查询购物车---二级列表实现

==================实现思路==================

/**

 *1.点击全选:选中/未选中...调用适配器中的方法...myAdapter.setIsCheckAll(true);来设置所有的一级和二级是否选中,计算

 *

 * 2.一级列表的点击事件:

 *      2.1改变当前一级选中的状态...dataBean.setChoosed(! dataBean.isChoosed());

 *      2.2根据当前一级的状态,改变该组里面二级列表的状态....changeChilState(groupPosition,dataBean.isChoosed());

 *      2.3通过判断所有的一级组是否选中,来决定是否全选选中:...changeAllState(isAllGroupChecked());

 *      2.4发送价格个数量:...sendPriceAndCount();

 *      2.5刷新适配器

 * 3.二级列表点击事件:

 *      3.1点击改变当前子条目状态:...listBean.setChildChoosed(! listBean.isChildChoosed());//相反

 *      3.2发送价钱和数量给界面显示....sendPriceAndCount();

 *      3.3如果当前子条目是选中状态

 *          3.3.1选中

 *              判断一下当前组中所有的子条目是否全部选中:...isAllChildSelected(groupPosition)

 *              如果全部选中改变一下当前组的状态:...changGroupState(groupPosition,true);...确定是否改变全选changeAllState(isAllGroupChecked());

 *          3.3.2未选中

 *              changGroupState(groupPosition,false);改变当前组false...是否全选changeAllState(isAllGroupChecked());

 */

------------------------适配器-------------自定义expandablelistview-----------------

public class MyAdapter extends BaseExpandableListAdapter{

    private Handler handler;

    private Context context;

    private List<CartBean.DataBean> listGroup;

    private List<List<CartBean.DataBean.ListBean>> listChilds;

    public MyAdapter(Context context, List<CartBean.DataBean> listGroup, List<List<CartBean.DataBean.ListBean>> listChilds, Handler handler) {

        this.context = context;

        this.listGroup = listGroup;

        this.listChilds = listChilds;

        this.handler = handler;

    }

    @Override

    public int getGroupCount() {

        return listGroup.size();

    }

    @Override

    public int getChildrenCount(int groupPosition) {

        return listChilds.get(groupPosition).size();

    }

    @Override

    public Object getGroup(int groupPosition) {

        return listGroup.get(groupPosition);

    }

    @Override

    public Object getChild(int groupPosition, int childPosition) {

        return listChilds.get(groupPosition).get(childPosition);

    }

    @Override

    public long getGroupId(int groupPosition) {

        return groupPosition;

    }

    @Override

    public long getChildId(int groupPosition, int childPosition) {

        return childPosition;

    }

    @Override

    public boolean hasStableIds() {

        return true;

    }

    @Override

    public View getGroupView(final int groupPosition, boolean b, View view, ViewGroup viewGroup) {

        GroupHolder holder;

        if (view == null){

            view = View.inflate(context, R.layout.group_item_layout,null);

            holder = new GroupHolder();

            holder.check_group = view.findViewById(R.id.check_group);

            holder.text_group = view.findViewById(R.id.text_group);

            view.setTag(holder);

        }else {

            holder = (GroupHolder) view.getTag();

        }

        final CartBean.DataBean dataBean = listGroup.get(groupPosition);

        //赋值

        holder.check_group.setChecked(dataBean.isGroupChecked());

        holder.text_group.setText(dataBean.getSellerName());

        //设置点击事件

        holder.check_group.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View view) {

                //2.1改变当前一级选中的状态

                dataBean.setGroupChecked(! dataBean.isGroupChecked());

                //2.2根据当前一级的状态,改变该组里面二级列表的状态

                changeChildState(groupPosition,dataBean.isGroupChecked());

                //2.3通过判断所有的一级组是否选中,来决定是否全选选中

                changeAllState(isAllGroupChecked());

                //2.4发送价格个数量:

                sendPriceAndCount();

                //刷新适配器

                notifyDataSetChanged();

            }

        });

        return view;

    }

    /**

     * 根据所有一级列表是否选中,确定外面的全选是否选中

     * @param allGroupChecked

     */

    private void changeAllState(boolean allGroupChecked) {

        Message msg = Message.obtain();

        msg.what =1;

        msg.obj = allGroupChecked;

        handler.sendMessage(msg);

