本文实例为大家分享了android实现简单购物车的具体代码，供大家参考，具体内容如下
这里我用到的都是android自带sdk中的资源，做了一个极其简单的购物车实现，总结购物车难点包含两个方面:
1、checkbox的联动:
全选框、商铺复选框以及商品复选框要做到滴水不漏的联动，我的经验是在监听多选框时尽量采用click事件，避免使用checkchange事件（因为它总是能在你意想不到的地方调用），全选框可以通过商品价格来判断，这个在代码中也有体现。
2、数据的联动和ui的联动:
适配器的都是在外部类创建，而总价格等控件都是在调用适配器的地方，这个要做到联动，最简单的方式必然就是接口的回调，熟练使用可以节省很多代码，提高编程效率。
再有一个比较容易出现问题的地方就在于，我们经常是首先更改数据，然后通知适配器刷新数据（notifydatasetchanged()），这里要注意的一点就是在更新数据的时候，一定确保更新的传递到适配器中的数据集合，否则会发现这个更新适配器的方法是无效的。
其他相关问题代码中均有体现，如果和我一样是一个编程小白，仔细阅读会有收获滴。
代码中没有添加自己的资源，逻辑都有实现就是ui丑了一点
activity_main:
<?xml version="1.0" encoding="utf-8"?> <linearlayout android:orientation="vertical" xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.bwie.test.test1025two.mainactivity"> <relativelayout android:layout_gravity="center_horizontal" android:background="@color/coloraccent" android:layout_width="match_parent" android:layout_height="50dp"> <textview android:textsize="38sp" android:gravity="center" android:textcolor="#fff" android:text="购物车" android:layout_width="match_parent" android:layout_height="wrap_content" /> <textview android:textcolor="#fff" android:textsize="38sp" android:layout_alignparentright="true" android:text="2" android:id="@+id/main_num" android:layout_width="wrap_content" android:layout_height="wrap_content" /> </relativelayout> <expandablelistview android:layout_weight="1" android:id="@+id/expand_able_view" android:layout_width="match_parent" android:layout_height="match_parent"/> <linearlayout android:layout_width="match_parent" android:layout_height="wrap_content"> <checkbox android:layout_weight="1" android:id="@+id/main_check_all" android:text="全选" android:layout_width="0dp" android:layout_height="wrap_content" /> <textview android:id="@+id/main_price" android:gravity="center_horizontal" android:text="0" android:layout_weight="1" android:layout_width="0dp" android:layout_height="wrap_content" /> <button android:id="@+id/btn_delete" android:background="#aaa" android:layout_weight="1" android:text="删除" android:layout_width="0dp" android:layout_height="wrap_content" /> <button android:id="@+id/btn_buy" android:background="#f99" android:layout_weight="1" android:text="购买" android:layout_width="0dp" android:layout_height="wrap_content" /> </linearlayout> </linearlayout>
group_item:
注:这里图了个简单，商铺名称我是通过设置checkbox的text来显示的，另外取消焦点是为了不影响二级列表的点击展开与收回子集列表
<?xml version="1.0" encoding="utf-8"?> <linearlayout android:orientation="horizontal" xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent"> <checkbox android:focusable="false" android:id="@+id/group_check" android:layout_width="wrap_content" android:layout_height="wrap_content" /> </linearlayout>
child_item:
<?xml version="1.0" encoding="utf-8"?> <linearlayout android:orientation="horizontal" xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent"> <checkbox android:id="@+id/child_check" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <imageview android:id="@+id/child_img" android:scaletype="center" android:src="@mipmap/ic_launcher" android:layout_width="80dp" android:layout_height="80dp" /> <textview android:id="@+id/child_price" android:textsize="22sp" android:textcolor="@color/colorprimary" android:text="2888" android:layout_width="wrap_content" android:layout_height="80dp" /> <relativelayout android:layout_weight="1" android:layout_width="match_parent" android:layout_height="80dp"> <textview android:text="名字" android:id="@+id/child_name" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <linearlayout android:orientation="horizontal" android:layout_alignparentbottom="true" android:layout_width="wrap_content" android:layout_height="wrap_content"> <textview android:id="@+id/child_jian" android:gravity="center_horizontal" android:text="—" android:layout_width="30dp" android:layout_height="30dp" /> <textview android:gravity="center_horizontal" android:text="2" android:id="@+id/child_num" android:layout_width="30dp" android:layout_height="30dp" /> <textview android:id="@+id/child_jia" android:gravity="center_horizontal" android:text="+" android:layout_width="30dp" android:layout_height="30dp" /> </linearlayout> </relativelayout> </linearlayout>
groupbean:
package com.bwie.test.test1025two;
import java.util.arraylist;
/**
* created by zzw on 2017/10/25.
