android - 在我的 Recyclerview 上点击 RecyclerAdapter

Question

我试图在我的 RecyclerAdapter 中创建响应式点击事件。我无法理解其背后的逻辑，因为我的数据是由 API 自动创建的，因此我的列表中有一些按钮，我希望通过单击它来获得响应。

这是我的代码:

我的适配器类:

    public class EppViewCartAdapter extends RecyclerView.Adapter<EppViewCartAdapter.MyViewHolder> {
        View itemView;
        ImageView add,less;
        private List<EppViewCartDetails> orderData;

        public class MyViewHolder extends RecyclerView.ViewHolder {
            TextView subject,category,brand,neww,newd,old,discount,count,color;
            ImageView image;


            public MyViewHolder(View view) {
                super(view);
                subject=view.findViewById(R.id.view_cart_item_subject);
                category=view.findViewById(R.id.view_cart_item_category);
                brand=view.findViewById(R.id.view_cart_item_brand);
                neww=view.findViewById(R.id.view_cart_item_neww);
                old=view.findViewById(R.id.view_cart_item_old);
                discount=view.findViewById(R.id.view_cart_item_discount);
                newd=view.findViewById(R.id.view_cart_item_new_depends_count);
                count=view.findViewById(R.id.view_cart_item_count);
                image=view.findViewById(R.id.view_cart_item_image);
                add=itemView.findViewById(R.id.view_btn_add);
                less=itemView.findViewById(R.id.view_btn_less);

            }
        }

        public EppViewCartAdapter(List<EppViewCartDetails> preorderList) {
            this.orderData = preorderList;
        }

        @Override
        public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            itemView = LayoutInflater.from(parent.getContext())
                    .inflate(R.layout.view_cart_card_view, parent, false);

            //TODO: I was trying to make a set onlcick  listener here but it has errors.
            add.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Toast.makeText(itemView.getContext(), "Add Click response properly.", Toast.LENGTH_SHORT).show();
                }
            });


            return new MyViewHolder(itemView);
        }

        @Override
        public void onBindViewHolder(MyViewHolder holder, final int position) {
            EppViewCartDetails data= orderData.get(position);

            double amount = Double.parseDouble(data.getCount())*Double.parseDouble(data.getNeww());
            DecimalFormat formatter = new DecimalFormat("#,###.00");

            holder.subject.setText(data.getSubject());
            holder.category.setText(data.getCategory());
            holder.brand.setText(data.getBrand());
            holder.neww.setText("₱ "+formatter.format(amount));
            holder.newd.setText(data.getNewd());
            holder.old.setText(data.getOld());
            holder.old.setPaintFlags(holder.old.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
            holder.discount.setText(data.getDiscount());
            holder.count.setText(data.getCount());



            Picasso.with(itemView.getContext()).load("https://eppteststorage.blob.core.windows.net/images/"+data.getImage()).placeholder(R.drawable.small_logo).into(holder.image, new com.squareup.picasso.Callback() {
                        @Override
                        public void onSuccess() {
                            Log.e("tae tae"," PAkultie");
                        }

                        @Override
                        public void onError() {
                        }
                    }
            );


        }


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

    }

我在尝试我的 OnclickEvent 时出错:(在我的//TODO:)

   Process: eppmobile.intellismart.com.EPP, PID: 18675
    java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
        at eppmobile.intellismart.com.EPP.ViewCart.EppViewCartAdapter.onCreateViewHolder(EppViewCartAdapter.java:58)
        at eppmobile.intellismart.com.EPP.ViewCart.EppViewCartAdapter.onCreateViewHolder(EppViewCartAdapter.java:22)
        at android.support.v7.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:6794)
        at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5975)
        at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5858)
        at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5854)
        at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2230)
        at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1557)

我的 Activity 类:

    public class EppViewCart extends Fragment {
        View inflatedView = null;
        EppViewCartDetails items;
        private List<EppViewCartDetails> dataitems = new ArrayList<>();

