Android普通购物车 Android制作简单的普通购物车

时间:2021-03-22 baidu_17508977 人气:0

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1.最新项目新增了类似购物车功能，如下图所示：

当时刚看到此页面的时候，第一反应是利用 ListView嵌套Listview,经过一番操作最终也实现了此功能。当时也没有考虑性能问题，只考虑能写出来。后来嵌套数据，当数据量较大时，滑动Listview可以明显感觉到卡顿，这对用户来说是很难忍受的，所以才有了找到替代方案的想法，看到网上主流的是用ExpandableListView来实现此功能，所以我也用此方案来写一下。

2.成型后的Demo，如下图所示：

3.思路：
1）.选用ExpandableListView作为控件
2）.给每个数据源添加一个选中标志，isChecked,根据ischecked，控制checkbox的状态;

ExpandableListView相关普及

#1.首先看下ExpandableListView的adapter，与普通的ListView adapter不同

public class MyExpandAdapter extends BaseExpandableListAdapter {
//红色部分的数据源
List<OrderDetailsEntity> group_head = new ArrayList();
//内层部分数据源
List<List<ProductDetails>> child = new ArrayList();
Context context;
LayoutInflater inflater;

public MyExpandAdapter(Context content) {
 // 初始化组、子列表项
 group_head = new ArrayList<OrderDetailsEntity>();
 child = new ArrayList<List<ProductDetails>>();
 inflater = LayoutInflater.from(context);
}

public MyExpandAdapter(Context context, List<OrderDetailsEntity> group_head, List<List<ProductDetails>> child) {
 this.context = context;
 // 初始化组、子列表项
 this.group_head = group_head;
 this.child = child;
 inflater = LayoutInflater.from(context);
}
/****************************跟普通adapter一样******************************/
@Override
public int getGroupCount() {
 return this.group_head.size();
}

@Override
public int getChildrenCount(int position) {
 if (position < 0 || position >= this.child.size())
 return 0;
 return child.get(position).size();
}

@Override
public OrderDetailsEntity getGroup(int groupPosition) {
 return group_head.get(groupPosition);
}

@Override
public ProductDetails getChild(int groupPosition, int childPosition) {

 return child.get(groupPosition).get(childPosition);
}

@Override
public long getGroupId(int groupPosition) {
 return groupPosition;
}

@Override
public long getChildId(int groupPosition, int childPosition) {
 return childPosition;
}
/**************************************************************************/
@Override
public boolean hasStableIds() {
//分组和子选项是否持有稳定的ID, 就是说底层数据的改变会不会影响到它们
 return true;
}

private boolean isSelectAll(OrderDetailsEntity entity) {
 int count = 0;
 for (ProductDetails p : entity.getProductDetails()) {
 if (p.isChecked()) {
 count++;
 }
 }

 return entity.getProductDetails().size() == count;
}

/*************************与普通adapter的getView方法一样**********************/
@Override
public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
 ViewHolderGroup group;
 if (convertView == null) {
 convertView = inflater.inflate(R.layout.item, parent, false);
 group = new ViewHolderGroup();
 group.cb_all = (CheckBox) convertView.findViewById(R.id.cb_checkAll);
 group.tv_name = (TextView) convertView.findViewById(R.id.tv_name);
 convertView.setTag(group);
 } else {
 group = (ViewHolderGroup) convertView.getTag();
 }
 group.tv_name.setText(
 group_head.get(groupPosition).getMemberId() + "," + group_head.get(groupPosition).getShopName());
 group.cb_all.setChecked(isSelectAll(getGroup(groupPosition)));
 return convertView;
}

@Override
public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView,
 ViewGroup parent) {
 ViewHolderChild childV;
 if (convertView == null) {
 convertView = inflater.inflate(R.layout.item_inner, parent, false);
 childV = new ViewHolderChild();
 childV.cb = (CheckBox) convertView.findViewById(R.id.cb_check);
 childV.iv = (ImageView) convertView.findViewById(R.id.iv_img);
 childV.name = (TextView) convertView.findViewById(R.id.name);
 convertView.setTag(childV);
 } else {
 childV = (ViewHolderChild) convertView.getTag();
 }

 childV.name.setText(getChild(groupPosition, childPosition).getProductName());
 childV.cb.setChecked(getChild(groupPosition, childPosition).isChecked());

 return convertView;
}

/****************************************************************************/

@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
 //// 指定位置的子视图是否可选择。
 // 调用Activity里的ChildSelect方法
 // Toast.makeText(context, "gp="+groupPosition+",cp="+childPosition,
 // Toast.LENGTH_LONG).show();
 return true;
}

static class ViewHolderGroup {
 CheckBox cb_all;
 TextView tv_name;
}

static class ViewHolderChild {
 CheckBox cb;
 ImageView iv;
 TextView name;
}
}

#2.ExpandableListView 展开

for (int i = 0; i < adapter.getGroupCount(); i++) { 
sp_date_list.expandGroup(i); 
}

3）.ExpandableListView 去掉默认图标

sp_date_list.setGroupIndicator(null);

4）.ExpandableListView itemClick事件处理

1. setOnChildClickListener
2. setOnGroupClickListener
3. setOnGroupCollapseListener
4. setOnGroupExpandListener

通过方法名我们就能知道各自的用途，它们分别设置单击子选项、单击分组项、分组合并、分组展开的监听器。

// 设置分组项的点击监听事件
expandableListView.setOnGroupClickListener(new ExpandableListView.OnGroupClickListener() {
@Override
public boolean onGroupClick(ExpandableListView expandableListView, View view, int i, long l) {
 Toast.makeText(getApplicationContext(), groupStrings[i], Toast.LENGTH_SHORT).show();
 //如果处理事件，return true,默认return false
 return false;
}
// 设置子选项点击监听事件
expandableListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
@Override
public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
 Toast.makeText(getApplicationContext(), childStrings[groupPosition][childPosition], Toast.LENGTHshow();
 return true;
}
});

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