Android实现购物车整体页面逻辑详解

public class mainactivity extends appcompatactivity implements view.onclicklistener{

  string url = "http://www.zhaoapi.cn/product/getcarts";
  private expandablelistview el_cart;
  private checkbox cb_cart_all_select;
  private textview tv_cart_total_price;
  private button btn_cart_pay;
  myadapter adapter;
  @override
  protected void oncreate(bundle savedinstancestate) {
    super.oncreate(savedinstancestate);
    setcontentview(r.layout.activity_main);

    initview();
    initdata();
  }

  private void initdata() {

    hashmap<string, string> map = new hashmap<>();
    map.put("uid","71");
    okhtttputils.getinstance().dopost(url, map, new okhtttputils.okcallback() {
      @override
      public void onfailure(exception e) {

      }

      @override
      public void onresponse(string json) {

        cartinfo cartinfo = new gson().fromjson(json, cartinfo.class);
        if ("0".equals(cartinfo.getcode())){
          list<cartinfo.databean> data = cartinfo.getdata();
          adapter = new myadapter(data);
          el_cart.setadapter(adapter);

          //展开二级列表
          for(int x=0; x<data.size(); x++){
            el_cart.expandgroup(x);
          }

          adapter.setoncartlistchangelistener(new myadapter.oncartlistchangelistener() {
            @override
            public void onsellercheckedchange(int i) {

              //商家被点击
              boolean currentsellerallproductselected = adapter.iscurrentsellerallproductselected(i);
              adapter.changecurrentsellerallproductsstatus(i, !currentsellerallproductselected);
              adapter.notifydatasetchanged();
              //b.刷新底部数据
              refreshselectedandtotalpriceandtotalnumber();
            }

            @override
            public void onproductcheckedchange(int i, int i1) {

              //点击商品得checkbox
              adapter.changecurrentproductstatus(i,i1);
              adapter.notifydatasetchanged();
              //b.刷新底部数据
              refreshselectedandtotalpriceandtotalnumber();
            }

            @override
            public void onproducnumberchange(int i, int i1, int number) {

              //当加减被点击
              adapter.changecurrentproductnumber(i,i1,number);
              adapter.notifydatasetchanged();
              //b.刷新底部数据
              refreshselectedandtotalpriceandtotalnumber();
            }
          });
        }
      }
    });
  }

  //b.刷新checkbox状态和总价和总数量
  private void refreshselectedandtotalpriceandtotalnumber() {
    //去判断是否所有得商品都被选中
    boolean allproductsselected = adapter.isallproductsselected();
    //设置给全选checkbox
    cb_cart_all_select.setchecked(allproductsselected);

    //计算总价
    float totalprice = adapter.calculatetotalprice();
    tv_cart_total_price.settext("总价 " + totalprice);

    //计算总数量
    int totalnumber = adapter.calculatetotalnumber();
    btn_cart_pay.settext("去结算(" + totalnumber + ")");
  }

  //初始化的操作
  private void initview() {
    el_cart = (expandablelistview) findviewbyid(r.id.el_cart);
    cb_cart_all_select = (checkbox) findviewbyid(r.id.cb_cart_all_select);
    tv_cart_total_price = (textview) findviewbyid(r.id.tv_cart_total_price);
    btn_cart_pay = (button) findviewbyid(r.id.btn_cart_pay);

    cb_cart_all_select.setonclicklistener(this);
  }

  @override
  public void onclick(view view) {

    switch (view.getid()){
      case r.id.cb_cart_all_select:

        //底部全选按钮
        //时候所有得商品都被选中
        boolean allproductsselected = adapter.isallproductsselected();
        adapter.changeallproductstatus(!allproductsselected);
        adapter.notifydatasetchanged();
        //刷新底部数据
        refreshselectedandtotalpriceandtotalnumber();
        break;
    }
  }
}

public class myadapter extends baseexpandablelistadapter{

  private list<cartinfo.databean> list;
  public myadapter(list<cartinfo.databean> data) {
    list=data;
  }

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

  @override
  public int getchildrencount(int i) {
    return list.get(i).getlist()==null ? 0 :list.get(i).getlist().size();
  }

