代码实现简单的购物车

build.gradle

   apply plugin: 'com.android.application'
android {
    compileSdkVersion 25
    buildToolsVersion "26.0.2"

    defaultConfig {
        applicationId "gouwuche.bwei.com.gouwuche"
        minSdkVersion 15
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:25.+'
    compile 'com.android.support:recyclerview-v7:25.3.1'
    compile 'com.squareup.okhttp3:okhttp:3.9.0'
    compile 'com.google.code.gson:gson:2.8.2'
    compile 'com.jakewharton:butterknife:8.8.1'
    compile 'com.jakewharton:butterknife-compiler:8.8.1'
    compile 'com.nostra13.universalimageloader:universal-image-loader:1.9.5'

}

activity_main.xml

<!--?xml version="1.0" encoding="utf-8"?-->
<linearlayout xmlns:android="https://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent">
 
     
    <linearlayout android:layout_weight="0" android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:background="#FFFFFF" android:gravity="center_vertical" android:id="@+id/third_pay_linear">
 
        <checkbox android:id="@+id/third_allselect" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginleft="@dimen/margin_10dp" android:text="全选" android:drawablepadding="@dimen/padding_5dp">
 
        <linearlayout android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:orientation="vertical">
 
            <textview android:id="@+id/third_totalprice" android:layout_width="200dp" android:layout_height="wrap_content" android:paddingleft="@dimen/padding_10dp" android:paddingtop="@dimen/padding_10dp" android:text="总价：" android:textcolor="#000000" android:textsize="@dimen/common_font_size_16">
 
            <textview android:textcolor="#000000" android:id="@+id/third_totalnum" android:layout_width="wrap_content" android:layout_height="wrap_content" android:paddingleft="@dimen/padding_10dp" android:text="共0件商品" android:textsize="@dimen/common_font_size_14" android:paddingbottom="@dimen/padding_10dp">
 
        </textview></textview></linearlayout>
 
        <textview android:id="@+id/third_submit" android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="@drawable/login_btn" android:text="去结算" android:paddingleft="@dimen/margin_30dp" android:paddingright="@dimen/margin_30dp" android:paddingtop="@dimen/padding_10dp" android:paddingbottom="@dimen/padding_10dp" android:textcolor="#000000" android:layout_marginright="@dimen/margin_10dp">
 
    </textview></checkbox></linearlayout>
 
 
</android.support.v7.widget.recyclerview></linearlayout>

customview.xml

<!--?xml version="1.0" encoding="utf-8"?-->
<linearlayout xmlns:android="https://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent">
 
 
    <button android:layout_width="10dp" android:layout_height="wrap_content" android:id="@+id/revserse" android:text="-" android:background="#00FFFFFF">
    <edittext android:text="1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/content">
 
    </edittext></button><button android:background="#00FFFFFF" android:text="+" android:id="@+id/add" android:layout_width="10dp" android:layout_height="wrap_content">
 
</button></linearlayout>

shop_adapter.xml

<!--?xml version="1.0" encoding="utf-8"?-->
<relativelayout xmlns:android="https://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent">
    <linearlayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal">
        <checkbox android:id="@+id/checkbox" android:layout_margintop="20dp" android:layout_marginleft="20dp" android:layout_width="wrap_content" android:layout_height="wrap_content">
 
        <imageview android:id="@+id/shopface" android:layout_width="80dp" android:layout_height="80dp" android:layout_marginleft="20dp" android:src="@mipmap/ic_launcher">
 
        <textview android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margintop="30dp" android:layout_marginleft="20dp" android:id="@+id/danjia">
 
        <gouwuche.bwei.com.gouwuche.customview android:id="@+id/customviewid" android:layout_margintop="20dp" android:layout_marginleft="20dp" android:layout_width="100dp" android:layout_height="50dp">
 
 
    </gouwuche.bwei.com.gouwuche.customview></textview></imageview></checkbox></linearlayout>
    <button android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginleft="20dp" android:layout_margintop="20dp" android:layout_alignparentright="true" android:id="@+id/shop_btn_del" android:text="删除">
 
</button></relativelayout>

ShopActivity

package gouwuche.bwei.com.gouwuche;
import android.app.Activity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.widget.CheckBox;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.google.gson.Gson;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

import butterknife.BindView;
import butterknife.ButterKnife;
import butterknife.OnClick;

public class ShopActivity extends Activity {


    @BindView(R.id.third_recyclerview)
    RecyclerView thirdRecyclerview;
    @BindView(R.id.third_allselect)
    CheckBox thirdAllselect;
    @BindView(R.id.third_totalprice)
    TextView thirdTotalprice;
    @BindView(R.id.third_totalnum)
    TextView thirdTotalnum;
    @BindView(R.id.third_submit)
    TextView thirdSubmit;
    @BindView(R.id.third_pay_linear)
    LinearLayout thirdPayLinear;
    private List mAllOrderList = new ArrayList<>();
    private ShopAdapter adapter;
    private LinearLayoutManager manager;


