編輯：關於Android編程
最近寫了一個商城APP中常用功能“購物車”
購物車效果圖如下：
![購物車效果圖](https://www.android5.online/Android/UploadFiles_5356/201702/2017022216391559.png "\")
購物車功能需求如下：
![購物車要求](https://www.android5.online/Android/UploadFiles_5356/201702/2017022216391676.png "\")
下面是購物車主activity“MainActivity”代碼：
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import retrofit2.Response;
import shop.hsy.com.shopcar.adapter.ShopAdapter;
import shop.hsy.com.shopcar.entity.ResultModel;
import shop.hsy.com.shopcar.entity.Shopping;
import shop.hsy.com.shopcar.net.ShopCarNet;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private ListView shop_list;
private ShopAdapter shopAdapter;
private TextView prices;
private CheckBox all_checks;
private TextView settlement;
private TextView delete_text;
private Response>> modelResponse;//接口請求回來的數據
private List shoppingList = new ArrayList<>();//重新整合後的數據
private ProgressDialog progressDialog;
private int a=0;//此字段非常重要，用來解決全選與單選沖突
private int b=1;//此字段非常重要，用來解決字段a與全選沖突
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
progressDialog = new ProgressDialog(MainActivity.this);
progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
progressDialog.setMessage("······");
initview();
}
private void initview(){
shop_list = (ListView) findViewById(R.id.shop_list);
shopAdapter = new ShopAdapter(MainActivity.this);
shop_list.setAdapter(shopAdapter);
all_checks = (CheckBox) findViewById(R.id.all_checks);//全選
prices = (TextView) findViewById(R.id.prices);//價格
settlement = (TextView) findViewById(R.id.settlement);//結算
delete_text = (TextView) findViewById(R.id.delete_text);//刪除
settlement.setOnClickListener(this);
delete_text.setOnClickListener(this);
getShopData(22+"");
AllChecks();
}
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.settlement: //結算
Settlement();
break;
case R.id.delete_text: //刪除
AllDelete();
break;
}
}
/**
* 數據接口請求
* @param mid
*/
private void getShopData(final String mid){
new Thread(new Runnable() {
@Override
public void run() {
try {
modelResponse = ShopCarNet.getShop(mid).execute();
Message message = mhandler.obtainMessage();
message.what = 0;
message.sendToTarget();
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();
}
private Handler mhandler = new Handler(){
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
switch (msg.what){
case 0:
if(modelResponse!=null){
if(modelResponse.body()!=null){
if(modelResponse.body().getData()!=null
&&modelResponse.body().getData().size()>0){
for (Shopping shop:modelResponse.body().getData()) {
shop.setChecks(false);//給商品添加為選中狀態
shoppingList.add(shop);
}
shopAdapter.addItem(shoppingList);
shopAdapter.notifyDataSetChanged();
}
}
}else{
Log.e("mainactivity","沒有數據");
}
break;
}
}
};
/**
* 全選check監聽
*/
public void AllChecks(){
all_checks.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
progressDialog.show();
if(b==0){
a=0;b=1;
}
if(a==0) {//解決單選與全選沖突
if (isChecked) {//true：全選被選中，false：全選取消
double AllPrice = 0;
for (Shopping shop : shoppingList) {
shop.setChecks(true);//改變商品選中狀態
AllPrice = AllPrice + Double.valueOf(shop.p_price) * shop.p_number;//計算商品總價
}
prices.setText("￥" + AllPrice);//顯示總價
} else {
b=0;
for (Shopping shop : shoppingList) {
shop.setChecks(false);//改變商品未選中狀態
}
prices.setText("￥0.0");//價格改為0
}
shopAdapter.clear();
shopAdapter.addItem(shoppingList);//添加改編後的數據到list的Adapter
shopAdapter.notifyDataSetChanged();//刷新列表
}
a=0;
if (progressDialog != null) progressDialog.cancel();
}
});
}
/**
* 選中，加減方法
* @param checks 是否被選中
* @param count 被選中的商品id
* @param number 被選中商品的數量
*/
public void UpView(boolean checks, int count,int number){
progressDialog.show();
double AllPrice = 0;
int size = 0 ;//用來計數，判斷數據是否被全部選中
for (Shopping shop:shoppingList) {
if(shop.p_id == count){//查找被選中商品id
shop.setChecks(checks);//改變商品集合shoppingList中的選中狀態
shop.p_number = number;//同時修改商品數量
}
if(shop.isChecks()){//判斷商品是否被選中，如被選中計算價格
size++;
AllPrice =AllPrice + Double.valueOf(shop.p_price) * shop.p_number;//得到被選中商品的總價格
}
}
shopAdapter.clear();
shopAdapter.addItem(shoppingList);
shopAdapter.notifyDataSetChanged();
prices.setText("￥"+AllPrice);
if(size == shoppingList.size()){
all_checks.setChecked(true);//是全部被選中，改變全選check狀態為選中
}else{
a = 1;//a=1表示all_checks監聽中方法不執行
if(!all_checks.isChecked()) a=0;//all_checks未被選中給a賦值0讓all_checks的監聽中的方法繼續執行
all_checks.setChecked(false);//不是，繼續維持未選中狀態
}
if (progressDialog != null) progressDialog.cancel();
}
/**
* 結算方法
*/
public void Settlement(){
List settlement_list = new ArrayList<>();
final List new_list = new ArrayList<>();
for (Shopping shop:shoppingList) {
if(shop.isChecks()){
settlement_list.add(shop.p_id);//取出被選中商品id加入新的list准備掉接口完成結算
}else{
new_list.add(shop);//剩余商品形成新的購物車列表等待顯示
}
}
if(settlement_list.size()==0){
Toast.makeText(MainActivity.this,"請選中至少一個商品後在結算",Toast.LENGTH_SHORT).show();
return;
}
AlertDialog.Builder dialog = new AlertDialog.Builder(MainActivity.this);
dialog.setTitle("提示").setMessage("總共"+settlement_list.size()+"個商品，共"+prices.getText().toString()+"元，是否要結算？");
