snapshot.data!.keys.elementAt(index); final value = snapshot.data![key]!; return ExpansionTile( title: Text('$key ${value.length} 件'), children: [ for (var license in value) Column( children: [ for (var paragraph in license) Padding( padding: EdgeInsets.only( left: 16.0 * paragraph.indent), child: ListTile( title: Text(paragraph.text), ), ), ], ), ], ); }, ); 23