*/
public class group {
private string name;
private boolean check;
private arraylist<child> children;
public group(string name, boolean check,arraylist<child> children) {
this.name = name;
this.check = check;
this.children = children;
}
public group() {
}
public string getname() {
return name;
}
public void setname(string name) {
this.name = name;
}
public boolean ischeck() {
return check;
}
public void setcheck(boolean check) {
this.check = check;
}
public void setchildren(arraylist<child> children){
this.children = children;
}
public arraylist<child> getchildren(){
return children;
}
@override
public string tostring() {
return "group{" +
"name='" + name + '\'' +
", check=" + check +
'}';
}
}
childbean:
package com.bwie.test.test1025two;
/**
* created by zzw on 2017/10/25.
*/
public class child {
private string name;
private string img;
private int num;
private boolean check;
private int price;
public child(string name, string img, int num, boolean check, int price) {
this.name = name;
this.img = img;
this.num = num;
this.check = check;
this.price = price;
}
public child() {
}
public string getname() {
return name;
}
public void setname(string name) {
this.name = name;
}
public string getimg() {
return img;
}
public void setimg(string img) {
this.img = img;
}
public int getnum() {
return num;
}
public void setnum(int num) {
this.num = num;
}
public boolean ischeck() {
return check;
}
public void setcheck(boolean check) {
this.check = check;
}
public int getprice() {
return price;
}
public void setprice(int price) {
this.price = price;
}
@override
public string tostring() {
return "child{" +
"name='" + name + '\'' +
", img='" + img + '\'' +
", num=" + num +
", check=" + check +
", price=" + price +
'}';
}
}
myadapter:
package com.bwie.test.test1025two;
import android.content.context;
import android.view.layoutinflater;
import android.view.view;
import android.view.viewgroup;
import android.widget.baseexpandablelistadapter;
import android.widget.checkbox;
import android.widget.imageview;
import android.widget.textview;
import java.util.arraylist;
/**
* created by zzw on 2017/10/25.
*/
public class myadapter extends baseexpandablelistadapter {
context context;
arraylist<group> groups;
public myadapter(context context, arraylist<group> groups) {
this.context = context;
this.groups = groups;
}
//监听加减事件回调接口
public interface onnumchangelistener{
void onnumchange(int groupid,int childid,boolean isadd);
}
private onnumchangelistener monnumchangelistener;
public void setonnumchangelistener(onnumchangelistener monnumchangelistener){
this.monnumchangelistener = monnumchangelistener;
}
//监听多选框点击事件回调接口。
public interface oncheckchangelistener{
void ongroupclick(int groupid);
void onchildclick(int groupid,int childid);
}
private oncheckchangelistener moncheckchangelistener;
public void setmoncheckchangelistener(oncheckchangelistener moncheckchangelistener){
this.moncheckchangelistener = moncheckchangelistener;
}
//监听价格需要更新回调接口
public interface onshouldchangemoneylistener{
void onshouldchnagemoney();
}
private onshouldchangemoneylistener monshouldchangemoneylistener;
public void setmonshouldchangemoneylistener(onshouldchangemoneylistener monshouldchangemoneylistener){
this.monshouldchangemoneylistener = monshouldchangemoneylistener;
}
@override
public int getgroupcount() {
return groups.size();
}
@override
public int getchildrencount(int i) {
return groups.get(i).getchildren().size();
}
@override
public object getgroup(int i) {
return groups.get(i);
}
@override
public object getchild(int i, int i1) {
return groups.get(i).getchildren().get(i1);
}
@override
public long getgroupid(int i) {
return i;
}
@override
public long getchildid(int i, int i1) {
return i1;
}
@override
public boolean hasstableids() {
return false;
}
@override
public view getgroupview(final int i, boolean b, view view, viewgroup viewgroup) {
groupholder holder = null;
if (view == null){
view = layoutinflater.from(context).inflate(r.layout.group_item,viewgroup,false);
holder = new groupholder();
holder.checkbox = (checkbox) view.findviewbyid(r.id.group_check);
view.settag(holder);
}else{
holder = (groupholder) view.gettag();
}
holder.checkbox.settext(groups.get(i).getname());
