FLUTTER FIRESTORE-查询该字段并获取文档ID并检查其他字段

Question

试图在firestore中的文档字段中获取搜索到的值（用户标识），我想检查此方法但失败的文档的其他字段（状态）

handlesubmit(BuildContext context)async{

final QuerySnapshot searcheduserid=
               await Firestore.instance.collection('users')
            .where('userid',isEqualTo: userid).limit(1).getDocuments();

final userdocid=searcheduserid.documents.map((doc)=>doc.documentID);

final DocumentSnapshot getuserdoc= await Firestore.instance.collection('users')
                      .document(userdocid).get();

final userstatus = getuserdoc.data['status'];
//  I GET AN ERROR HERE ERROR SAYS

// METHOD [](status) was called on null

    if(userstatus==null){
        return showdialog( context,'the entered user id status does not exist');
    }
}

Answer 1

您可能复制了代码的较旧版本，因为您的代码不太可能编译程序的以下行：

final DocumentSnapshot getuserdoc= await Firestore
    .instance
    .collection('users')
    .document(userdocid).get();