本节要讲解的Adapter类控件是ExpandableListView,就是可折叠的列表,它是ListView的子类, 在ListView的基础上它把应用中的列表项分为几组,每组里又可包含多个列表项。至于样子, 类似于QQ联系人列表,他的用法与ListView非常相似,只是ExpandableListVivew显示的列表项 需由ExpandableAdapter提供。 下面我们来学习这个控件的基本使用! 官方API:ExpandableListView
- android:childDivider:指定各组内子类表项之间的分隔条,图片不会完全显示, 分离子列表项的是一条直线
- android:childIndicator:显示在子列表旁边的Drawable对象,可以是一个图像
- android:childIndicatorEnd:子列表项指示符的结束约束位置
- android:childIndicatorLeft:子列表项指示符的左边约束位置
- android:childIndicatorRight:子列表项指示符的右边约束位置
- android:childIndicatorStart:子列表项指示符的开始约束位置
- android:groupIndicator:显示在组列表旁边的Drawable对象,可以是一个图像
- android:indicatorEnd:组列表项指示器的结束约束位置
- android:indicatorLeft:组列表项指示器的左边约束位置
- android:indicatorRight:组列表项指示器的右边约束位置
- android:indicatorStart:组列表项指示器的开始约束位置
1. 扩展BaseExpandableListAdpter实现ExpandableAdapter。
2. 使用SimpleExpandableListAdpater将两个List集合包装成ExpandableAdapter
3. 使用simpleCursorTreeAdapter将Cursor中的数据包装成SimpleCuroTreeAdapter 本节示例使用的是第一个,扩展BaseExpandableListAdpter,我们需要重写该类中的相关方法, 下面我们通过一个代码示例来体验下!
我们来看下实现的效果图:
下面我们就来实现上图的这个效果:
核心是重写BaseExpandableListAdpter,其实和之前写的普通的BaseAdapter是类似的, 但是BaseExpandableListAdpter则分成了两部分:组和子列表,具体看代码你就知道了!
另外,有一点要注意的是,重写isChildSelectable()方法需要返回true,不然不会触发 子Item的点击事件!下面我们来写写:
首先是组和子列表的布局:
item_exlist_group.xml:
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="horizontal" android:padding="5dp"> <TextView android:id="@+id/tv_group_name" android:layout_width="match_parent" android:layout_height="56dp" android:gravity="center_vertical" android:paddingLeft="30dp" android:text="AP" android:textStyle="bold" android:textSize="20sp" /> </LinearLayout>
item_exlist_item.xml:
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="horizontal" android:padding="5dp" android:background="#6BBA79"> <ImageView android:id="@+id/img_icon" android:layout_width="48dp" android:layout_height="48dp" android:src="@mipmap/iv_lol_icon1" android:focusable="false"/> <TextView android:id="@+id/tv_name" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginLeft="15dp" android:layout_marginTop="15dp" android:focusable="false" android:text="提莫" android:textSize="18sp" /> </LinearLayout>
然后是自定义的Adapter类:
MyBaseExpandableListAdapter.java:
/** * Created by Jay on 2015/9/25 0025. */ public class MyBaseExpandableListAdapter extends BaseExpandableListAdapter { private ArrayList<Group> gData; private ArrayList<ArrayList<Item>> iData; private Context mContext; public MyBaseExpandableListAdapter(ArrayList<Group> gData,ArrayList<ArrayList<Item>> iData, Context mContext) { this.gData = gData; this.iData = iData; this.mContext = mContext; } @Override public int getGroupCount() { return gData.size(); } @Override public int getChildrenCount(int groupPosition) { return iData.get(groupPosition).size(); } @Override public Group getGroup(int groupPosition) { return gData.get(groupPosition); } @Override public Item getChild(int groupPosition, int childPosition) { return iData.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; } //取得用于显示给定分组的视图. 