  @override
  public view getgroupview(final int i, boolean b, view view, viewgroup viewgroup) {

    //先拿到bean里组的数据,看hijson
    cartinfo.databean databean = list.get(i);
    parentviewholder parentviewholder;
    if (view == null) {
      view = view.inflate(viewgroup.getcontext(), r.layout.item_cart_parent, null);
      parentviewholder = new parentviewholder(view);
      view.settag(parentviewholder);
    } else {
      parentviewholder = (parentviewholder) view.gettag();
    }
    parentviewholder.seller_name_tv.settext(databean.getsellername());

    boolean currentsellerallproductselected = iscurrentsellerallproductselected(i);
    parentviewholder.seller_cb.setchecked(currentsellerallproductselected);

    //d.设置点击checkbox
    parentviewholder.seller_cb.setonclicklistener(new view.onclicklistener() {
      @override
      public void onclick(view v) {
        if (moncartlistchangelistener !=null){
          moncartlistchangelistener.onsellercheckedchange(i);
        }
      }
    });
    return view;
  }


  @override
  public view getchildview(final int i, final int i1, boolean b, view view, viewgroup viewgroup) {

    cartinfo.databean databean = list.get(i);
    list<cartinfo.databean.listbean> list1 = databean.getlist();
    cartinfo.databean.listbean listbean = list1.get(i1);
    childviewholder childviewholder;


    if (view == null) {
      view = view.inflate(viewgroup.getcontext(), r.layout.item_cart_child, null);
      childviewholder = new childviewholder(view);
      view.settag(childviewholder);
    } else {
      childviewholder=(childviewholder)view.gettag();
    }
    //设置商品名字
    childviewholder.product_title_name_tv.settext(listbean.gettitle());
    //设置商品单价
    childviewholder.product_price_tv.settext(listbean.getprice()+"");
    //设置复选框是否选中
    childviewholder.child_cb.setchecked(listbean.getselected() == 1);

    //设置组合式自定义控件内部的数量
    childviewholder.add_remove_view.setnumber(listbean.getnum());

    //d.设置商品checkbox的点击事件,通过接口回调,暴露给外面
    childviewholder.child_cb.setonclicklistener(new view.onclicklistener() {
      @override
      public void onclick(view v) {
        if (moncartlistchangelistener != null){
          moncartlistchangelistener.onproductcheckedchange(i,i1);
        }
      }
    });

    //d.设置商品数量的点击事件,通过接口回调,暴露给外面
    childviewholder.add_remove_view.setonnumberchangelistener(new addsubview.onnumberchangelistener() {
      @override
      public void onnumberchange(int num) {
        if (moncartlistchangelistener !=null){
          moncartlistchangelistener.onproducnumberchange(i,i1,num);
        }
      }
    });
    return view;
  }

  public boolean iscurrentsellerallproductselected(int i){//根据商品改变商家--如果商品全部选中商家则选中--有一个商品没选中则商家不选中
    cartinfo.databean databean = list.get(i);
    list<cartinfo.databean.listbean> beans = databean.getlist();
    for (cartinfo.databean.listbean bean : beans){

      if (bean.getselected()==0){
        return false;
      }

    }
        return true;
  }

  public boolean isallproductsselected(){ //根据商品改变全选--如果商品全部选中全选则选中--有一个商品没选中则全选不选中
    for (int x=0;x<list.size();x++){
      cartinfo.databean databean = list.get(x);
      list<cartinfo.databean.listbean> list1 = databean.getlist();
      for (int j=0;j<list1.size();j++){
        if (list1.get(j).getselected()==0){
          return false;
        }
      }
    }
    return true;
  }

  public int calculatetotalnumber(){ //计算总数量
    int totalnumber=0;
    for (int i=0;i<list.size();i++){
      cartinfo.databean databean = list.get(i);
      list<cartinfo.databean.listbean> list1 = databean.getlist();
      for (int j=0;j<list1.size();j++){
        if (list1.get(j).getselected()==1){
          int num = list1.get(j).getnum();