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


        getData();

        // 1 为选中  2 选中
        thirdAllselect.setTag(1);

        manager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);

        adapter = new ShopAdapter(this);

        thirdRecyclerview.setLayoutManager(manager);
        thirdRecyclerview.setAdapter(adapter);

        adapter.add(mAllOrderList);


        adapter.setCheckBoxListener(new ShopAdapter.CheckBoxListener() {
            @Override
            public void check(int position, int count, boolean check, List list) {


                sum(list);
            }
        });

        adapter.setCustomViewListener(new ShopAdapter.CustomViewListener() {
            @Override
            public void click(int count, List list) {
                sum(list);
            }
        });

        adapter.setDelListener(new ShopAdapter.DelListener() {
            @Override
            public void del(int position, List list) {
                sum(list);
            }
        });


    }


    float price = 0;
    int count;

    /**
     * 计算总价
     *
     * @param mAllOrderList
     */
    private void sum(List mAllOrderList) {
        price = 0;
        count = 0;

        boolean allCheck = true;
        for (ShopBean.OrderDataBean.CartlistBean bean : mAllOrderList) {
            if (bean.isCheck()) {
                //得到总价
                price += bean.getPrice() * bean.getCount();
                //得到商品个数
                count += bean.getCount();
            } else {
                // 只要有一个商品未选中，全选按钮 应该设置成 未选中
                allCheck = false;
            }
        }

        thirdTotalprice.setText("总价: " + price);
        thirdTotalnum.setText("共" + count + "件商品");

        if (allCheck) {
            thirdAllselect.setTag(2);
            thirdAllselect.setChecked(true);
            //   thirdAllselect.setBackgroundResource(R.drawable.shopcart_selected);
        } else {
            thirdAllselect.setTag(1);
            thirdAllselect.setChecked(false);
            // thirdAllselect.setBackgroundResource(R.drawable.shopcart_unselected);
        }

    }


    public void getData() {
        try {
            //模拟网络请求
            InputStream inputStream = getAssets().open("shop.json");
            String data = convertStreamToString(inputStream);
            Gson gson = new Gson();
            ShopBean shopBean = gson.fromJson(data, ShopBean.class);


            for (int i = 0; i < shopBean.getOrderData().size(); i++) {
                int length = shopBean.getOrderData().get(i).getCartlist().size();
                for (int j = 0; j < length; j++) {
                    mAllOrderList.add(shopBean.getOrderData().get(i).getCartlist().get(j));
                }
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }


    public static String convertStreamToString(InputStream is) {
        /*
          * To convert the InputStream to String we use the BufferedReader.readLine()
          * method. We iterate until the BufferedReader return null which means
          * there's no more data to read. Each line will appended to a StringBuilder
          * and returned as String.
          */
        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        StringBuilder sb = new StringBuilder();

        String line = null;
        try {
            while ((line = reader.readLine()) != null) {
                sb.append(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        return sb.toString();
    }

    boolean select = false;

    @OnClick(R.id.third_allselect)
    public void onClick() {
        //全选按钮 点击事件

        int tag = (Integer) thirdAllselect.getTag();


        if (tag == 1) {
            thirdAllselect.setTag(2);
            select = true;

        } else {
            thirdAllselect.setTag(1);
            select = false;
        }
        for (ShopBean.OrderDataBean.CartlistBean bean : mAllOrderList) {
            bean.setCheck(select);
        }
        adapter.notifyDataSetChanged();

        sum(adapter.getList());


    }
}

ShopAdapter

package gouwuche.bwei.com.gouwuche;
import android.content.Context;
import android.content.DialogInterface;
import android.support.v7.app.AlertDialog;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.ImageView;
import android.widget.TextView;

import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;

import java.util.ArrayList;
import java.util.List;

import butterknife.BindView;
import butterknife.ButterKnife;

/**
 * Created by muhanxi on 17/11/15.
 */

public class ShopAdapter extends RecyclerView.Adapter {

    private Context context;
    private List list ;
    public ShopAdapter(Context context) {
        this.context = context;
    }


    /**
     * 更新数据
     * @param list
     */
    public void add(List list){
        if(this.list == null){
            this.list = new ArrayList<>();
            ImageLoader.getInstance().init(ImageLoaderConfiguration.createDefault(context));
        }
        this.list.addAll(list);
        notifyDataSetChanged();
    }

    @Override
    public IViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = View.inflate(context, R.layout.shop_adapter, null);
        return new IViewHolder(view);
    }

