Recyclerview 独立按钮和计数器

Question

我有问题。 2 个按钮（+ 和 -）具有相同的计数器。例如，当我增加可乐（假设我们想要 2 杯可乐）时，我按下按钮 2 次，一切正常，但只要我想要炸薯条（1 炸薯条和 2 杯可乐），炸薯条的柜台就会增加到3 而它应该是 1 因为我第一次点击它。下图显示了问题。

以下 xml 和 java 类文件重建您看到的图像。或许你能帮帮我，我会很感激的。

OrderActivity.java

package com.nfc.netvision;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.os.Bundle;

import java.util.ArrayList;

public class OrderActivity extends AppCompatActivity {

    RecyclerView recyclerView;

    ArrayList<ModelOrder> orderArrayList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_order);

        recyclerView = findViewById(R.id.recyclerview_order_scroll);

        orderArrayList = new ArrayList<>();
        orderArrayList.add(new ModelOrder(R.drawable.coke, "Coka Cola", "Kaltes Getränml", "6"));
        orderArrayList.add(new ModelOrder(R.drawable.fastfood, "Coka Cola", "Kaltes Getränml", "10"));
        orderArrayList.add(new ModelOrder(R.drawable.water, "Coka Cola", "Kaltes Getränml", "20"));
        orderArrayList.add(new ModelOrder(R.drawable.burger, "Coka Cola", "Kaltes Getränml", "30"));

        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        RecyclerView.LayoutManager recLiLayoutManager = layoutManager;

        recyclerView.setLayoutManager(recLiLayoutManager);

        OrderAdapter adapter = new OrderAdapter(this, orderArrayList);

        recyclerView.setAdapter(adapter);
    }
}

OrderAdapter.java

package com.nfc.netvision;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import java.util.ArrayList;

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

    int value = 0; //Global
    private Context mContext;
    private ArrayList<ModelOrder> nList;
    OrderAdapter(Context context, ArrayList<ModelOrder> list) {
        mContext = context;
        nList = list;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

        LayoutInflater layoutInflater = LayoutInflater.from(mContext);
        View view = layoutInflater.inflate(R.layout.recyclerview_order_items, parent, false);

        ViewHolder viewHolder = new ViewHolder(view);
        return viewHolder;
    }

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

        ModelOrder orderItem = nList.get(position);
        ImageView image = holder.item_image;
        TextView name, place, price;
        name = holder.item_name;
        place = holder.item_place;
        price = holder.item_price;

        image.setImageResource(orderItem.getImage());

        name.setText(orderItem.getName());
        place.setText(orderItem.getPlace());
        price.setText(orderItem.getPrice());


        holder.order_item_minus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {


                value = value - 1;
                holder.order_item_count.setText("" + value);

            }
        });

        holder.order_item_plus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {


                value = value + 1;
                holder.order_item_count.setText("" + value);

            }
        });





    }

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

    public class ViewHolder extends RecyclerView.ViewHolder {

        ImageView item_image;
        TextView item_name, item_place, item_price,order_item_minus,order_item_count, order_item_plus;

        public ViewHolder(@NonNull View itemView) {

            super(itemView);
            item_image = itemView.findViewById(R.id.order_item_image);
            item_name = itemView.findViewById(R.id.order_item_name);
            item_place = itemView.findViewById(R.id.order_item_place);
            item_price = itemView.findViewById(R.id.order_item_price);
            order_item_minus = itemView.findViewById(R.id.order_item_minus);
            order_item_plus = itemView.findViewById(R.id.order_item_plus);
            order_item_count = itemView.findViewById(R.id.order_item_count);
        }
    }
}

recyclerViewer.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="10dp">

    <LinearLayout
        android:weightSum="10"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <ImageView
            android:id="@+id/order_item_image"
            android:layout_width="0dp"
            android:layout_weight="4"
            android:layout_height="128dp"
            android:scaleType="centerCrop"
            android:src="@drawable/coke"/>
        <LinearLayout
            android:layout_width="0dp"
            android:layout_weight="4"
            android:layout_height="wrap_content"
            android:orientation="vertical">

            <TextView
                android:id="@+id/order_item_name"
                android:textSize="18sp"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textStyle="bold"
                android:text="Name"/>

            <TextView
                android:id="@+id/order_item_place"
                android:text="Description"
                android:textSize="14sp"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"/>


        </LinearLayout>
        <TextView
            android:id="@+id/order_item_price"
            android:text="€ Preis"
            android:layout_width="0dp"
            android:layout_weight="2"
            android:layout_gravity="center"
            android:gravity="center"
            android:textColor="#fff"
            android:background="@drawable/capsule_order"
            android:layout_height="30dp"/>
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom">
            <TextView
                android:id="@+id/order_item_minus"
                android:layout_width="28dp"
                android:layout_height="28dp"
                android:textSize="25dp"
                android:layout_gravity="center"
                android:gravity="center"
                android:background="@drawable/capsule_order"
                android:textColor="#fff"
                android:textStyle="bold"
                android:text="-"/>
            <TextView
                android:id="@+id/order_item_count"
                android:layout_width="28dp"
                android:layout_height="28dp"
                android:textSize="25dp"
                android:layout_gravity="center"
                android:gravity="center"
                android:textColor="#000"
                android:textStyle="bold"
                android:text="00"/>
            <TextView
                android:id="@+id/order_item_plus"
                android:layout_width="28dp"
                android:layout_height="28dp"
                android:textSize="25dp"
                android:layout_gravity="center"
                android:gravity="center"
                android:background="@drawable/capsule_order"
                android:textColor="#fff"
                android:textStyle="bold"
                android:text="+"/>
        </LinearLayout>

    </LinearLayout>
</androidx.cardview.widget.CardView>

activity_order.xml

<androidx.coordinatorlayout.widget.CoordinatorLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">

            <androidx.core.widget.NestedScrollView
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:clipToPadding="true"
                app:layout_behavior="@string/appbar_scrolling_view_behavior">

                <androidx.recyclerview.widget.RecyclerView
                    android:id="@+id/recyclerview_order_scroll"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    >

                </androidx.recyclerview.widget.RecyclerView>
            </androidx.core.widget.NestedScrollView>

Answer 1

因为你总是访问你在 Adapter 中初始化的 value 变量

解决方案是 将 value 添加到您的 ModelOrder 并在模型中启动它

然后访问它

所以..每一行都会不同

OrderActivity.java // 用 counter = 0

初始化每个模型

orderArrayList.add(new ModelOrder(R.drawable.coke, "Coka Cola", "Kaltes Getränml", "6",0));
orderArrayList.add(new ModelOrder(R.drawable.fastfood, "Coka Cola", "Kaltes Getränml", "10",0));
orderArrayList.add(new ModelOrder(R.drawable.water, "Coka Cola", "Kaltes Getränml", "20",0));
orderArrayList.add(new ModelOrder(R.drawable.burger, "Coka Cola", "Kaltes Getränml", "30",0));

OrderAdapter.java

删除这一行

int 值 = 0; //全局

holder.order_item_minus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                orderItem.setCounter(orderItem.getCounter()-1);
                holder.order_item_count.setText("" + orderItem.getCounter());
            }
        });

 holder.order_item_plus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                orderItem.setCounter(orderItem.getCounter()+1);
                holder.order_item_count.setText("" + orderItem.getCounter());
            }
        });

Answer 2

您必须在 ModelOrder 中添加具有 INT 数据类型的 'quantity' 属性 因此，根据加/减按钮单击增加/减少对象中 'quantity' 的值，并在计数器文本视图中设置 'quantity' 值