    }

    /**

     * 所有的一级列表是否选中

     * @return

     */

    private boolean isAllGroupChecked() {

        for (int i=0;i<listGroup.size();i++){

            if (! listGroup.get(i).isGroupChecked()){

                return false;

            }

        }

        return true;

    }

    /**

     * 根据当前一级列表的状态,,,改变当前组中所有二级列表的状态

     * @param groupPosition

     * @param groupChecked

     */

    private void changeChildState(int groupPosition, boolean groupChecked) {

        List<CartBean.DataBean.ListBean> listBeans = listChilds.get(groupPosition);

        for (int i=0;i<listBeans.size();i++){

            listBeans.get(i).setSelected(groupChecked? 1:0);

        }

    }

    @Override

    public View getChildView(final int groupPosition, int childPosition, boolean b, View view, ViewGroup viewGroup) {

        ChildHolder holder;

        if (view == null){

            view = View.inflate(context, R.layout.child_item_layout,null);

            holder = new ChildHolder();

            holder.text_add = view.findViewById(R.id.text_add);

            holder.text_num = view.findViewById(R.id.text_num);

            holder.text_jian = view.findViewById(R.id.text_jian);

            holder.text_title = view.findViewById(R.id.text_title);

            holder.text_price = view.findViewById(R.id.text_price);

            holder.image_good = view.findViewById(R.id.image_good);

            holder.check_child = view.findViewById(R.id.check_child);

            view.setTag(holder);

        }else {

            holder = (ChildHolder) view.getTag();

        }

       //赋值

        final CartBean.DataBean.ListBean listBean = listChilds.get(groupPosition).get(childPosition);

        holder.text_num.setText(listBean.getNum()+"");//......注意

        holder.text_price.setText("¥"+listBean.getPrice());<
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        holder.text_title.setText(listBean.getTitle());

        //listBean.getSelected().....0false,,,1true

        //设置checkBox选中状态

        holder.check_child.setChecked(listBean.getSelected()==0? false:true);

        /*implementation 'com.github.bumptech.glide:glide:4.4.0'

        annotationProcessor 'com.github.bumptech.glide:compiler:4.4.0'*/

        Glide.with(context).load(listBean.getImages().split("\\|")[0]).into(holder.image_good);

        //设置点击事件

        holder.check_child.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View view) {

                //3.1点击改变当前子条目状态:....实际是改变当前的数据,,,刷新适配器

                listBean.setSelected(listBean.getSelected() ==0? 1:0);

                //3.2发送价钱和数量给界面显示

                sendPriceAndCount();

                //3.3判断当前子条目是否选中

                if (listBean.getSelected() == 1){

                    //判断一下当前组中所有的子条目是否全部选中

                    if (isAllChildSelected(groupPosition)){

                        //如果全部选中改变一下当前组的状态

                        changeGroupState(groupPosition,true);

                        //.确定是否改变全选

                        changeAllState(isAllGroupChecked());

                    }

                }else {

                    //如果没有选中改变一下当前组的状态

                    changeGroupState(groupPosition,false);

                    //.确定是否改变全选

                    changeAllState(isAllGroupChecked());

                }

                //刷新适配器

                notifyDataSetChanged();

            }

        });

        //加号:

        holder.text_add.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View view) {

                //改变当前位置 中商品的数量

                listBean.setNum(listBean.getNum()+1);

                //判断一下是否选中...计算价格数量

                if (listBean.getSelected() == 1){

                    sendPriceAndCount();

                }

                //

                notifyDataSetChanged();

            }

        });

        //减号

        holder.text_jian.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View view) {

                int num = listBean.getNum();

                if (num == 1){

                    return;

                }

                listBean.setNum(num -1);

                //判断是否选中

                if (listBean.getSelected() == 1){

                    sendPriceAndCount();

                }

                notifyDataSetChanged();

            }

        });

        return view;

    }

    /**

     * 改变当前组的状态

     * @param groupPosition

     * @param b

     */

    private void changeGroupState(int groupPosition, boolean b) {

        listGroup.get(groupPosition).setGroupChecked(b);

    }

    /**

     * 判断当前组中所有的二级是否选中

     * @param groupPosition

     * @return

     */

    private boolean isAllChildSelected(int groupPosition) {

        List<CartBean.DataBean.ListBean> listBeans = listChilds.get(groupPosition);

        for (int i=0;i<listBeans.size();i++){

            if (listBeans.get(i).getSelected() == 0){

                return false;

            }

        }

        return true;