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



        //防止checkbox 滑动 错乱
        holder.checkbox.setChecked(list.get(position).isCheck());
        holder.customviewid.setEditText(list.get(position).getCount());
        holder.danjia.setText(list.get(position).getPrice()+"");

        ImageLoader.getInstance().displayImage(list.get(position).getDefaultPic(),holder.shopface);


        /**
         * checkbox 点击事件
         */
        holder.checkbox.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                list.get(position).setCheck(holder.checkbox.isChecked());
                notifyDataSetChanged();

                if(checkBoxListener != null){
                    checkBoxListener.check(position,holder.customviewid.getCurrentCount(),holder.checkbox.isChecked(),list);
                }
            }
        });


        /**
         * 加减监听
         */
        holder.customviewid.setListener(new CustomView.ClickListener() {
            @Override
            public void click(int count) {


                //更新数据源
                list.get(position).setCount(count);
                notifyDataSetChanged();

                if(listener != null){
                    listener.click(count,list);
                }


            }
        });

        /**
         * 删除点击事件
         */
        holder.del.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                new  AlertDialog.Builder(context)
                        .setTitle("是否确定删除" )
                        .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialogInterface, int i) {
                                list.remove(position);
                                notifyDataSetChanged();

                            }
                        })
                        .setNegativeButton("取消" ,  null )
                        .show();
               //list.remove(position);

                if(delListener != null){
                    delListener.del(position,list);
                }


            }
        });
    }

    @Override
    public int getItemCount() {
        return list == null ? 0 : list.size();
    }

    static class IViewHolder extends RecyclerView.ViewHolder {
        @BindView(R.id.checkbox)
        CheckBox checkbox;
        @BindView(R.id.shopface)
        ImageView shopface;
        @BindView(R.id.danjia)
        TextView danjia;
        @BindView(R.id.customviewid)
        CustomView customviewid;

        @BindView(R.id.shop_btn_del)
        Button del ;

        IViewHolder(View view) {
            super(view);
            ButterKnife.bind(this, view);
        }
    }



    public List getList(){
        return list;
    }

     CheckBoxListener checkBoxListener;

    /**
     * checkbox 点击事件
     * @param listener
     */
    public void setCheckBoxListener(CheckBoxListener listener){
        this.checkBoxListener = listener;
    }
     interface CheckBoxListener {
        public void check(int position, int count, boolean check, List list);
    }




     CustomViewListener listener;

    /**
     * 加减号 点击事件
     * @param listener
     */
    public void setCustomViewListener(CustomViewListener listener){
        this.listener = listener;
    }
     interface CustomViewListener {
        public void click(int count, List list);
    }



    DelListener delListener ;
    /**
     * 加减号 删除按钮事件
     * @param listener
     */
    public void setDelListener(DelListener listener) {
        this.delListener = listener ;
    }
    interface DelListener {
        public void del(int position, List list);
    }

}

CustomView

package gouwuche.bwei.com.gouwuche;
import android.content.Context;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;

/**
 * Created by muhanxi on 17/11/15.
 */

public class CustomView extends LinearLayout {

    private EditText editText;
    private Button revserse;
    private Button add;
    private int mCount = 1 ;

    public CustomView(Context context) {
        super(context);
    }

    public CustomView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);


        View view =   LayoutInflater.from(context).inflate(R.layout.customview,null,false);

        revserse = (Button) view.findViewById(R.id.revserse);
        add = (Button) view.findViewById(R.id.add);
        editText = (EditText) view.findViewById(R.id.content);


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

                //减号
                try {
                    String content =  editText.getText().toString().trim() ;

                    int count =  Integer.valueOf(content)-1;
                    if(count > 0){
                        editText.setText(count+"");
                        mCount = count-1;

                        if(listener != null){
                            listener.click(count);
                        }
                    }


                } catch (NumberFormatException e) {
                    e.printStackTrace();
                }


            }
        });


        add.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                //加号
                try {
                    String content =  editText.getText().toString().trim() ;
                    int count =  Integer.valueOf(content)+1;
                    mCount = count;

                    editText.setText(count+"");
                    if(listener != null){
                        listener.click(count);
                    }
                } catch (NumberFormatException e) {
                    e.printStackTrace();
                }
            }
        });


        addView(view);




    }

    public void setEditText(int count) {
        editText.setText(count+"");
    }

    public int getCurrentCount(){

        return mCount ;
    }

    public CustomView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }


    public ClickListener listener;

    public void setListener(ClickListener listener){
        this.listener = listener;
    }

    /**
     * 加减号 点击事件
     */
    public interface ClickListener {
        public void click(int count);
    }

}

ShopBean

assets里面要添加shop.json