Android————购物车(ShoppingCart)

实现功能
操作提示：选中所心仪的商品之后点击右下角支付图标显示总价格
1：增加商品个数，减少商品个数
2：统计所选中商品的价格
3：具有编辑功能（删除）
4：当商品被删除完之后跳转到空界面
效果图如下：


第一步：建立实体类Commodity
代码如下
/*此类用于对商品的
店铺名字
商品名字
价格
是否被选中
数量
进行定义
*/

public class Commodity {
private String StoreName;
private String CommodityName;
private double Price;
private int Number;
private boolean Is_Select;

public Commodity(){

}
public Commodity(String StoreName , String CommodityName , double Price , int Number , boolean Is_Select){
    this.StoreName = StoreName;
    this.CommodityName = CommodityName;
    this.Price = Price;
    this.Number = Number;
    this.Is_Select = Is_Select;
}

public String getStoreName() {
    return StoreName;
}

public void setStoreName(String storeName) {
    StoreName = storeName;
}

public String getCommodityName() {
    return CommodityName;
}

public void setCommodityName(String commodityName) {
    CommodityName = commodityName;
}

public double getPrice() {
    return Price;
}

public void setPrice(double price) {
    Price = price;
}

public int getNumber() {
    return Number;
}

public void setNumber(int number) {
    Number = number;
}

public boolean isIs_Select() {
    return Is_Select;
}

public void setIs_Select(boolean is_Select) {
    Is_Select = is_Select;
}

}

第二步：建立MyRecyclerView活动继承RecyclerView
代码如下:
public class MyRecyclerView extends RecyclerView.Adapter<MyRecyclerView.ViewHolder> {

private List<Commodity> ListCommodity;
public static double Money = 0; //用于返回总金额
private boolean DisplayDeleteControls = false; //用于表示是否显示删除按钮
public static int DelNum = 0;

public MyRecyclerView(List<Commodity> ListCommodity){
    this.ListCommodity = ListCommodity;
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerview_item,parent,false);
    return new ViewHolder(view);
}


@Override
public void onBindViewHolder(@NonNull final ViewHolder holder, final int position) {
    //final Commodity shop = ListCommodity.get(position);
    holder.StoreName.setText(ListCommodity.get(position).getStoreName());
    holder.CommodityName.setText(ListCommodity.get(position).getCommodityName());
    holder.Price.setText(ListCommodity.get(position).getPrice() + "");
    holder.Number.setText(ListCommodity.get(position).getNumber() + "");
    holder.CommodityCheckBox.setChecked(ListCommodity.get(position).isIs_Select());
    //显示删除按钮
    if (DisplayDeleteControls == true)
    {
        holder.Del.setVisibility(View.VISIBLE);

    }
    else
    {
        holder.Del.setVisibility(View.GONE);

    }


    //增加商品数量
    holder.CommodityNumAdd.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

                ListCommodity.get(position).setNumber(ListCommodity.get(position).getNumber() + 1);
                notifyDataSetChanged();

        }
    });
    //减少商品数量
    holder.CommodityNumSub.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (ListCommodity.get(position).getNumber() > 1){
                ListCommodity.get(position).setNumber(ListCommodity.get(position).getNumber() - 1);
                notifyDataSetChanged();
            }
        }
    });
    //判断是否选中
    holder.CommodityCheckBox.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            CheckBox Select = (CheckBox) v;
            if (Select.isChecked())
            {
                ListCommodity.get(position).setIs_Select(true);
            }
            else
            {
                ListCommodity.get(position).setIs_Select(false);
            }
            notifyDataSetChanged();
        }
    });
    //删除对应商品
    holder.Del.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            ListCommodity.remove(position);
            notifyDataSetChanged();

            if (ListCommodity.size() == 0)
            {
                DelNum = 1;
            }
        }
    });
}

//把隐藏的删除按钮显示出来
public void ShowDelButton(boolean DisplayDeleteControls)
{
    if (DisplayDeleteControls == true)
    {
        this.DisplayDeleteControls = true;
    }
    else
    {
        this.DisplayDeleteControls = false;
    }
    this.notifyDataSetChanged();
}

//是否全选，因为全选按钮不在适配器布局中，所以得用主函数调用
public void SelectAll (boolean IsSelect){
for (int j = 0; j < ListCommodity.size(); j++) {
if (IsSelect == true)
{
ListCommodity.get(j).setIs_Select(true);
}
else
{
ListCommodity.get(j).setIs_Select(false);
}
}
this.notifyDataSetChanged();
}
//获取选中商品的数量和金额，返回总金额
public double TotalMoney()
{
double Money = 0;
for (int i = 0; i < ListCommodity.size(); i++) {
if (ListCommodity.get(i).isIs_Select() == true)
{
Money += (ListCommodity.get(i).getNumber()) * (ListCommodity.get(i).getPrice());
}
}
return Money;
}
@Override
public int getItemCount() {
return ListCommodity.size();
}

static class ViewHolder extends RecyclerView.ViewHolder{

    TextView StoreName,CommodityName,Price,Number;
    ImageButton CommodityNumSub,CommodityNumAdd;
    CheckBox CommodityCheckBox;
    ImageView StoreImage,CommodityImage,MoneyImage;
    Button Del;

