Question

I m currently struggling to remove a map item from a list in firebase. E.g. I want to remove item "0" from the list (completely).

I add the single array items in another place via FieldValue.arrayUnion with the updateData Method. This works perfectly fine. In another place in my I then want to have the possibility to remove the item from a list. I load the data via StreamBuilder and display ListTiles via ListView.builder. Now there I tried to replace arrayUnion by arrayRemove, but it doesn t work and I can t figure out why. Here s my code:

onPressed: () async {
  try {
    await Firestore.instance
        .collection( users )
        .document(futSnap.data.uid)
        .collection( trainings )
        .document(widget.trainingID)
        .updateData(
      {
         trainingTitle : widget.trainingTitle,
         trainingID : widget.trainingID,
         trainingDate : widget.trainingDate,
         category : widget.trainingCategory,
         trainingExercises :
            FieldValue.arrayRemove(
          [
            {
               title : trainingExercises[i]
                  [ title ],
               description :
                  trainingExercises[i]
                      [ description ],
               imageURL : trainingExercises[i]
                  [ imageUrl ],
               repetitions :
                  trainingExercises[i]
                      [ repetitions ],
            },
          ],
        )
      },
    );
  } catch (e) {
    print(e);
  }
},

我没有收到任何错误或内容。仍是一个跳板和方案规划,因此将非常赞赏:

Answer 1

由于你的答复,在进一步努力的过程中,现在看来这实际上行之有效:

onPressed: () async {
                              try {
                                await Firestore.instance
                                    .collection( users )
                                    .document(futSnap.data.uid)
                                    .collection( trainings )
                                    .document(widget.trainingID)
                                    .updateData(
                                  {
                                     trainingExercises :
                                        FieldValue.arrayRemove(
                                      [trainingExercises[i]],
                                    )
                                  },
                                );
                              } catch (e) {
                                print(e);
                              }
                            },

但为了公平起见,我并不完全理解为什么由于我的理解以及你的理解,信息必须符合整个地图? 我高兴的是,它发挥了作用,但理解为什么:

Answer 2

消防局没有提供按指数处理阵列内容的任何途径。如果你想从一个阵列中删除一个地图,那么你要么必须知道该阵列的全部内容(exact)。页: 1 FieldValue.arrayRemove()。如果我不得不进行猜测,我可以说,你实际上并没有提供所有“<>可见>值”,因为我们可以看看你重新工作的变量的数值。

如果你没有所有确切的价值观,你就必须阅读整个文件,修改记忆阵列,然后把阵列重新写到文件上。

Answer 3

List<ExpenseData> deleteExpenseData = [];
deleteExpenseData.add(spendingDetailMapList[documentIndex][documentId[documentIndex]][spending]);
expenseCR.doc(documentId[documentIndex]).update({"spending": FieldValue.arrayRemove([deleteExpenseData[0].toJson()],)});

我这样做了。

Answer 4

www.un.org/Depts/DGACM/index_spanish.htm 从上删除特定物体/地图

void removeMapFromFirebase(String documentId, Map<String, dynamic> mapToRemove) {
  
       FirebaseFirestore.instance.collection( yourCollection )
      .doc(documentId)
      .update({
         yourArrayField : FieldValue.arrayRemove([mapToRemove])
      });
}

www.un.org/Depts/DGACM/index_spanish.htm 因此,这里需要把全部物体放在下面的等阵列内。

[mapToRemove]

友情链接