    }

    @Override

    public boolean isChildSelectable(int groupPosition, int childPosition) {

        return true;//子条目是否可以点击

    }

    /**

     * 设置是否全选

     * @param checked

     */

    public void setIfCheckAll(boolean checked) {

        for (int i = 0;i<listGroup.size();i++){

            CartBean.DataBean dataBean = listGroup.get(i);

            //设置组上面的checkBox是否选中

            dataBean.setGroupChecked(checked);

            List<CartBean.DataBean.ListBean> listBeans = dataBean.getList();

            for (int j = 0; j< listBeans.size(); j++){

                //改变是否选中的状态...数据应该变的是

                listBeans.get(j).setSelected(checked? 1:0);

            }

        }

        //计算价钱和数量并且发送到mainActivity显示

        sendPriceAndCount();

        //刷新适配器

        notifyDataSetChanged();

    }

    /**

     * 计算总价和数量,,,发送显示

     */

    private void sendPriceAndCount() {

        double price = 0;

        int count = 0;

        for (int i=0;i<listGroup.size();i++){

            List<CartBean.DataBean.ListBean> listBeans = listGroup.get(i).getList();

            for (int j = 0;j<listBeans.size();j++){

                CartBean.DataBean.ListBean listBean = listBeans.get(j);

                if (listBean.getSelected()==1){

                    price += listBean.getPrice()* listBean.getNum();

                    count += listBean.getNum();

                }

            }

        }

        CountPriceBean countPriceBean = new CountPriceBean(price, count);

        //显示到activity页面

        Message msg = Message.obtain();

        msg.what = 0;

        msg.obj = countPriceBean;

        handler.sendMessage(msg);

    }

    private class GroupHolder{

        CheckBox check_group;

        TextView text_group;

    }

    private class ChildHolder{

        CheckBox check_child;

        ImageView image_good;

        TextView text_title;

        TextView text_price;

        TextView text_jian;

        TextView text_num;

        TextView text_add;

    }

}

---------------------------activity----------------------------------

public class MainActivity extends AppCompatActivity implements IMainActivity, View.OnClickListener {

    private CartExpanableListview expanableListview;

    private String cartUrl = "https://www.zhaoapi.cn/product/getCarts?uid=3004";

    private CartPresenter cartPresenter;

    private Gson gson;

    private MyAdapter myAdapter;

    private CheckBox check_all;

    private TextView text_total;

    private TextView text_buy;

    private Handler handler = new Handler(){

        @Override

        public void handleMessage(Message msg) {

            if (msg.what == 0){

                CountPriceBean countPriceBean = (CountPriceBean) msg.obj;

                //设置

                text_total.setText("合计:¥"+countPriceBean.getPrice());

                text_buy.setText("去结算("+countPriceBean.getCount()+")");

            }else  if (msg.what == 1){//改变全选

                boolean flag = (boolean) msg.obj;

                check_all.setChecked(flag);

            }

        }

    };

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        check_all = findViewById(R.id.check_all);

        text_total = findViewById(R.id.text_total);

        text_buy = findViewById(R.id.text_buy);

        expanableListview = findViewById(R.id.expanable_listview);

        //去掉默认的指示器

        expanableListview.setGroupIndicator(null);

        cartPresenter = new CartPresenter(this);

        gson = new Gson();

        //全选:...点击事件

        check_all.setOnClickListener(this);

    }

    @Override

    protected void onResume() {

        super.onResume();

        //请求数据

        cartPresenter.getCartData(cartUrl);

    }

    @Override

    public void getSuccessCartData(String json) {

        //解析数据

        CartBean cartBean = gson.fromJson(json, CartBean.class);

        //一个是一级标题的数据

        List<CartBean.DataBean> listGroup = cartBean.getData();

        //所有子条目的数据

        List<List<CartBean.DataBean.ListBean>> listChilds = new ArrayList<>();

        for (int i=0;i<listGroup.size();i++){

            listChilds.add(listGroup.get(i).getList());

        }

        //设置适配器

        myAdapter = new MyAdapter(MainActivity.this, listGroup, listChilds,handler);

        expanableListview.setAdapter(myAdapter);

        //展开所有

        for (int i=0;i<listGroup.size();i++){

            expanableListview.expandGroup(i);

        }

    }

    @Override

    public void onClick(View view) {

        switch (view.getId()){

            case R.id.check_all:

                myAdapter.setIfCheckAll(check_all.isChecked());

                break;

        }

    }

}