          totalnumber+=num;
        }
      }
    }

    return totalnumber;
  }


  public float calculatetotalprice(){ //获取总价
    float totalprice=0;
    for (int i=0;i<list.size();i++){
      cartinfo.databean databean = list.get(i);
      list<cartinfo.databean.listbean> list = databean.getlist();
      for (int j=0;j<list.size();j++){
        if (list.get(j).getselected()==1){
          float price = list.get(j).getprice();
          int num = list.get(j).getnum();
          totalprice+=price*num;
        }
      }
    }
    return totalprice;
  }
  //c.当商品组的全选框点击时,更新所有商品的状态
  public void changecurrentsellerallproductsstatus(int i,boolean isselected){

    cartinfo.databean databean = list.get(i);
    list<cartinfo.databean.listbean> beans = databean.getlist();
    for (int j=0;j<beans.size();j++){
      cartinfo.databean.listbean bean = beans.get(j);
      bean.setselected(isselected ?1 :0);
    }
  }

  //c.当商家子条目的全选框选中时,更新其状态
  public void changecurrentproductstatus(int i , int i1){
    cartinfo.databean databean = list.get(i);
    list<cartinfo.databean.listbean> list = databean.getlist();
    cartinfo.databean.listbean listbean = list.get(i1);
    listbean.setselected(listbean.getselected() == 0 ? 1 : 0 );

  }
  //c.设置所有商品的状态
  public void changeallproductstatus(boolean selected){
    for(int x=0; x<list.size() ; x++){
      cartinfo.databean databean = list.get(x);
      list<cartinfo.databean.listbean> list = databean.getlist();
      for(int j=0; j<list.size(); j++){
        list.get(j).setselected(selected ? 1 : 0);
      }
    }
  }

  //c.当加减器被点击时,调用,改变里面当前商品的数量 参数1定位那个商家  参数2定位哪个商品 参数3定位改变具体的数量是多少
  public void changecurrentproductnumber(int i,int i1,int number){
    cartinfo.databean databean = list.get(i);
    list<cartinfo.databean.listbean> list = databean.getlist();
    cartinfo.databean.listbean listbean = list.get(i1);
    listbean.setnum(number);
  }

  public interface oncartlistchangelistener{
    /**
     * 当商家的checkbox点击时回调
     */
    void onsellercheckedchange(int i);

    /**
     * 当点击子条目商品的checkbox回调
     */
    void onproductcheckedchange(int i ,int i1);

    /**
     * 当点击加减按钮的回调
     */
    void onproducnumberchange(int i , int i1 , int number);

  }
  //d.
  oncartlistchangelistener moncartlistchangelistener;
  //d.
  public void setoncartlistchangelistener(oncartlistchangelistener oncartlistchangelistener){
    moncartlistchangelistener = oncartlistchangelistener ;
  }

  public static class parentviewholder {
    public checkbox seller_cb;
    public textview seller_name_tv;

    public parentviewholder(view rootview) {
      this.seller_cb = (checkbox) rootview.findviewbyid(r.id.seller_cb);
      this.seller_name_tv = (textview) rootview.findviewbyid(r.id.seller_name_tv);
    }
  }

  public static class childviewholder {
    public checkbox child_cb;
    public imageview product_icon_iv;
    public textview product_title_name_tv;
    public textview product_price_tv;
    public addsubview add_remove_view;

    public childviewholder(view rootview) {
      this.child_cb = (checkbox) rootview.findviewbyid(r.id.child_cb);
      this.product_icon_iv = (imageview) rootview.findviewbyid(r.id.product_icon_iv);
      this.product_title_name_tv = (textview) rootview.findviewbyid(r.id.product_title_name_tv);
      this.product_price_tv = (textview) rootview.findviewbyid(r.id.product_price_tv);
      this.add_remove_view = (addsubview) rootview.findviewbyid(r.id.add_remove_view);
    }
  }

  @override
  public object getgroup(int i) {
    return null;
  }

  @override
  public object getchild(int i, int i1) {
    return null;
  }

  @override
  public long getgroupid(int i) {
    return 0;
  }

  @override
  public long getchildid(int i, int i1) {
    return 0;
  }

  @override
  public boolean hasstableids() {
    return false;
  }


  @override
  public boolean ischildselectable(int i, int i1) {
    return false;
  }
}