holder.checkbox.setchecked(groups.get(i).ischeck());
if (moncheckchangelistener != null&&monshouldchangemoneylistener != null){
holder.checkbox.setonclicklistener(new view.onclicklistener() {
@override
public void onclick(view view) {
moncheckchangelistener.ongroupclick(i);
monshouldchangemoneylistener.onshouldchnagemoney();
}
});
}
return view;
}
@override
public view getchildview(final int i,final int i1, boolean b, view view, viewgroup viewgroup) {
childholder holder = null;
if (view == null){
view = layoutinflater.from(context).inflate(r.layout.child_item,viewgroup,false);
holder = new childholder();
holder.checkbox = (checkbox) view.findviewbyid(r.id.child_check);
holder.imageview = (imageview) view.findviewbyid(r.id.child_img);
holder.name = (textview) view.findviewbyid(r.id.child_name);
holder.num = (textview) view.findviewbyid(r.id.child_num);
holder.jian = (textview) view.findviewbyid(r.id.child_jian);
holder.jia = (textview) view.findviewbyid(r.id.child_jia);
holder.price = (textview) view.findviewbyid(r.id.child_price);
view.settag(holder);
}else{
holder = (childholder) view.gettag();
}
holder.checkbox.setchecked(groups.get(i).getchildren().get(i1).ischeck());
holder.imageview.setimageresource(r.mipmap.ic_launcher);
holder.name.settext(groups.get(i).getchildren().get(i1).getname());
holder.num.settext(groups.get(i).getchildren().get(i1).getnum()+"");
holder.price.settext(groups.get(i).getchildren().get(i1).getprice()+"");
if (monnumchangelistener != null&&monshouldchangemoneylistener != null){
holder.jian.setonclicklistener(new view.onclicklistener() {
@override
public void onclick(view view) {
monnumchangelistener.onnumchange(i,i1,false);
monshouldchangemoneylistener.onshouldchnagemoney();
}
});
}
if (monnumchangelistener != null&&monshouldchangemoneylistener != null){
holder.jia.setonclicklistener(new view.onclicklistener() {
@override
public void onclick(view view) {
monnumchangelistener.onnumchange(i,i1,true);
monshouldchangemoneylistener.onshouldchnagemoney();
}
});
}
if (moncheckchangelistener != null&&monshouldchangemoneylistener != null){
holder.checkbox.setonclicklistener(new view.onclicklistener() {
@override
public void onclick(view view) {
moncheckchangelistener.onchildclick(i,i1);
monshouldchangemoneylistener.onshouldchnagemoney();
}
});
}
return view;
}
@override
public boolean ischildselectable(int i, int i1) {
return true;
}
class groupholder {
checkbox checkbox;
}
class childholder{
checkbox checkbox;
imageview imageview;
textview name,num,jian,jia,price;
}
}
mainactivity:
package com.bwie.test.test1025two;
import android.os.bundle;
import android.support.v7.app.appcompatactivity;
import android.view.view;
import android.widget.button;
import android.widget.checkbox;
import android.widget.expandablelistview;
import android.widget.textview;
import android.widget.toast;
import java.util.arraylist;
import java.util.list;
public class mainactivity extends appcompatactivity {
textview num,price;//右上角当前商品数量和底部当前已选中商品的价格
expandablelistview expandablelistview;//展示商品信息的二级列表
checkbox checkall;//左下角全选
button btndel,btnbuy;//底部删除当前选中按钮、购买按钮
arraylist<group> groups = new arraylist<>();//数据源集合
myadapter adapter;//自定义baseexpandable适配器
@override
protected void oncreate(bundle savedinstancestate) {
super.oncreate(savedinstancestate);
setcontentview(r.layout.activity_main);
initview();//控件初始化
initdata();//数据初始化
changegoodsnum();//初始化当前商品个数。
/**
* 自定义加减按钮回调
* params: groupid:商铺id childid:商品在当前商铺的id isadd:非加即减
*/
adapter.setonnumchangelistener(new myadapter.onnumchangelistener() {
@override
public void onnumchange(int groupid, int childid, boolean isadd) {
//获得当前点击商品的数量
int num = groups.get(groupid).getchildren().get(childid).getnum();
if (isadd){//加
//在数据源中该商品数量自增1
groups.get(groupid).getchildren().get(childid).setnum(++num);
}else{//减
if (num == 1){//数量为1给出提示
toast.maketext(mainactivity.this, "受不了了，不能再少了", toast.length_short).show();
}else{//在数据源中该商品数量自减1
groups.get(groupid).getchildren().get(childid).setnum(--num);
}
}
//更新ui
adapter.notifydatasetchanged();
changemoney();//更新价格显示
}
});
//自定义商铺和商品多选框点击回调
adapter.setmoncheckchangelistener(new myadapter.oncheckchangelistener() {
@override
public void ongroupclick(int groupid) {//组点击