        @Nullable
        @Override
        public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
            inflatedView = inflater.inflate(R.layout.fragment_epp_view_cart, container, false);
            retriveSQLITE();


            return inflatedView;
        }

        private void retriveSQLITE() {
            SqLiteDB sql = new SqLiteDB(getContext());
            SQLiteDatabase db = sql.getWritableDatabase();
            Cursor c = sql.retrieveAddToCart(db);
            ArrayList<AddToCartModel> get = new ArrayList<>();
            while (c.moveToNext()) {
                final AddToCartModel details = new AddToCartModel();
                details.setID(c.getString(c.getColumnIndexOrThrow("ID")));
                details.setDateTime(c.getString(c.getColumnIndexOrThrow("DateTime")));
                details.setID_ProductMasterListV(c.getString(c.getColumnIndexOrThrow("ID_ProductMasterListV")));
                details.setImageFile(c.getString(c.getColumnIndexOrThrow("ImageFile")));
                details.setOrdered(c.getString(c.getColumnIndexOrThrow("Ordered")));
                get.add(details);

                APICaller service = EppMainFragmentPropertyClient.getRetrofit().create(APICaller.class);
                View_Response gets = new View_Response("1", details.getID(), details.getID_ProductMasterListV());
                Call<List<View_Data_Properties>> call = service.getView(gets);
                call.enqueue(new Callback<List<View_Data_Properties>>() {
                    @Override
                    public void onResponse(Call<List<View_Data_Properties>> call, Response<List<View_Data_Properties>> response) {

                        //Discount
                        String q = String.format("%.2f", Double.parseDouble(response.body().get(0).getLess()));
                        long l = Math.round(Double.parseDouble(q));
                        String percent = l + "%";

                        double amount = Double.parseDouble(response.body().get(0).getNewPrice());
                        DecimalFormat formatter = new DecimalFormat("#,###.00");

                        double amount2 = Double.parseDouble(response.body().get(0).getSRP());
                        DecimalFormat formatter2 = new DecimalFormat("#,###.00");

                        items = new EppViewCartDetails(
                                response.body().get(0).getID(),
                                response.body().get(0).getName(),
                                response.body().get(0).getCategory(),
                                response.body().get(0).getProductsBrand(),
                                response.body().get(0).getNewPrice(),
                                "₱ " + formatter.format(amount),
                                "₱ " + formatter2.format(amount2),
                                "-" + percent,
                                details.getOrdered(), response.body().get(0).getHexValue(),
                                response.body().get(0).getImageFile());
                        dataitems.add(items);

                        prepareItems();
                    }

                    @Override
                    public void onFailure(Call<List<View_Data_Properties>> call, Throwable t) {

                    }
                });


            }

        }

        private void prepareItems() {
            //Items
            LinearLayoutManager layoutManager = new LinearLayoutManager(getContext(), LinearLayoutManager.VERTICAL, false);
            RecyclerView recyclerView = inflatedView.findViewById(R.id.view_cart_recycler);
            recyclerView.setLayoutManager(layoutManager);
            EppViewCartAdapter mAdapter = new EppViewCartAdapter(dataitems);
            recyclerView.setAdapter(mAdapter);

        }

    }

我的卡片 View :

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

<RelativeLayout
    android:layout_marginTop="8dp"
    android:layout_marginLeft="5dp"
    android:layout_marginRight="5dp"
    android:background="@drawable/radius_all_two"
    android:layout_width="match_parent"
    android:layout_height="190dp">

    <ImageView
        android:layout_width="110dp"
        android:layout_height="120dp"
        android:src="@drawable/bestseller"
        android:id="@+id/view_cart_item_image"
        android:layout_centerVertical="true"
        android:layout_marginLeft="15dp"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="JBL- Grip 100"
        android:id="@+id/view_cart_item_subject"
        android:textColor="#000"
        android:textSize="14dp"
        android:layout_marginLeft="140dp"
        android:layout_marginTop="25dp"/>