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

        StoreName = (TextView) itemView.findViewById(R.id.StoreName);
        CommodityName = (TextView) itemView.findViewById(R.id.CommodityName);
        Price = (TextView) itemView.findViewById(R.id.CommodityMoney);
        Number = (TextView) itemView.findViewById(R.id.CommodityNumber);

        StoreImage = (ImageView) itemView.findViewById(R.id.StoreImage);
        CommodityImage = (ImageView) itemView.findViewById(R.id.CommodityImage);
        MoneyImage = (ImageView) itemView.findViewById(R.id.CommodityMoneyImage);
        CommodityNumSub = (ImageButton) itemView.findViewById(R.id.CommodityNumberSub);
        CommodityNumAdd = (ImageButton) itemView.findViewById(R.id.CommodityNumberAdd);

        CommodityCheckBox = (CheckBox) itemView.findViewById(R.id.CommodityCheckBox);

        Del = (Button) itemView.findViewById(R.id.Del);
    }
}

}

MyRecyclerView布局文件代码
效果图如下:

代码如下:
<?xml version="1.0" encoding="utf-8"?>

    <ImageView
            android:id="@+id/StoreImage"
            android:layout_width="40dp"
            android:layout_height="40dp"
            android:layout_marginLeft="5dp"
            android:src="@drawable/store"
            android:scaleType="centerInside"/>
    <TextView
            android:id="@+id/StoreName"
            android:layout_width="100dp"
            android:layout_height="40dp"
            android:layout_marginLeft="15dp"
            android:layout_marginTop="0dp"
            android:text="店铺"
            android:textColor="#000"
            android:textSize="30sp"/>
</LinearLayout>
<View
  android:layout_width="match_parent"
  android:layout_height="1dp"
  android:layout_marginTop="60dp"
  android:background="#000"/>
<CheckBox
  android:id="@+id/CommodityCheckBox"
  android:layout_width="30dp"
  android:layout_height="30dp"
  android:layout_marginTop="130dp"
  android:layout_marginLeft="10dp"/>
<ImageView
  android:id="@+id/CommodityImage"
  android:layout_width="150dp"
  android:layout_height="150dp"
  android:src="@drawable/bg"
  android:scaleType="centerInside"
  android:layout_marginTop="70dp"
  android:layout_marginLeft="50dp"/>
<TextView
  android:id="@+id/CommodityName"
  android:layout_width="100dp"
  android:layout_height="30dp"
  android:text="商品名字"
  android:layout_marginTop="80dp"
  android:layout_marginLeft="210dp"
  android:textColor="#000"
  android:textSize="20sp"/>
<ImageView
  android:id="@+id/CommodityMoneyImage"
  android:layout_width="30dp"
  android:layout_height="20dp"
  android:src="@drawable/money"
  android:scaleType="centerInside"
  android:layout_marginLeft="200dp"
  android:layout_marginTop="170dp"/>
<TextView
  android:id="@+id/CommodityMoney"
  android:layout_height="50dp"
  android:layout_width="70dp"
  android:text="0.0"
  android:layout_marginLeft="235dp"
  android:layout_marginTop="167dp"
  android:textSize="20sp"
  android:textColor="#ff0000"
  android:singleLine="true"/>
<ImageButton
  android:id="@+id/CommodityNumberSub"
  android:layout_width="30dp"
  android:layout_height="30dp"
  android:src="@drawable/shoppingcartsub"
  android:scaleType="centerInside"
  android:background="#ffffff"
  android:layout_marginTop="170dp"
  android:layout_marginLeft="283dp"/>
<TextView
  android:id="@+id/CommodityNumber"
  android:layout_width="20dp"
  android:layout_height="20dp"
  android:layout_marginLeft="315dp"
  android:layout_marginTop="175dp"
  android:textSize="15sp"
  android:textColor="#ff0000"
  android:text="1"/>
<ImageButton
  android:id="@+id/CommodityNumberAdd"
  android:layout_width="30dp"
  android:layout_height="30dp"
  android:src="@drawable/shoppingcartadd"
  android:scaleType="centerInside"
  android:background="#ffffff"
  android:layout_marginTop="170dp"
  android:layout_marginLeft="330dp"/>
<Button
  android:id="@+id/Del"
  android:layout_width="40dp"
  android:layout_height="100dp"
  android:text="删除"
  android:background="#ff0000"
  android:textSize="20sp"
  android:layout_alignParentRight="true"
  android:layout_marginTop="80dp"
  android:visibility="gone"/>

