1