<test.com.expandablelistviewdemo.CustomExpandListview //这里不唯一，看你具体把CustomExpandListview放在哪里
android:id="@+id/listView" 
android:layout_width="match_parent" 
android:layout_height="match_parent"></test.com.expandablelistviewdemo.CustomExpandListview>

private String[] parentSource = {"分类1", "分类2", "分类3", "分类4", "分类5"};
private ArrayList<String> parent = new ArrayList<>();
private Map<String, ArrayList<String>> datas = new HashMap<>();

//种类
for (int i = 0; i < parentSource.length; i++) { 
parent.add(parentSource[i]);
}
//给每个种类添加模拟数据
for (int i = 0; i < parent.size(); i++) { 
String str = parent.get(i); 
ArrayList<String> temp = new ArrayList<>(); 
for (int j = 0; j < 20; j++) {  
temp.add("" + j); 
} 
datas.put(str, temp);
}

myAdapter = new MyAdapter(this, parent, datas, listview);
listview.setAdapter(myAdapter);

listview.setHeaderView(getLayoutInflater().inflate(R.layout.indictor_layout, listview, false));

for (int i = 0; i < parent.size(); i++) { 
listview.expandGroup(i);
}

listview.setOnChildClickListener(new ExpandableListView.OnChildClickListener() { 
@Override 
public boolean onChildClick(ExpandableListView expandableListView, View view, int i, int i1, long l) {  
 Toast.makeText(MainActivity.this, "点击了第" + (i + 1) + " 类的第" + i1 + "项", Toast.LENGTH_SHORT).show();  
 return true; 
 }
}
);