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent">

  <expandablelistview
    android:id="@+id/el_cart"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginbottom="60dp" />

  <linearlayout
    android:layout_width="match_parent"
    android:layout_height="60dp"
    android:layout_alignparentbottom="true"
    android:background="#eeeeee"
    android:gravity="center_vertical">

    <checkbox
      android:id="@+id/cb_cart_all_select"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content" />

    <textview
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="全选" />

    <textview
      android:id="@+id/tv_cart_total_price"
      android:layout_width="0dp"
      android:layout_height="wrap_content"
      android:layout_weight="1"
      android:paddingleft="20dp"
      android:text="合计:¥0.00" />

    <button
      android:id="@+id/btn_cart_pay"
      android:layout_width="100dp"
      android:layout_height="match_parent"
      android:text="去结算(0)" />
  </linearlayout>

</relativelayout>

public class addsubview extends linearlayout implements view.onclicklistener{  //组合式控件
  private int number = 1;
  private textview sub_tv;
  private textview product_number_tv;
  private textview add_tv;

  public addsubview(context context) {
    this(context,null);
  }

  public addsubview(context context, @nullable attributeset attrs) {
    this(context, attrs,0);
  }

  public addsubview(context context, @nullable attributeset attrs, int defstyleattr) {
    super(context, attrs, defstyleattr);

    view view = inflate(context, r.layout.add_remove, this);

    sub_tv=view.findviewbyid(r.id.sub_tv);
    product_number_tv=view.findviewbyid(r.id.product_number_tv);
    add_tv=view.findviewbyid(r.id.add_tv);


    sub_tv.setonclicklistener(this);
    add_tv.setonclicklistener(this);
  }

  @override
  public void onclick(view view) {
    switch (view.getid()){

      case r.id.sub_tv:

        if (number>1){
          --number;
          product_number_tv.settext(number+"");
          if (onnumberchangelistener!=null){
            onnumberchangelistener.onnumberchange(number);
          }
        }else {
          toast.maketext(getcontext(), "不能再少了", toast.length_short).show();
        }
        break;

      case r.id.add_tv:

        if (number<8){
          ++number;
          product_number_tv.settext(number+"");
          if (onnumberchangelistener!=null){
            onnumberchangelistener.onnumberchange(number);
          }
        }else {
          toast.maketext(getcontext(), "不能再多了", toast.length_short).show();
        }
        break;
    }
  }

  public int getnumber() {
    return number;
  }

  public void setnumber(int number) {
    this.number = number;
    product_number_tv.settext(number + "");
  }

  onnumberchangelistener onnumberchangelistener;

  public void setonnumberchangelistener(onnumberchangelistener onnumberchangelistener) {
    this.onnumberchangelistener = onnumberchangelistener;
  }

  interface onnumberchangelistener {
    void onnumberchange(int num);
  }
}

<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:padding="2dp"
  android:layout_marginleft="10dp"
  android:layout_width="60dp"
  android:layout_height="30dp"
  android:layout_gravity="center_vertical"
  android:background="#99000000"
  android:gravity="center_vertical">

  <textview
    android:background="#ffffff"
    android:layout_weight="1"
    android:id="@+id/sub_tv"
    android:layout_width="0dp"
    android:layout_height="match_parent"
    android:gravity="center"
    android:text="-"
    android:textsize="16sp" />

  <textview
    android:text="1"
    android:layout_marginleft="2dp"
    android:background="#ffffff"
    android:layout_weight="1"
    android:id="@+id/product_number_tv"
    android:layout_width="0dp"
    android:layout_height="match_parent"
    android:gravity="center"
    />

  <textview
    android:layout_marginleft="2dp"
    android:background="#ffffff"
    android:layout_weight="1"
    android:id="@+id/add_tv"
    android:layout_width="0dp"
    android:layout_height="match_parent"
    android:gravity="center"
    android:text="+"
    android:textsize="16sp" />

</linearlayout>

<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"   //商家条目
  android:layout_width="match_parent"
  android:layout_height="60dp"
  android:gravity="center_vertical"
  >