这个方法仅返回分组的视图对象 @Override public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) { ViewHolderGroup groupHolder; if(convertView == null){ convertView = LayoutInflater.from(mContext).inflate( R.layout.item_exlist_group, parent, false); groupHolder = new ViewHolderGroup(); groupHolder.tv_group_name = (TextView) convertView.findViewById(R.id.tv_group_name); convertView.setTag(groupHolder); }else{ groupHolder = (ViewHolderGroup) convertView.getTag(); } groupHolder.tv_group_name.setText(gData.get(groupPosition).getgName()); return convertView; } //取得显示给定分组给定子位置的数据用的视图 @Override public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) { ViewHolderItem itemHolder; if(convertView == null){ convertView = LayoutInflater.from(mContext).inflate( R.layout.item_exlist_item, parent, false); itemHolder = new ViewHolderItem(); itemHolder.img_icon = (ImageView) convertView.findViewById(R.id.img_icon); itemHolder.tv_name = (TextView) convertView.findViewById(R.id.tv_name); convertView.setTag(itemHolder); }else{ itemHolder = (ViewHolderItem) convertView.getTag(); } itemHolder.img_icon.setImageResource(iData.get(groupPosition).get(childPosition).getiId()); itemHolder.tv_name.setText(iData.get(groupPosition).get(childPosition).getiName()); return convertView; } //设置子列表是否可选中 @Override public boolean isChildSelectable(int groupPosition, int childPosition) { return true; } private static class ViewHolderGroup{ private TextView tv_group_name; } private static class ViewHolderItem{ private ImageView img_icon; private TextView tv_name; } }
PS:存储子列表的数据不一定要用ArrayList<ArrayList>这种,根据自己的需求 定义~
最后是MainActivity的布局以及Java代码:
布局文件:activity_main.xml:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:padding="5dp" tools:context=".MainActivity"> <ExpandableListView android:id="@+id/exlist_lol" android:layout_width="match_parent" android:layout_height="match_parent" android:childDivider="#E02D2F"/> </RelativeLayout>
MainActivity.java:
public class MainActivity extends AppCompatActivity { private ArrayList<Group> gData = null; private ArrayList<ArrayList<Item>> iData = null; private ArrayList<Item> lData = null; private Context mContext; private ExpandableListView exlist_lol; private MyBaseExpandableListAdapter myAdapter = null; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mContext = MainActivity.this; exlist_lol = (ExpandableListView) findViewById(R.id.exlist_lol); //数据准备 gData = new ArrayList<Group>(); iData = new ArrayList<ArrayList<Item>>(); gData.add(new Group("AD")); gData.add(new Group("AP")); gData.add(new Group("TANK")); lData = new ArrayList<Item>(); //AD组 lData.add(new Item(R.mipmap.iv_lol_icon3,"剑圣")); lData.add(new Item(R.mipmap.iv_lol_icon4,"德莱文")); lData.add(new Item(R.mipmap.iv_lol_icon13,"男枪")); lData.add(new Item(R.mipmap.iv_lol_icon14,"韦鲁斯")); iData.add(lData); //AP组 lData = new ArrayList<Item>(); lData.add(new Item(R.mipmap.iv_lol_icon1, "提莫")); lData.add(new Item(R.mipmap.iv_lol_icon7, "安妮")); lData.add(new Item(R.mipmap.iv_lol_icon8, "天使")); lData.add(new Item(R.mipmap.iv_lol_icon9, "泽拉斯")); lData.add(new Item(R.mipmap.iv_lol_icon11, "狐狸")); iData.add(lData); //TANK组 lData = new ArrayList<Item>(); lData.add(new Item(R.mipmap.iv_lol_icon2, "诺手")); lData.add(new Item(R.mipmap.iv_lol_icon5, "德邦")); lData.add(new Item(R.mipmap.iv_lol_icon6, "奥拉夫")); lData.add(new Item(R.mipmap.iv_lol_icon10, "龙女")); lData.add(new Item(R.mipmap.iv_lol_icon12, "狗熊")); iData.add(lData); myAdapter = new MyBaseExpandableListAdapter(gData,iData,mContext); exlist_lol.setAdapter(myAdapter); //为列表设置点击事件 exlist_lol.setOnChildClickListener(new ExpandableListView.OnChildClickListener() { @Override public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) { Toast.makeText(mContext, "你点击了:" + iData.get(groupPosition).get(childPosition).getiName(), Toast.LENGTH_SHORT).show(); return true; } }); } }
好的,本节给大家介绍了ExpandableListView的基本使用,嘿嘿,有点意思~ 这里只是一个示例,其他的根据自己的需求自行扩展~谢谢