安卓二级列表的适配器 带优化的 解决二级列表里添加了自定义view以后不能点击展开的问题

在自定义的item项layout中加入
dandroid:descendantFocusability="blocksDescendants"
开发中很常见的一个问题，项目中的listview不仅仅是简单的文字，常常需要自己定义listview，自己的Adapter去继承BaseAdapter，在adapter中按照需求进行编写，问题就出现了，可能会发生点击每一个item的时候没有反应，无法获取的焦点。原因多半是由于在你自己定义的Item中存在诸如ImageButton，Button，CheckBox等子控件(也可以说是Button或者Checkable的子类控件)，此时这些子控件会将焦点获取到，所以常常当点击item时变化的是子控件，item本身的点击没有响应。
    这时候就可以使用descendantFocusability来解决啦，API描述如下：
android:descendantFocusability
Defines the relationship between the ViewGroup and its descendants when looking for a View to take focus.
Must be one of the following constant values.
 
该属性是当一个为view获取焦点时，定义viewGroup和其子控件两者之间的关系。
属性的值有三种：
        beforeDescendants：viewgroup会优先其子类控件而获取到焦点
        afterDescendants：viewgroup只有当其子类控件不需要获取焦点时才获取焦点
        blocksDescendants：viewgroup会覆盖子类控件而直接获得焦点
 
通常我们用到的是第三种，即在Item布局的根布局加上android:descendantFocusability=”blocksDescendants”的属性就好了
下面是适配器:适用于安卓二级列表import android.content.Context;import android.view.View;import android.view.ViewGroup;import android.widget.BaseExpandableListAdapter;import android.widget.CheckBox;import android.widget.TextView;import com.bwei.erjigou.Bean.Goodsbean;import com.bwei.erjigou.Bean.Groupbean;import com.bwei.erjigou.R;import java.util.List;/** * Created by 31962 on 2017/10/24. */public class MyElvAdapter extends BaseExpandableListAdapter {    private List<Groupbean> grouplist;    private List<List<Goodsbean>> childlist;    private Context context;    public MyElvAdapter(List<Groupbean> grouplist, List<List<Goodsbean>> childlist, Context context) {        this.grouplist = grouplist;        this.childlist = childlist;        this.context = context;    }    @Override    public int getGroupCount() {        return grouplist.size();    }    @Override    public int getChildrenCount(int groupPosition) {        return childlist.get(groupPosition).size();    }    @Override    public Object getGroup(int groupPosition) {        return grouplist.get(groupPosition);    }    @Override    public Object getChild(int groupPosition, int childPosition) {        return childlist.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() {        return false;    }    @Override    public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {        GroupViewholder groupViewholder ;        if(convertView == null){            groupViewholder = new GroupViewholder();            convertView =  View.inflate(context, R.layout.groupitem, null);           groupViewholder.cb_group =  convertView.findViewById(R.id.cb_group);            groupViewholder.tv_group = convertView.findViewById(R.id.tv_group);            convertView.setTag(groupViewholder);        }else{            groupViewholder = (GroupViewholder) convertView.getTag();        }        groupViewholder.cb_group.setChecked(grouplist.get(groupPosition).ischecked);        groupViewholder.tv_group.setText(grouplist.get(groupPosition).groupname);        return convertView;    }    @Override    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {        ChildViewholder childviewholder ;        if(convertView == null){            childviewholder = new ChildViewholder();            convertView = View.inflate(context,R.layout.childitem,null);            childviewholder.cb_child = convertView.findViewById(R.id.cb_child);            childviewholder.tv_child = convertView.findViewById(R.id.tv_child);            convertView.setTag(childviewholder);        }else {            childviewholder = (ChildViewholder) convertView.getTag();        }        childviewholder.cb_child.setChecked(childlist.get(groupPosition).get(childPosition).ischecked);        childviewholder.tv_child.setText(childlist.get(groupPosition).get(childPosition).goodsname);        return convertView;    }    @Override    public boolean isChildSelectable(int groupPosition, int childPosition) {        return true;    }     class GroupViewholder{        CheckBox cb_group;        TextView tv_group;    }     class ChildViewholder{        CheckBox cb_child;        TextView tv_child;    }}