Android 购物车（精仿）可删可全选与反选

展示效果

主Activity中的方法

public class MainActivity extends Activity implements ShopcartExpandableListViewAdapter.CheckInterface, ShopcartExpandableListViewAdapter.ModifyCountInterface, OnClickListener
{
private ExpandableListView exListView;
private CheckBox cb_check_all;
private TextView tv_total_price;
private TextView tv_delete;
private TextView tv_go_to_pay;
private Context context;

private double totalPrice = 0.00;// 购买的商品总价
private int totalCount = 0;// 购买的商品总数量

private ShopcartExpandableListViewAdapter selva;
private List<GroupInfo> groups = new ArrayList<GroupInfo>();// 组元素数据列表
private Map<String, List<ProductInfo>> children = new HashMap<String, List<ProductInfo>>();// 子元素数据列表

@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);

initView();
initEvents();
}

private void initView()
{
context = this;
virtualData();
exListView = (ExpandableListView) findViewById(R.id.exListView);
cb_check_all = (CheckBox) findViewById(R.id.all_chekbox);
tv_total_price = (TextView) findViewById(R.id.tv_total_price);
tv_delete = (TextView) findViewById(R.id.tv_delete);
tv_go_to_pay = (TextView) findViewById(R.id.tv_go_to_pay);
}

private void initEvents()
{
selva = new ShopcartExpandableListViewAdapter(groups, children, this);
selva.setCheckInterface(this);// 关键步骤1,设置复选框接口
selva.setModifyCountInterface(this);// 关键步骤2,设置数量增减接口
exListView.setAdapter(selva);

for (int i = 0; i < selva.getGroupCount(); i++)
{
exListView.expandGroup(i);// 关键步骤3,初始化时，将ExpandableListView以展开的方式呈现
}

cb_check_all.setOnClickListener(this);
tv_delete.setOnClickListener(this);
tv_go_to_pay.setOnClickListener(this);
}

/**
* 模拟数据<br>
* 遵循适配器的数据列表填充原则，组元素被放在一个List中，对应的组元素下辖的子元素被放在Map中，<br>
* 其键是组元素的Id(通常是一个唯一指定组元素身份的值)
*/
private void virtualData()
{

for (int i = 0; i < 6; i++)
{

groups.add(new GroupInfo(i + "", "第八号当铺" + (i + 1) + "号店"));

List<ProductInfo> products = new ArrayList<ProductInfo>();
for (int j = 0; j <= i; j++)
{

products.add(new ProductInfo(j + "", "商品", "", groups.get(i).getName() + "的第" + (j + 1) + "个商品", 120.00 + i * j, 1));
}
children.put(groups.get(i).getId(), products);// 将组元素的一个唯一值，这里取Id，作为子元素List的Key
}
}

@Override
public void onClick(View v)
{
AlertDialog alert;
switch (v.getId())
{
case R.id.all_chekbox:
doCheckAll();
break;
case R.id.tv_go_to_pay:
if (totalCount == 0)
{
Toast.makeText(context, "请选择要支付的商品", Toast.LENGTH_LONG).show();
return;
}
alert = new AlertDialog.Builder(context).create();
alert.setTitle("操作提示");
alert.setMessage("总计:\n" + totalCount + "种商品\n" + totalPrice + "元");
alert.setButton(DialogInterface.BUTTON_NEGATIVE, "取消", new DialogInterface.OnClickListener()
{
@Override
public void onClick(DialogInterface dialog, int which)
{
return;
}
});
alert.setButton(DialogInterface.BUTTON_POSITIVE, "确定", new DialogInterface.OnClickListener()
{
@Override
public void onClick(DialogInterface dialog, int which)
{
return;
}
});
alert.show();
break;
case R.id.tv_delete:
if (totalCount == 0)
{
Toast.makeText(context, "请选择要移除的商品", Toast.LENGTH_LONG).show();
return;
}
alert = new AlertDialog.Builder(context).create();
alert.setTitle("操作提示");
alert.setMessage("您确定要将这些商品从购物车中移除吗？");
alert.setButton(DialogInterface.BUTTON_NEGATIVE, "取消", new DialogInterface.OnClickListener()
{
@Override
public void onClick(DialogInterface dialog, int which)
{

cca9
return;
}
});
alert.setButton(DialogInterface.BUTTON_POSITIVE, "确定", new DialogInterface.OnClickListener()
{
@Override
public void onClick(DialogInterface dialog, int which)
{
doDelete();
}
});
alert.show();
break;
}
}