  <checkbox
    android:id="@+id/seller_cb"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

  <textview
    android:id="@+id/seller_name_tv"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginleft="20dp" />
</linearlayout>

<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="120dp"
  android:gravity="center_vertical">

  <checkbox
    android:id="@+id/child_cb"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

  <imageview
    android:id="@+id/product_icon_iv"
    android:layout_width="80dp"
    android:layout_height="80dp"
    android:layout_marginleft="20dp"
    android:scaletype="centercrop"
    android:src="@color/colorprimary" />

  <linearlayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:orientation="vertical">

    <textview
      android:id="@+id/product_title_name_tv"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:ellipsize="end"
      android:maxlines="2"
      android:text="商品标题" />

    <textview
      android:id="@+id/product_price_tv"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_margintop="10dp"
      android:text="¥0.0" />
  </linearlayout>

  <fanruiqi.bwie.com.shopcat.addsubview
    android:id="@+id/add_remove_view"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginright="10dp" />
</linearlayout>

public class okhtttputils {
  private static okhtttputils mokhtttputils;
  private okhttpclient mokhttpclien;
  private final handler mhandler;

  private okhtttputils() {

    //创建一个主线程的handler
    mhandler = new handler(looper.getmainlooper());
    mokhttpclien = new okhttpclient.builder()
        .connecttimeout(5000, timeunit.milliseconds)
        .readtimeout(5000, timeunit.milliseconds)
        .writetimeout(5000, timeunit.milliseconds)
        .build();
  }

  //单例模式
  public static okhtttputils getinstance() {
    if (mokhtttputils == null) {
      synchronized (okhtttputils.class) {
        if (mokhtttputils == null) {
          return mokhtttputils = new okhtttputils();
        }
      }
    }
    return mokhtttputils;
  }

  public interface okcallback {
    void onfailure(exception e);
    void onresponse(string json);
  }


  public void dopost(string url, map<string, string> map, final okcallback okcallback) {
    //创建formbody的对象,把表单添加到formbody中
    formbody.builder builder = new formbody.builder();
    if (map != null) {
      for (string key : map.keyset()) {
        builder.add(key, map.get(key));
      }
    }
    formbody formbody = builder.build();

    //创建request对象
    request request = new request.builder()
        .post(formbody)
        .url(url)
        .build();
    //创建call对象
    final call call = mokhttpclien.newcall(request);
    call.enqueue(new callback() {
      @override
      public void onfailure(call call, final ioexception e) {
        if (okcallback != null) {
          //切换到主线程
          mhandler.post(new runnable() {
            @override
            public void run() {
              okcallback.onfailure(e);
            }
          });
        }
      }
      @override
      public void onresponse(call call, final response response) throws ioexception {
        try {
          if (response != null && response.issuccessful()) {
            final string json = response.body().string();
            mhandler.post(new runnable() {
              @override
              public void run() {
                if (okcallback != null) {
                  okcallback.onresponse(json);
                  return;
                }
              }
            });
          }
        } catch (ioexception e) {
          e.printstacktrace();
        }
        if (okcallback != null) {
          okcallback.onfailure(new exception("网络异常"));
        }
      }
    });
  }




  //封装doget的网络请求
  public void doget(string url, final okcallback okcallback) {
    request request = new request.builder()
        .get()
        .url(url)
        .build();

    final call call = mokhttpclien.newcall(request);
    call.enqueue(new callback() {
      @override
      public void onfailure(call call, final ioexception e) {
        if (okcallback != null) {
          //切换到主线程
          mhandler.post(new runnable() {
            @override
            public void run() {
              okcallback.onfailure(e);
            }
          });
        }
      }

      @override
      public void onresponse(call call, final response response) throws ioexception {

        try {
          if (response != null && response.issuccessful()) {
            final string json = response.body().string();
            mhandler.post(new runnable() {
              @override
              public void run() {
                if (okcallback != null) {
                  okcallback.onresponse(json);
                  return;
                }

              }
            });
          }
        } catch (ioexception e) {
          e.printstacktrace();
        }

      }
    });
  }

}