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這篇文章主要介紹“Android如何實現簡單購物車”，在日常操作中，相信很多人在Android如何實現簡單購物車問題上存在疑惑，小編查閱了各式資料，整理出簡單好用的操作方法，希望對大家解答”Android如何實現簡單購物車”的疑惑有所幫助！接下來，請跟著小編一起來學習吧！
1、CheckBox的聯動:
全選框、商鋪復選框以及商品復選框要做到滴水不漏的聯動，我的經驗是在監聽多選框時盡量采用click事件，避免使用checkChange事件（因為它總是能在你意想不到的地方調用），全選框可以通過商品價格來判斷，這個在代碼中也有體現。
2、數據的聯動和UI的聯動:
適配器的都是在外部類創建，而總價格等控件都是在調用適配器的地方，這個要做到聯動，最簡單的方式必然就是接口的回調，熟練使用可以節省很多代碼，提高編程效率。
再有一個比較容易出現問題的地方就在于，我們經常是首先更改數據，然后通知適配器刷新數據（notifyDataSetChanged()），這里要注意的一點就是在更新數據的時候，一定確保更新的傳遞到適配器中的數據集合，否則會發現這個更新適配器的方法是無效的。
其他相關問題代碼中均有體現，如果和我一樣是一個編程小白，仔細閱讀會有收獲滴。
代碼中沒有添加自己的資源，邏輯都有實現就是UI丑了一點
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="購物車" 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="全選" 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="刪除" android:layout_width="0dp" android:layout_height="wrap_content" /> <Button android:id="@+id/btn_buy" android:background="#f99" android:layout_weight="1" android:text="購買" android:layout_width="0dp" android:layout_height="wrap_content" /> </LinearLayout> </LinearLayout>
group_item:
注:這里圖了個簡單，商鋪名稱我是通過設置CheckBox的text來顯示的，另外取消焦點是為了不影響二級列表的點擊展開與收回子集列表
<?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;
}
//監聽加減事件回調接口
public interface onNumChangeListener{
void onNumChange(int groupID,int childID,boolean isAdd);
}
private onNumChangeListener mOnNumChangeListener;
public void setOnNumChangeListener(onNumChangeListener mOnNumChangeListener){
this.mOnNumChangeListener = mOnNumChangeListener;
}
//監聽多選框點擊事件回調接口。
public interface onCheckChangeListener{
void onGroupClick(int groupID);
void onChildClick(int groupID,int childID);
}
private onCheckChangeListener mOnCheckChangeListener;
public void setmOnCheckChangeListener(onCheckChangeListener mOnCheckChangeListener){
this.mOnCheckChangeListener = mOnCheckChangeListener;
}
//監聽價格需要更新回調接口
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;//右上角當前商品數量和底部當前已選中商品的價格
ExpandableListView expandableListView;//展示商品信息的二級列表
CheckBox checkAll;//左下角全選
Button btnDel,btnBuy;//底部刪除當前選中按鈕、購買按鈕
ArrayList<Group> groups = new ArrayList<>();//數據源集合
MyAdapter adapter;//自定義baseExpandable適配器
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();//控件初始化
initData();//數據初始化
changeGoodsNum();//初始化當前商品個數。
/**
* 自定義加減按鈕回調
* params: groupID:商鋪id childID:商品在當前商鋪的id isADD:非加即減
*/
adapter.setOnNumChangeListener(new MyAdapter.onNumChangeListener() {
@Override
public void onNumChange(int groupID, int childID, boolean isAdd) {
//獲得當前點擊商品的數量
int num = groups.get(groupID).getChildren().get(childID).getNum();
if (isAdd){//加
//在數據源中該商品數量自增1
groups.get(groupID).getChildren().get(childID).setNum(++num);
}else{//減
if (num == 1){//數量為1給出提示
Toast.makeText(MainActivity.this, "受不了了，不能再少了", Toast.LENGTH_SHORT).show();
}else{//在數據源中該商品數量自減1
groups.get(groupID).getChildren().get(childID).setNum(--num);
}
}
//更新UI
adapter.notifyDataSetChanged();
changeMoney();//更新價格顯示
}
});
//自定義商鋪和商品多選框點擊回調
adapter.setmOnCheckChangeListener(new MyAdapter.onCheckChangeListener() {
@Override
public void onGroupClick(int groupID) {//組點擊
//將數據源置反，以保持同步
groups.get(groupID).setCheck(!(groups.get(groupID).isCheck()));
//獲取當前選中狀態
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();
//更新價格顯示
changeMoney();
}
@Override
public void onChildClick(int groupID, int childID) {//商品點擊
//將數據源置反以保持同步
groups.get(groupID).getChildren().get(childID).setCheck(!(groups.get(groupID).getChildren().get(childID).isCheck()));
//判斷該條目及所有兄弟條目是否全部選中，以及時更新商鋪CheckBox
int flag = 0;
for (int i = 0 ; i < groups.get(groupID).getChildren().size() ; i++){
if (groups.get(groupID).getChildren().get(i).isCheck()){
flag++;
}
}
//如果該組下的選中數量與該集合長度相等，說明全部選中，更新組CheckBox
if (flag == groups.get(groupID).getChildren().size()){
groups.get(groupID).setCheck(true);
}else{
groups.get(groupID).setCheck(false);
}
//更新UI
adapter.notifyDataSetChanged();
//更新價格顯示
changeMoney();
}
});
//刪除按鈕點擊
btnDel.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
List<Group> toBeDeleteGroups = new ArrayList<Group>();// 待刪除的組元素列表
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>();// 待刪除的子元素列表
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();
//更新當前商品數量顯示
changeGoodsNum();
//更新當前價格顯示
changeMoney();
}
});
//購買按鈕，點擊提示當前選中金額
btnBuy.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String money = price.getText().toString();
Toast.makeText(MainActivity.this, "當前總金額:"+money, Toast.LENGTH_SHORT).show();
}
});
//全選按鈕，點擊更新視圖所有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();
//更新總價顯示
changeMoney();
}
});
//自定義回調更新總價
adapter.setmOnShouldChangeMoneyListener(new MyAdapter.onShouldChangeMoneyListener() {
@Override
public void onShouldChnageMoney() {
//更新總價顯示
changeMoney();
}
});
}
//初始化數據，設置適配器
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("店鋪"+i+"的商品:"+j,"",2,false,j+1));
}
groups.add(new Group("商鋪:"+i,false,children));
}
adapter = new MyAdapter(this,groups);
expandableListView.setAdapter(adapter);
for (int i = 0; i < groups.size(); i++)
{
expandableListView.expandGroup(i);// 初始化時，將ExpandableListView以展開的方式呈現
}
}
//獲得控件資源
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);
}
//當前購物車商品數量
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+"");
}
//更新總價
private void changeMoney(){
int money = 0;
int allMoney = 0;//獲得當前全部商品價格
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();
}
}
//當選中價格與全部價格相等，更新全選框
if (money == allMoney){
checkAll.setChecked(true);
}else{
checkAll.setChecked(false);
}
price.setText(money + "");
}
}效果圖:
到此，關于“Android如何實現簡單購物車”的學習就結束了，希望能夠解決大家的疑惑。理論與實踐的搭配能更好的幫助大家學習，快去試試吧！若想繼續學習更多相關知識，請繼續關注億速云網站，小編會繼續努力為大家帶來更多實用的文章！
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