如何在flutter中使用cloud firestore发布时获取当前自动生成的文档ID？答案

【问题标题】：How to get current auto generated document ID during posting with cloud firestore in flutter?如何在flutter中使用cloud firestore发布时获取当前自动生成的文档ID？
【发布时间】：2020-04-12 15:21:13
【问题描述】：

我正在使用 firestore 发布位置信息，并在单击按钮时将其数据保存到数据库中。每个按钮单击它都会生成自动DocumnetID，并希望将此ID同时保存到数据库中。

代码：


await firestore.collection("Table_Name").document().setData({
        "SpotLatLong":new GeoPoint(spotlat, spotlong) ,
        "spotName": placeNameController.text,
        "SpotImage":spotImage,
        "UserID":uid,
        "SpotActivity":spotActivity,
        "SpotDocumentID": firestore.collection("Table_Name").document().documentID.toString()//this line generates Different documentID, which is wrong
      }).then((onValue){
        StyleWidget.showToast(msg: "Created spot to the table");
        Navigator.pop(context);
        isLoading = false;
      });

【问题讨论】：

标签： database flutter dart google-cloud-firestore

【解决方案1】：

String id= await firestore.collection("Table_Name").document().documentID().toString;

await firestore.collection("Table_Name").document(id).setData({
        "SpotLatLong":new GeoPoint(spotlat, spotlong) ,
        "spotName": placeNameController.text,
        "SpotImage":spotImage,
        "UserID":uid,
        "SpotActivity":spotActivity,
        "SpotDocumentID":id //this line generates Different documentID, which is wrong
      }).then((onValue){
        StyleWidget.showToast(msg: "Created spot to the table");
        Navigator.pop(context);
        isLoading = false;
      });

希望对此有所帮助

【讨论】：

【解决方案2】：

必须以编程方式将新文档添加到文档 ID，如下所示，

// Your Firestore Database Reference
var tableReference = Firestore.instance.collection("Tables");

// Push a new ID every time like this
var ID = groupReference.document().documentID;

// Set Data to the new Document ID
await firestore.collection("Table_Name").**document(ID)**.setData({
        "SpotLatLong":new GeoPoint(spotlat, spotlong) ,
        "spotName": placeNameController.text,
        "SpotImage":spotImage,
        "UserID":uid,
        "SpotActivity":spotActivity,
        "SpotDocumentID": firestore.collection("AddSpot").document().documentID.toString()//this line generates Different documentID, which is wrong
      }).then((onValue){
        StyleWidget.showToast(msg: "Created spot to the table");
        Navigator.pop(context);
        isLoading = false;
      });

【讨论】：

【解决方案3】：

var docRef = await firestore.collection("Table_Name").document().setData({
        "SpotLatLong":new GeoPoint(spotlat, spotlong) ,
        "spotName": placeNameController.text,
        "SpotImage":spotImage,
        "UserID":uid,
        "SpotActivity":spotActivity,
        "SpotDocumentID": firestore.collection("AddSpot").document().documentID.toString()//this line generates Different documentID, which is wrong
      }).then((onValue){
        StyleWidget.showToast(msg: "Created spot to the table");
        Navigator.pop(context);
        isLoading = false;
      });

通过这种方式获取文档参考

docRef.documentID

【讨论】：

看起来 setData() 返回 void 而不是文档参考