//将数据源置反，以保持同步
groups.get(groupid).setcheck(!(groups.get(groupid).ischeck()));
//获取当前选中状态
boolean flag = groups.get(groupid).ischeck();
//更新其下所有商品checkbox
for (int i = 0 ; i < groups.get(groupid).getchildren().size(); i++){
groups.get(groupid).getchildren().get(i).setcheck(flag);
}
//更新ui
adapter.notifydatasetchanged();
//更新价格显示
changemoney();
}
@override
public void onchildclick(int groupid, int childid) {//商品点击
//将数据源置反以保持同步
groups.get(groupid).getchildren().get(childid).setcheck(!(groups.get(groupid).getchildren().get(childid).ischeck()));
//判断该条目及所有兄弟条目是否全部选中，以及时更新商铺checkbox
int flag = 0;
for (int i = 0 ; i < groups.get(groupid).getchildren().size() ; i++){
if (groups.get(groupid).getchildren().get(i).ischeck()){
flag++;
}
}
//如果该组下的选中数量与该集合长度相等，说明全部选中，更新组checkbox
if (flag == groups.get(groupid).getchildren().size()){
groups.get(groupid).setcheck(true);
}else{
groups.get(groupid).setcheck(false);
}
//更新ui
adapter.notifydatasetchanged();
//更新价格显示
changemoney();
}
});
//删除按钮点击
btndel.setonclicklistener(new view.onclicklistener() {
@override
public void onclick(view view) {
list<group> tobedeletegroups = new arraylist<group>();// 待删除的组元素列表
for (int i = 0; i < groups.size(); i++) {
group group = groups.get(i);
if (group.ischeck()) {
tobedeletegroups.add(group);
}
list<child> tobedeletechildren = new arraylist<child>();// 待删除的子元素列表
list<child> childs = group.getchildren();
for (int j = 0; j < childs.size(); j++) {
if (childs.get(j).ischeck()) {
tobedeletechildren.add(childs.get(j));
}
}
childs.removeall(tobedeletechildren);
}
groups.removeall(tobedeletegroups);
//更新ui
adapter.notifydatasetchanged();
//更新当前商品数量显示
changegoodsnum();
//更新当前价格显示
changemoney();
}
});
//购买按钮，点击提示当前选中金额
btnbuy.setonclicklistener(new view.onclicklistener() {
@override
public void onclick(view view) {
string money = price.gettext().tostring();
toast.maketext(mainactivity.this, "当前总金额:"+money, toast.length_short).show();
}
});
//全选按钮，点击更新视图所有checkbox
checkall.setonclicklistener(new view.onclicklistener() {
@override
public void onclick(view view) {
for (int i = 0 ; i< groups.size() ; i++){
groups.get(i).setcheck(checkall.ischecked());
for (int j = 0 ; j < groups.get(i).getchildren().size() ; j ++){
groups.get(i).getchildren().get(j).setcheck(checkall.ischecked());
}
}
//更新ui
adapter.notifydatasetchanged();
//更新总价显示
changemoney();
}
});
//自定义回调更新总价
adapter.setmonshouldchangemoneylistener(new myadapter.onshouldchangemoneylistener() {
@override
public void onshouldchnagemoney() {
//更新总价显示
changemoney();
}
});
}
//初始化数据，设置适配器
private void initdata() {
for (int i = 0 ; i < 5 ; i++){
arraylist<child> children = new arraylist<>();
for (int j = 0 ; j <= i ; j++){
children.add(new child("店铺"+i+"的商品:"+j,"",2,false,j+1));
}
groups.add(new group("商铺:"+i,false,children));
}
adapter = new myadapter(this,groups);
expandablelistview.setadapter(adapter);
for (int i = 0; i < groups.size(); i++)
{
expandablelistview.expandgroup(i);// 初始化时，将expandablelistview以展开的方式呈现
}
}
//获得控件资源
private void initview() {
num = (textview) findviewbyid(r.id.main_num);
expandablelistview = (expandablelistview) findviewbyid(r.id.expand_able_view);
checkall = (checkbox) findviewbyid(r.id.main_check_all);
btndel = (button) findviewbyid(r.id.btn_delete);
btnbuy = (button) findviewbyid(r.id.btn_buy);
price = (textview) findviewbyid(r.id.main_price);
}
//当前购物车商品数量
private void changegoodsnum(){
int currentnum = 0;
for (int i = 0 ; i < groups.size(); i++){
for (int j = 0 ; j < groups.get(i).getchildren().size(); j++){
currentnum++;
}
}
num.settext(currentnum+"");
}
//更新总价
private void changemoney(){
int money = 0;
int allmoney = 0;//获得当前全部商品价格
for (int i = 0 ; i < groups.size(); i++){
for (int j = 0 ; j < groups.get(i).getchildren().size(); j++){
if (groups.get(i).getchildren().get(j).ischeck()){
money += groups.get(i).getchildren().get(j).getnum() * groups.get(i).getchildren().get(j).getprice();
}
allmoney += groups.get(i).getchildren().get(j).getnum() * groups.get(i).getchildren().get(j).getprice();
}
}
//当选中价格与全部价格相等，更新全选框
if (money == allmoney){
checkall.setchecked(true);
}else{
checkall.setchecked(false);
}
price.settext(money + "");
}
}
效果图:
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