    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_marginTop="15dp"
        android:layout_height="wrap_content">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Category"
        android:textColor="#089bcc"
        android:textSize="11dp"
        android:layout_marginLeft="140dp"
        android:layout_marginTop="48dp"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Headphones"
        android:id="@+id/view_cart_item_category"
        android:textSize="11dp"
        android:layout_marginLeft="190dp"
        android:layout_marginTop="48dp"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Brand"
        android:textColor="#089bcc"
        android:textSize="11dp"
        android:layout_marginLeft="140dp"
        android:layout_marginTop="65dp"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="JBL"
        android:id="@+id/view_cart_item_brand"
        android:textSize="11dp"
        android:layout_marginLeft="180dp"
        android:layout_marginTop="65dp"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="P 1,290.00"
        android:id="@+id/view_cart_item_neww"
        android:textColor="#00c1ab"
        android:textSize="15dp"
        android:textStyle="bold"
        android:layout_marginLeft="140dp"
        android:layout_marginTop="83dp"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="P 2,580.00"
        android:textSize="11dp"
        android:id="@+id/view_cart_item_old"
        android:layout_marginLeft="140dp"
        android:layout_marginTop="106dp"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="- 50%"
        android:textSize="11dp"
        android:id="@+id/view_cart_item_discount"
        android:layout_marginLeft="210dp"
        android:textColor="#ba0101"
        android:layout_marginTop="106dp"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="P 1,290.00"
        android:textSize="11dp"
        android:layout_marginLeft="140dp"
        android:id="@+id/view_cart_item_new_depends_count"
        android:layout_marginTop="123dp"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="x"
        android:textSize="12dp"
        android:layout_marginLeft="240dp"
        android:textColor="#000"
        android:layout_marginTop="123dp"/>


    <ImageView
        android:layout_width="17dp"
        android:layout_height="17dp"
        android:src="@drawable/left_arrow"
        android:text="x"
        android:id="@+id/view_cart_item_increment"
        android:textSize="12dp"
        android:layout_marginLeft="250dp"
        android:layout_marginTop="123dp"/>


    <ImageView
        android:layout_width="17dp"
        android:layout_height="17dp"
        android:src="@drawable/right_arrow"
        android:text="x"
        android:id="@+id/view_cart_item_decrement"
        android:textSize="12dp"
        android:layout_marginLeft="304dp"
        android:layout_marginTop="123dp"/>

        <TextView
            android:layout_width="31dp"
            android:layout_height="16dp"
            android:textSize="11dp"
            android:textAlignment="center"
            android:text="100"
            android:id="@+id/view_cart_item_count"
            android:layout_marginLeft="270dp"
            android:layout_marginTop="123dp"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Color"
        android:textSize="11dp"
        android:textColor="#089bcc"
        android:layout_marginLeft="140dp"
        android:layout_marginTop="147dp"/>


    <ImageView
        android:layout_width="34dp"
        android:layout_height="17dp"
        android:textSize="12dp"
        android:id="@+id/view_cart_variant"
        android:background="@color/colorPrimaryDark"
        android:layout_marginLeft="175dp"
        android:layout_marginTop="145dp"/>


    </RelativeLayout>


</RelativeLayout>

</RelativeLayout>

我的购物车 View :

enter image description here

(如果你看到“<”和“>”标志，我试图在那里添加响应，但它与我的适配器一起在 RecyclerView 中运行，所以我不知道我是否可以将我的 onclick 事件放在哪里。 )

我在 recyclerview 中的 View (我设置评论我的//TODO :)(它正在运行，但没有加减功能。)

enter image description here

此外，我已经尝试过(holder.add.setOn ...)

enter image description here

还有这个:(MyViewHolder)

enter image description here

Answer 1

这是你需要了解的空指针异常。您应该将 itemView.findViewById(R.id.view_btn_add) 替换为 view.findViewById(R.id.view_btn_add)

因为适配器布局名称是view而不是itemview

看看你的代码

 public MyViewHolder(View view) {
      super(view);
}

并且您需要在 MyViewHolder() 或 onBindViewHolder()

中添加点击监听器

移动这段代码

add.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Toast.makeText(itemView.getContext(), "Add Click response properly.", Toast.LENGTH_SHORT).show();
                }
            });