View is null during onLoadMoreRequested ?

[AruLNadhaN]

I'm trying to add Pull to Load more for my RecyclerView using setOnLoadMoreListener. The App works fine when it is first loaded. But it raises a NPE with my Viewholder View when it hits the onLoadMoreRequested . How can I solve this ?

01-01 12:24:13.576 14246-14246/? E/AndroidRuntime: FATAL EXCEPTION: main
                                                   Process: me.aruln PID: 14246
                                                   java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
                                                       at me.arulnadhaies.BrowseAdapter$ShotViewHolder.<init>(BrowseAdapter.java:161)
                                                       at me.arulnadwseAdapter.createBaseViewHolder(BrowseAdapter.java:50)
                                                       at me.arulnadhties.BrowseAdapter.createBaseViewHolder(BrowseAdapter.java:23)
                                                       at com.chad.library.adapter.base.BaseQuickAdapter.getLoadingView(BaseQuickAdapter.java:548)
                                                       at com.chad.library.adapter.base.BaseQuickAdapter.onCreateViewHolder(BaseQuickAdapter.java:527)
                                                       at com.chad.library.adapter.base.BaseQuickAdapter.onCreateViewHolder(BaseQuickAdapter.java:57)
                                                       at android.support.v7.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:6290)
                                                       at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5478)
                                                       at android.support.v7.widget.GapWorker.prefetchPositionWithDeadline(GapWorker.java:270)
                                                       at android.support.v7.widget.GapWorker.flushTaskWithDeadline(GapWorker.java:324)
                                                       at android.support.v7.widget.GapWorker.flushTasksWithDeadline(GapWorker.java:337)
                                                       at android.support.v7.widget.GapWorker.prefetch(GapWorker.java:344)
                                                       at android.support.v7.widget.GapWorker.run(GapWorker.java:370)
                                                       at android.os.Handler.handleCallback(Handler.java:739)
                                                       at android.os.Handler.dispatchMessage(Handler.java:95)
                                                       at android.os.Looper.loop(Looper.java:135)
                                                       at android.app.ActivityThread.main(ActivityThread.java:5292)
                                                       at java.lang.reflect.Method.invoke(Native Method)
                                                       at java.lang.reflect.Method.invoke(Method.java:372)
                                                       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904)
                                                       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:699)

Adapter Code

public void setClickListener(ClickListener clickListener) {
        mClickListener = clickListener;
    }

   @Override
    protected ShotViewHolder createBaseViewHolder(View view) {
        return new ShotViewHolder(view);
    }

 @Override
    protected void convert(ShotViewHolder shotViewHolder, Items item) {

            shotViewHolder.mItem = item;
            shotViewHolder.prodName.setText(item.getName());
            shotViewHolder.prodPrice.setText( String.valueOf(item.getPrice()));
            shotViewHolder.prodUnit.setText(item.getUnit());
            if (item.isSelected()) {
                shotViewHolder.mAddCart.setVisibility(View.GONE);
                shotViewHolder.mPickerView.setVisibility(VISIBLE);
                shotViewHolder.mPicker.setValue(item.getAddedCount());
            } else {
                shotViewHolder.mPickerView.setVisibility(View.GONE);
            }
            Glide.with(shotViewHolder.itemView.getContext()).load(item.getImage())
                    .diskCacheStrategy(DiskCacheStrategy.SOURCE).into(shotViewHolder.prodImage);

    }

public class ShotViewHolder extends BaseViewHolder {
        ImageView prodImage;
        TextView prodPrice;
        TextView prodName;
        TextView prodUnit;
        View viewFooter;
        View mAddCart;
        View mPickerView;
        IncDecImageButton mPicker;
        Items mItem;

