BaseExpandableListAdapter：支持动态加载

layout-item_child:

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:orientation="vertical"
    android:gravity="center_vertical"
    android:paddingLeft="50dp">

    <TextView
        android:id="@+id/child"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

layout-item_group:

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:gravity="center_vertical"
    android:paddingLeft="30dp">左边偏移30，显示三角形

    <TextView
        android:id="@+id/group"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

SecondActivity:

public class SecondActivity extends Activity {

    private ExpandableListView expandableListView;

    private MyDemoBaseExpandableListAdapter adapter;

    String groupStringArr[]={"腾讯","百度","阿里"};
    String childStringArrs[][]={
            {"QQ","微信","QQ浏览器"},
            {"百度一下","百度地图","百度外卖"},
            {"淘宝","支付宝"}
    };

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

        expandableListView=(ExpandableListView)findViewById(R.id.my_elv);

        adapter=new MyDemoBaseExpandableListAdapter();
        expandableListView.setAdapter(adapter);


    }

    class MyDemoBaseExpandableListAdapter extends BaseExpandableListAdapter{//重点

        @Override
        public int getGroupCount() {
            return groupStringArr.length;
        }

        @Override
        public int getChildrenCount(int i) {
            return childStringArrs[i].length;
        }

        @Override
        public Object getGroup(int i) {
            return groupStringArr[i];
        }

        @Override
        public Object getChild(int i, int i1) {
            return childStringArrs[i][i1];
        }

        @Override
        public long getGroupId(int i) {
            return i*100;
        }

        @Override
        public long getChildId(int i, int i1) {
            return i*100+i1;
        }

        @Override
        public boolean hasStableIds() {
            return false;
        }

        @Override
        public View getGroupView(int i, boolean b, View view, ViewGroup viewGroup) {//动态加载

            View view1= LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.item_group,null);

            TextView textView=(TextView)view1.findViewById(R.id.group);

            Object data=getGroup(i);

            textView.setText((String)data);

            if(i%2==1){
                textView.setTextColor(Color.RED);//颜色
            }
            else{
                textView.setTextColor(Color.BLUE);
            }

            return view1;
        }

        @Override
        public View getChildView(int i, int i1, boolean b, View view, ViewGroup viewGroup) {

            View view1= LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.item_child,null);

            TextView textView=(TextView)view1.findViewById(R.id.child);


            Object data=getChild(i,i1);

            textView.setText((String)data);

            if(i1>1){
                textView.setTextSize(TypedValue.COMPLEX_UNIT_DIP,50);//字体大小
            }
            else{
                textView.setTextSize(TypedValue.COMPLEX_UNIT_DIP,20);
            }

            return view1;

        }

        @Override
        public boolean isChildSelectable(int i, int i1) {
            return false;
        }
    }
    
}