第二个页面

package com.bawei.yuezkao1.view.fragment;


import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.TextView;

import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import com.bawei.yuezkao1.R;
import com.bawei.yuezkao1.model.bean.HomeshopsBean;
import com.bawei.yuezkao1.model.bean.MessageBean;
import com.bawei.yuezkao1.view.activity.Main3Activity;
import com.bawei.yuezkao1.view.adapter.GWC_Adapter;

import org.greenrobot.eventbus.EventBus;
import org.greenrobot.eventbus.Subscribe;
import org.greenrobot.eventbus.ThreadMode;

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

import butterknife.BindView;
import butterknife.ButterKnife;
import butterknife.OnClick;
import butterknife.Unbinder;
import io.realm.Realm;

/**
 * A simple {@link Fragment} subclass.
 */
public class GWCFragment extends Fragment {


    @BindView(R.id.recyclerView_gwc)
    RecyclerView recyclerViewGwc;
    @BindView(R.id.checkbox_all)
    CheckBox checkboxAll;
    @BindView(R.id.textView_price)
    TextView textViewPrice;
    @BindView(R.id.textView_count)
    TextView textViewCount;

    private Unbinder unbinder;
    private Realm realm;
    private List<HomeshopsBean> homeshopsBeanList;
    private List<HomeshopsBean> homeshopsBeanListSelected=new ArrayList<>();
    private GWC_Adapter gwc_adapter;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_gwc, container, false);
        unbinder= ButterKnife.bind(this,view);
        realm=Realm.getDefaultInstance();
        return view;
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        recyclerViewGwc.setLayoutManager(new LinearLayoutManager(getActivity()));
        //查询数据库购物车数据并展示
        homeshopsBeanList=realm.where(HomeshopsBean.class).findAll();
        gwc_adapter=new GWC_Adapter(getActivity(),homeshopsBeanList);
        recyclerViewGwc.setAdapter(gwc_adapter);
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        unbinder.unbind();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        if(!realm.isClosed()){
            realm.close();
        }
    }
    //全选
    @OnClick(R.id.checkbox_all)
    public void onViewClicked(){
        realm.beginTransaction();//开启事务
        boolean checked=checkboxAll.isChecked();
        for (int i = 0; i <homeshopsBeanList.size() ; i++) {
            homeshopsBeanList.get(i).setSelected(checked);
        }
        //计算总价和总量
        calcTotal();
        realm.commitTransaction();//提交事务
        
    }
    /**
     * 存储总价的变量
     */
    private int totalPrice;
    /**
     * 存储选中商品总数量
     */
    private int totalCount;
    /**
     * 标识商品是否是全选的变量
     */
    private boolean isSelectAll;

    private void calcTotal() {
        totalPrice=0;//重置商品总价
        totalCount=0;//重置商品总量
        isSelectAll=true;//重置全选按钮的状态
        for (int i = 0; i <homeshopsBeanList.size() ; i++) {
            if(homeshopsBeanList.get(i).isSelected()){
                // 累计价格
                totalPrice+=homeshopsBeanList.get(i).getNowprice();
                // 累计数量
                totalCount+=1;
            }else {
                isSelectAll=false;//如果有一件没选中全选就是false

            }
        }
        // 刷新适配器
        gwc_adapter.notifyDataSetChanged();
        // 设置总价
        textViewPrice.setText("总价:￥"+totalPrice);
        // 设置总数量
        textViewCount.setText("共计"+totalCount+"件商品");
        // 修改页面
        checkboxAll.setChecked(isSelectAll);
    }
    @Subscribe(threadMode = ThreadMode.MAIN)
    public void getEvent(MessageBean messageBean){
        //收到计算总价和总量的事件
        if("计算总量和总价".equals(messageBean.getMessage())){
            calcTotal();
        }
    }
    @Override
    public void onStart() {
        super.onStart();
        EventBus.getDefault().register(this);
    }

    @Override
    public void onStop() {
        super.onStop();
        EventBus.getDefault().unregister(this);
    }
    /*立即结算购买*/
    @OnClick(R.id.button_jiesuan)
    public void jiesuan(){
        homeshopsBeanListSelected.clear();//清空一下上次的数据
        for (int i = 0; i <homeshopsBeanList.size() ; i++) {
            if(homeshopsBeanList.get(i).isSelected()){//用户选中的商品
                homeshopsBeanListSelected.add(homeshopsBeanList.get(i));
            }
        }
        EventBus.getDefault().postSticky(homeshopsBeanListSelected);
        //跳转到确认订单页面
        Intent intent=new Intent(getActivity(),Main3Activity.class);
        startActivity(intent);

    }

}