dialog.setPositiveButton("確定", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
//在這裡調結算接口把delete_list傳給後台
shoppingList = new_list;
shopAdapter.clear();
shopAdapter.addItem(shoppingList);
shopAdapter.notifyDataSetChanged();
prices.setText("￥0.0");
dialog.cancel();
}
}).setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
}).create().show();
}
/**
* 刪除方法
* 該方法類似結算方法
*/
public void AllDelete(){
List delete_list = new ArrayList<>();
final List new_list = new ArrayList<>();
for (Shopping shop:shoppingList) {
if(shop.isChecks()){
delete_list.add(shop.p_id);
}else{
new_list.add(shop);
}
}
if(delete_list.size()==0){
Toast.makeText(MainActivity.this,"請選中至少一個商品後在刪除",Toast.LENGTH_SHORT).show();
return;
}
AlertDialog.Builder dialog = new AlertDialog.Builder(MainActivity.this);
dialog.setTitle("提示").setMessage("確定要刪除這"+delete_list.size()+"個商品?");
dialog.setPositiveButton("確定", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
//在這裡調刪除接口把delete_list傳給後台
shoppingList = new_list;
shopAdapter.clear();
shopAdapter.addItem(shoppingList);
shopAdapter.notifyDataSetChanged();
prices.setText("￥0.0");
dialog.cancel();
}
}).setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
}).create().show();
}
}
MainActivity的布局文件很簡單：
購物車Adapter代碼“ShopAdapter”，由於我繼承一個BaseAtapter，所以這個Adapter我只需要處理getView方法：
import android.content.Context;
import android.graphics.Paint;
import android.text.TextUtils;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import com.nostra13.universalimageloader.core.ImageLoader;
import shop.hsy.com.shopcar.MainActivity;
import shop.hsy.com.shopcar.MyApplication;
import shop.hsy.com.shopcar.R;
import shop.hsy.com.shopcar.entity.Shopping;
/**
* Created by hsy on 2016/11/10.
*/
public class ShopAdapter extends BaseAdapter {
private LayoutInflater inflater;
private Context context;
private MainActivity mainActivity;
public ShopAdapter(Context context) {
this.context = context;
mainActivity = (MainActivity)context;
inflater = LayoutInflater.from(context);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
if (convertView == null) {
holder = new ViewHolder();
convertView = inflater.inflate(R.layout.shop_item, parent, false);
holder.checks = (CheckBox) convertView.findViewById(R.id.checks);//選擇框
holder.p_img1 = (ImageView) convertView.findViewById(R.id.p_img1);//商品縮略圖
holder.p_name = (TextView) convertView.findViewById(R.id.p_name);//名稱
holder.p_price = (TextView) convertView.findViewById(R.id.p_price);//價格
holder.p_mprice = (TextView) convertView.findViewById(R.id.p_mprice);//過時價格
holder.p_discount = (TextView) convertView.findViewById(R.id.p_discount);//折扣
holder.p_news = (TextView) convertView.findViewById(R.id.p_news);//成色
holder.p_stock = (TextView) convertView.findViewById(R.id.p_stock);//庫存
holder.p_number = (TextView) convertView.findViewById(R.id.p_number);//數量
holder.minus = (ImageView) convertView.findViewById(R.id.minus);//減
holder.add = (ImageView) convertView.findViewById(R.id.add);//加
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
final Shopping shopping = (Shopping) getItem(position);
if (!TextUtils.isEmpty(shopping.p_img1)) {
ImageLoader.getInstance().displayImage(shopping.p_img1, holder.p_img1, MyApplication.option);
}else {
holder.p_img1.setImageResource(R.mipmap.ic_launcher);
}
holder.p_name.setText(shopping.p_name);
holder.p_price.setText(shopping.p_price);
holder.p_mprice.setText(shopping.p_mprice);
holder.p_discount.setText(shopping.p_discount);
holder.p_news.setText(shopping.p_news);
holder.p_number.setText(shopping.p_number+"");
holder.p_stock.setText(shopping.p_stock);
holder.checks.setChecked(shopping.isChecks());
holder.p_mprice.getPaint().setFlags(Paint.STRIKE_THRU_TEXT_FLAG | Paint.ANTI_ALIAS_FLAG);
//全選監聽
holder.checks.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
mainActivity.UpView(isChecked, shopping.p_id, shopping.p_number);
}
});
//數量減
holder.minus.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int minus = 0;
if(shopping.p_number>1) {
minus = shopping.p_number-1;
mainActivity.UpView(shopping.isChecks(), shopping.p_id, minus);
}else{
Toast.makeText(context,"數量不能再少了",Toast.LENGTH_SHORT).show();
}
}
});
//數量加
holder.add.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mainActivity.UpView(shopping.isChecks(),shopping.p_id,(shopping.p_number+1));
}
});
return convertView;
}
private class ViewHolder {
private CheckBox checks;
private ImageView p_img1;
private TextView p_name;
private TextView p_price;
private TextView p_mprice;
private TextView p_discount;
private TextView p_news;
private TextView p_stock;
private TextView p_number;
private ImageView minus;
private ImageView add;
}
}
Adapter布局文件：
至此，購物車功能就實現了，這裡最主要的就是MainActivity中的UpView方法，其次就是CheckBox的監聽（setOnCheckedChangeListener）； 注意 ：在MainActivity中我用了a和b兩個字段來解決Adapter中的CheckBox監聽和Activity中的CheckBox監聽沖突問題。
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