        public ShotViewHolder(View itemView) {
            super(itemView);
            prodImage= (ImageView)itemView.findViewById(R.id.image_shot);
            prodPrice= (TextView)itemView.findViewById(R.id.text_price);
            prodName= (TextView)itemView.findViewById(R.id.text_title);
            prodUnit= (TextView)itemView.findViewById(R.id.text_unit);
            viewFooter= (View)itemView.findViewById(R.id.layout_footer);
            mPickerView= (View)itemView.findViewById(R.id.quantity_picker);
            mPicker= (IncDecImageButton)itemView.findViewById(R.id.incdec);
            mAddCart= (View)itemView.findViewById(R.id.add_cart);
            itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if (mClickListener != null) {
                        mClickListener.onShotClick(mItem);
                    }
                }
            });
            mAddCart.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if (mClickListener != null) {
                        mItem.setSelected(true);
                        mAddCart.setVisibility(View.GONE);
                        mPickerView.setVisibility(VISIBLE);
                        mClickListener.onCartAdd(mItem);
                    }
                }
            });
            mPicker.setOnValueChangeListener(new IncDecImageButton.OnValueChangeListener() {
                @Override
                public void onValueChange(IncDecImageButton view, float oldValue, float newValue) {
                    mItem.setAddedCount(newValue);
                    if(newValue == 0.0){
                        mItem.setSelected(false);
                        mClickListener.onCartRemove(mItem);
                        mPickerView.setVisibility(View.GONE);
                        mAddCart.setVisibility(VISIBLE);
                    }
                }
            });
        }
    }

Activity Code

@Override
    public void onLoadMoreRequested() {
        Timber.d("Lazy -> Method!"+ mCurrentCounter);
                if (mCurrentCounter >= TOTAL_COUNTER) {
                    Timber.d("Lazy -> loadMoreEnd!");
//                    mBrowseAdapter.loadMoreEnd();//default visible
                    mBrowseAdapter.loadMoreEnd(false);//true is gone,false is visible
                } else {
                    if (isErr) {
                        Timber.d("Lazy -> addData!");
                        mBrowseAdapter.addData(mBrowsePresenter.loadItems());
                        mCurrentCounter = mBrowseAdapter.getData().size();
                        mBrowseAdapter.loadMoreComplete();
                    } else {
                        isErr = true;
                        Timber.d("Lazy -> Error");
                        mBrowseAdapter.loadMoreFail();
                    }
                }
    }

[1109993488]

You should override onCreateDefViewHolder, call setOnClickListener and setOnValueChangeListener in onCreateDefViewHolder

[AruLNadhaN]

As you suggested, I tried to call setOnClickListener by overriding onCreateDefViewHolder. But I had some issues to intialize mItem & get itemView. How can i get them ?

@Override
 protected ShotViewHolder onCreateDefViewHolder(ViewGroup parent, int viewType) {

     IncDecImageButton mPicker;
     View mAddCart;
     Items mItem;
     View mPickerView;

     mPickerView = (View) parent.findViewById(R.id.quantity_picker);
     mPicker = (IncDecImageButton) parent.findViewById(R.id.incdec);
     mAddCart = (View) parent.findViewById(R.id.add_cart);

     itemView.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
             if (mClickListener != null) {
                 mClickListener.onShotClick(mItem);
             }
         }
     });
     
     mAddCart.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
             if (mClickListener != null) {
                 mItem.setSelected(true);
                 mAddCart.setVisibility(View.GONE);
                 mPickerView.setVisibility(VISIBLE);
                 mClickListener.onCartAdd(mItem);
             }
         }
     });

     mPicker.setOnValueChangeListener(new IncDecImageButton.OnValueChangeListener() {
         @Override
         public void onValueChange(IncDecImageButton view, float oldValue, float newValue) {
             mItem.setAddedCount(newValue);
             if(newValue == 0.0){
                 mItem.setSelected(false);
                 mClickListener.onCartRemove(mItem);
                 mPickerView.setVisibility(View.GONE);
                 mAddCart.setVisibility(VISIBLE);
             }
         }
     });
     return super.onCreateDefViewHolder(parent, viewType);
 }

[1109993488]

ShotViewHolder holder = super.onCreateDefViewHolder(parent, viewType);

//holder.itemView
//holder.getView

return holder;

[1109993488]

Depending on your needs, you should override the convert method, setListener in the convert method, without rewriting the onCreateDefViewHolder

[AruLNadhaN]

Thanks! It worked...