第三步：建立MainActicity代码如下: public class MainActivity extends AppCompatActivity{

private RecyclerView Recycler;
private TextView AllSelectEventWords, TotalMoneyEventWords, Title, TotalMoney;
private ImageView MoneyImage;
private ImageButton PayImageButton;
private CheckBox AllSelect;
private Button Edit;


private MyRecyclerView adapter;
private List<Commodity> ListCommodity = new ArrayList<>();
//自定义信息
//店铺名字，商品名字，价格，数量，是否被选择
private String[][] CommodityData = {
        {"儿童店", "奶嘴", "39.9", "2", "false"},
        {"青年店", "篮球鞋", "999", "1", "false"},
        {"中年店", "假发", "1999", "1", "false"},
        {"老年店", "假牙", "59.9", "1", "false"}
};

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

    Recycler = (RecyclerView) findViewById(R.id.recyclerview);

    MoneyImage = (ImageView) findViewById(R.id.MoneyImage);
    PayImageButton = (ImageButton) findViewById(R.id.PayImage);

    AllSelect = (CheckBox) findViewById(R.id.AllSelectImage);

    Title = (TextView) findViewById(R.id.Title);
    AllSelectEventWords = (TextView) findViewById(R.id.AllSelectText);
    TotalMoneyEventWords = (TextView) findViewById(R.id.TotalMoneyText);
    TotalMoney = (TextView) findViewById(R.id.TotalMoney);
    Edit = (Button) findViewById(R.id.Edit);
    //初始化数据
    InitData();

    LinearLayoutManager manager = new LinearLayoutManager(MainActivity.this);
    Recycler.setLayoutManager(manager);

    adapter = new MyRecyclerView(ListCommodity);
    Recycler.setAdapter(adapter);
    double Money = MyRecyclerView.Money;
    TotalMoney.setText(Money+"");

    //全选操作
    AllSelect.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (adapter != null) {
                CheckBox Select = (CheckBox) v;
                if (Select.isChecked() == true)
                {
                    adapter.SelectAll(true);
                }
                else
                {
                    adapter.SelectAll(false);
                }

            }
        }
    });
    //获取所选中商品的总金额
    PayImageButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            double Money = adapter.TotalMoney();
            TotalMoney.setText(Money+"");

            if (Money > 10)
            {
                Toast.makeText(MainActivity.this,"支付成功!",Toast.LENGTH_SHORT).show();
            }
        }
    });
    //点击编辑按钮
    Edit.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            if (adapter != null)
            {
                if (Edit.getText().equals("编辑"))
                {
                    Edit.setText("完成");
                    adapter.ShowDelButton(true);
                    if (adapter.DelNum == 1)
                    {
                        Intent intent = new Intent(MainActivity.this,EmptyInterface.class);
                        startActivity(intent);
                    }

                }
                else
                {
                    Edit.setText("编辑");
                    adapter.ShowDelButton(false);
                }
            }
        }

    });
}
    public void InitData () {

        Commodity commodity = null;
        for (int i = 0; i < 4; i++) {
            for (int j = 0; j < 1; j++) {

                String StoreName = CommodityData[i][j];
                String CommodityName = CommodityData[i][j + 1];
                double Money = 0;
                int Num = 0;
                boolean is_Select = false;
                try {
                    Money = Double.valueOf(CommodityData[i][j + 2]);
                    Num = Integer.parseInt(CommodityData[i][j + 3]);
                    is_Select = Boolean.parseBoolean(CommodityData[i][j + 4]);
                } catch (NumberFormatException e) {
                    e.printStackTrace();
                }
                commodity = new Commodity(StoreName, CommodityName, Money, Num, is_Select);
                //adapter.notifyItemChanged(ListCommodity.size()-1);
                Recycler.scrollToPosition(ListCommodity.size() - 1);
            }
            ListCommodity.add(commodity);

        }
    }
}

<font  size="5" color = #ff0000>效果图如下:</font>

MainActivity布局文件代码
<?xml version="1.0" encoding="utf-8"?>




<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recyclerview"
android:layout_height=“wrap_content”
android:layout_width=“match_parent”
android:layout_marginTop=“70dp”/>







第四步：建立一个空活动，不执行任何东西，用于商品被删除完之后跳转到此界面
代码太过于简单，在此不展示，直接上效果图

下面展示一个细节效果图
点击编辑按钮，然后出现删除按钮，删除按钮是被隐藏的