/**
* 删除操作<br>
* 1.不要边遍历边删除，容易出现数组越界的情况<br>
* 2.现将要删除的对象放进相应的列表容器中，待遍历完后，以removeAll的方式进行删除
*/
protected void doDelete()
{
List<GroupInfo> toBeDeleteGroups = new ArrayList<GroupInfo>();// 待删除的组元素列表
for (int i = 0; i < groups.size(); i++)
{
GroupInfo group = groups.get(i);
if (group.isChoosed())
{

toBeDeleteGroups.add(group);
}
List<ProductInfo> toBeDeleteProducts = new ArrayList<ProductInfo>();// 待删除的子元素列表
List<ProductInfo> childs = children.get(group.getId());
for (int j = 0; j < childs.size(); j++)
{
if (childs.get(j).isChoosed())
{
toBeDeleteProducts.add(childs.get(j));
}
}
childs.removeAll(toBeDeleteProducts);

}

groups.removeAll(toBeDeleteGroups);

selva.notifyDataSetChanged();
calculate();
}

@Override
public void doIncrease(int groupPosition, int childPosition, View showCountView, boolean isChecked)
{

ProductInfo product = (ProductInfo) selva.getChild(groupPosition, childPosition);
int currentCount = product.getCount();
currentCount++;
product.setCount(currentCount);
((TextView) showCountView).setText(currentCount + "");

selva.notifyDataSetChanged();
calculate();
}

@Override
public void doDecrease(int groupPosition, int childPosition, View showCountView, boolean isChecked)
{

ProductInfo product = (ProductInfo) selva.getChild(groupPosition, childPosition);
int currentCount = product.getCount();
if (currentCount == 1)
return;
currentCount--;

product.setCount(currentCount);
((TextView) showCountView).setText(currentCount + "");

selva.notifyDataSetChanged();
calculate();
}

@Override
public void checkGroup(int groupPosition, boolean isChecked)
{
GroupInfo group = groups.get(groupPosition);
List<ProductInfo> childs = children.get(group.getId());
for (int i = 0; i < childs.size(); i++)
{
childs.get(i).setChoosed(isChecked);
}
if (isAllCheck())
cb_check_all.setChecked(true);
else
cb_check_all.setChecked(false);
selva.notifyDataSetChanged();
calculate();
}

@Override
public void checkChild(int groupPosition, int childPosiTion, boolean isChecked)
{
boolean allChildSameState = true;// 判断改组下面的所有子元素是否是同一种状态
GroupInfo group = groups.get(groupPosition);
List<ProductInfo> childs = children.get(group.getId());
for (int i = 0; i < childs.size(); i++)
{
if (childs.get(i).isChoosed() != isChecked)
{
allChildSameState = false;
break;
}
}
if (allChildSameState)
{
group.setChoosed(isChecked);// 如果所有子元素状态相同，那么对应的组元素被设为这种统一状态
} else
{
group.setChoosed(false);// 否则，组元素一律设置为未选中状态
}

if (isAllCheck())
cb_check_all.setChecked(true);
else
cb_check_all.setChecked(false);
selva.notifyDataSetChanged();
calculate();
}

private boolean isAllCheck()
{

for (GroupInfo group : groups)
{
if (!group.isChoosed())
return false;

}

return true;
}

/** 全选与反选 */
private void doCheckAll()
{
for (int i = 0; i < groups.size(); i++)
{
groups.get(i).setChoosed(cb_check_all.isChecked());
GroupInfo group = groups.get(i);
List<ProductInfo> childs = children.get(group.getId());
for (int j = 0; j < childs.size(); j++)
{
childs.get(j).setChoosed(cb_check_all.isChecked());
}
}
selva.notifyDataSetChanged();
}

/**
* 统计操作<br>
* 1.先清空全局计数器<br>
* 2.遍历所有子元素，只要是被选中状态的，就进行相关的计算操作<br>
* 3.给底部的textView进行数据填充
*/
private void calculate()
{
totalCount = 0;
totalPrice = 0.00;
for (int i = 0; i < groups.size(); i++)
{
GroupInfo group = groups.get(i);
List<ProductInfo> childs = children.get(group.getId());
for (int j = 0; j < childs.size(); j++)
{
ProductInfo product = childs.get(j);
if (product.isChoosed())
{
totalCount++;
totalPrice += product.getPrice() * product.getCount();
}
}
}
tv_total_price.setText("￥" + totalPrice);
tv_go_to_pay.setText("去支付(" + totalCount + ")");
}
}

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