UI控件之七

ExpandableListView（可折叠列表）

1 常用属性

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
childIndicator：显示在子列表旁边的Drawable对象，可以是一个图像
childIndicatorEnd：子列表项指示符的结束约束位置
childIndicatorLeft：子列表项指示符的左边约束位置
childIndicatorRight：子列表项指示符的右边约束位置
childIndicatorStart：子列表项指示符的开始约束位置
groupIndicator：显示在组列表旁边的Drawable对象，可以是一个图像
indicatorEnd：组列表项指示器的结束约束位置
indicatorLeft：组列表项指示器的左边约束位置
indicatorRight：组列表项指示器的右边约束位置
indicatorStart：组列表项指示器的开始约束位置

2 说明

实现ExpandableAdapter的三种方式：

扩展BaseExpandableListAdpter实现ExpandableAdapter。
使用SimpleExpandableListAdpater将两个List集合包装成ExpandableAdapter
使用simpleCursorTreeAdapter将Cursor中的数据包装成SimpleCuroTreeAdapter

3 实例

定义组布局item_group_xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">

    <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="分组"
            android:textStyle="bold"
            android:textSize="20sp" />

</LinearLayout>

定义列表项布局item_child.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="@drawable/logo"
            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="图标"
            android:textSize="18sp" />

</LinearLayout>

定义实体类Icon.java

public class Icon {
    private int iId;
    private String iName;

    public Icon() {
    }

    public Icon(int iId, String iName) {
        this.iId = iId;
        this.iName = iName;
    }

    public int getiId() {
        return iId;
    }

    public String getiName() {
        return iName;
    }

    public void setiId(int iId) {
        this.iId = iId;
    }

    public void setiName(String iName) {
        this.iName = iName;
    }
}

自定义BaseExpandableListAdapter

public class MyBaseExpandableListAdapter extends BaseExpandableListAdapter {

    private ArrayList<String> gData;
    private ArrayList<ArrayList<Icon>> iData;
    private Context mContext;

    public MyBaseExpandableListAdapter(ArrayList<String> gData,ArrayList<ArrayList<Icon>> 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 String getGroup(int groupPosition) {
        return gData.get(groupPosition);
    }

    @Override
    public Icon 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_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));
        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_child, 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;
    }

}

加入布局

<ExpandableListView
        android:id="@+id/exlist_lol"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:childDivider="#E02D2F"/>

MainActivity.java

public class MainActivity extends AppCompatActivity {

    private ArrayList<String> gData = null;
    private ArrayList<ArrayList<Icon>> iData = null;
    private ArrayList<Icon> 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<String>();
        iData = new ArrayList<ArrayList<Icon>>();
        gData.add("工具");
        gData.add("娱乐");
        gData.add("办公");

        //1
        lData = new ArrayList<Icon>();
        lData.add(new Icon(R.drawable.location,"定位"));
        lData.add(new Icon(R.drawable.mike,"录音"));
        lData.add(new Icon(R.drawable.printer, "打印机"));
        lData.add(new Icon(R.drawable.torch,"手电筒"));
        iData.add(lData);
        //2
        lData = new ArrayList<Icon>();
        lData.add(new Icon(R.drawable.game, "游戏"));
        lData.add(new Icon(R.drawable.music, "音乐"));
        iData.add(lData);
        //3
        lData = new ArrayList<Icon>();
        lData.add(new Icon(R.drawable.chat, "聊天"));
        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;
            }
        });

    }
}

8.运行App，展开列表项，点击显示
在这里插入图片描述