Problem : java.lang.NullPointerException: Argument must not be null

Question

I have a problem in this line : public class ShowAllAdapter extends RecyclerView.Adapter<ShowAllAdapter.ViewHolder> {

and in this line : Glide.with(context).load(list.get(position).getImg_url()).into(holder.mItemImage); when i run the app and click something the app keep stopping... but i can still run the app..

public class ShowAllAdapter extends RecyclerView.Adapter<ShowAllAdapter.ViewHolder> {

    private Context context;
    private List<ShowAllModel> list;

    public ShowAllAdapter(Context context, List<ShowAllModel> list) {
        this.context = context;
        this.list = list;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        return new ViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.show_all_item,parent,false));
    }

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

        Glide.with(context).load(list.get(position).getImg_url()).into(holder.mItemImage);
        holder.mCost.setText(String.valueOf(list.get(position).getPrice()));
        holder.mName.setText(list.get(position).getName());

    }

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

    public class ViewHolder extends RecyclerView.ViewHolder {

        private ImageView mItemImage;
        private TextView mCost;
        private TextView mName;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);
        }
    }
}

The Error:

**2022-01-19 17:30:08.898 1627-1627/com.example.ichibananimerch E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.ichibananimerch, PID: 1627
    java.lang.NullPointerException: Argument must not be null
        at com.bumptech.glide.util.Preconditions.checkNotNull(Preconditions.java:29)
        at com.bumptech.glide.util.Preconditions.checkNotNull(Preconditions.java:23)
        at com.bumptech.glide.RequestBuilder.into(RequestBuilder.java:768)
        at com.example.ichibananimerch.adapters.ShowAllAdapter.onBindViewHolder(ShowAllAdapter.java:38)
        at com.example.ichibananimerch.adapters.ShowAllAdapter.onBindViewHolder(ShowAllAdapter.java:19)
        at androidx.recyclerview.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:7065)
        at androidx.recyclerview.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:7107)
        at androidx.recyclerview.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:6012)
        at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6279)
        at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6118)
        at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6114)
        at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2303)
        at androidx.recyclerview.widget.GridLayoutManager.layoutChunk(GridLayoutManager.java:561)
        at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1587)
        at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:665)
        at androidx.recyclerview.widget.GridLayoutManager.onLayoutChildren(GridLayoutManager.java:170)
        at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:4134)
        at androidx.recyclerview.widget.RecyclerView.onMeasure(RecyclerView.java:3540)
        at android.view.View.measure(View.java:19734)
        at androidx.constraintlayout.widget.ConstraintLayout$Measurer.measure(ConstraintLayout.java:811)
        at androidx.constraintlayout.core.widgets.analyzer.BasicMeasure.measure(BasicMeasure.java:466)
        at androidx.constraintlayout.core.widgets.analyzer.BasicMeasure.measureChildren(BasicMeasure.java:134)
        at androidx.constraintlayout.core.widgets.analyzer.BasicMeasure.solverMeasure(BasicMeasure.java:278)
        at androidx.constraintlayout.core.widgets.ConstraintWidgetContainer.measure(ConstraintWidgetContainer.java:120)
        at androidx.constraintlayout.widget.ConstraintLayout.resolveSystem(ConstraintLayout.java:1594)
        at androidx.constraintlayout.widget.ConstraintLayout.onMeasure(ConstraintLayout.java:1708)
        at android.view.View.measure(View.java:19734)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6120)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at androidx.appcompat.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:145)
        at android.view.View.measure(View.java:19734)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6120)
        at androidx.appcompat.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:496)
        at android.view.View.measure(View.java:19734)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6120)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at android.view.View.measure(View.java:19734)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6120)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1464)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:758)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:640)
        at android.view.View.measure(View.java:19734)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6120)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at com.android.internal.policy.DecorView.onMeasure(DecorView.java:687)
        at android.view.View.measure(View.java:19734)
        at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2271)
        at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1358) 2022-01-19 17:30:08.898 1627-1627/com.example.ichibananimerch E/AndroidRuntime:     at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1607)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1246)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6301)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:871)
        at android.view.Choreographer.doCallbacks(Choreographer.java:683)
        at android.view.Choreographer.doFrame(Choreographer.java:619)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:857)
        at android.os.Handler.handleCallback(Handler.java:751)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6077)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)**

Answer 1

You forgot to define interface elements you should use itemView.findViewById();

    public class ViewHolder extends RecyclerView.ViewHolder {

    private ImageView mItemImage;
    private TextView mCost;
    private TextView mName;

    public ViewHolder(@NonNull View itemView) {
        super(itemView);

        //HERE!!!!!!!
    }
}