Android Firebase根据群组成员资格创建列表

Question

Android Firebase根据群组成员资格创建列表

ImA*_*lay 8 android firebase firebase-realtime-database

我正在尝试创建一个仅包含特定组项的列表.例如,我自己在数据库控制台(包括组的键)中创建/编写了"fruits"节点和"groups"节点.

对Firebase来说相对较新,所以仍然试图将我的数据结构展平.

JSON(显示"水果"和"组")如下所示:

 {
  "fruits" : {
    "apple" : {
      "color" : "appleColorValueHere",
      "groups" : {
        "GroupABCKey" : true,
        "GroupXYZKey" : true
      },
      "origin" : "appleOriginValueHere",
      "size" : "appleSizeValueHere"
    },
    "orange" : {
      "color" : "orangeColorValueHere",
      "groups" : {
        "GroupABCKey" : true,
        "GroupXYZ" : true
      },
      "origin" : "orangeOriginValueHere",
      "size" : "orangeSizeValueHere"
    },
    "strawberry" : {
      "color" : "strawberryColorValueHere",
      "groups" : {
        "GroupJKLKey" : true
      },
      "origin" : "strawberryOriginValueHere",
      "size" : "strawberrySizeValueHere"
    }
  },
  "groups" : {
    "GroupABCKey" : {
      "members" : {
        "apple" : true,
        "orange" : true
      },
      "name" : "Group ABC Name Here"
    },
    "GroupJKLKey" : {
      "members" : {
        "strawberry" : true
      },
      "name" : "Group JKL Name Here"
    },
    "GroupXYZKey" : {
      "members" : {
        "apple" : true,
        "orange" : true
      },
      "name" : "Group XYZ Name Here"
    }
  }    ...
        ...
}

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在应用程序本身中,用户可以创建一个列表,将整个fruits节点复制到新创建的列表中(请参阅下面的JSON user-list-items).我然后使用显示项目FirebaseRecyclerAdapter

这是我如何做的代码:

private void writeNewFruitList(String userId, String username, String email, String title) {
    final String key = databaseReference.child("fruit-lists").push().getKey();
    UserLists userLists = new UserLists(userId, username, email, title);

    HashMap<String, Object> updatedListToAddMap = new HashMap<>();
    HashMap<String, Object> itemToAdd =
            (HashMap<String, Object>) new ObjectMapper().convertValue(userLists, Map.class);
    updatedListToAddMap.put("/fruit-lists/" + key, itemToAdd);
    updatedListToAddMap.put("/user-fruit-lists/" + userId + "/" + key, itemToAdd);

    databaseReference.updateChildren(updatedListToAddMap);

    final DatabaseReference subDatabaseReference = FirebaseDatabase.getInstance().getReference();
    subDatabaseReference.child("fruits").addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            for (DataSnapshot child : dataSnapshot.getChildren()) {
                Log.d(TAG, child.getKey());
                Log.d("fruitValues::", dataSnapshot.getValue().toString());
                final String fruitKey= child.getKey();
                FruitModel fruitModel = child.getValue(FruitModel.class);

                Map<String, Object> nodeValues = fruitModel.toMap();
                Map<String, Object> childUpdates = new HashMap<>();

                String new_path = "/user-list-items/" + key + "/" + fruitKey+ "/";
                childUpdates.put(new_path, nodeValues);
                subDatabaseReference.updateChildren(childUpdates);

            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {
            Log.e(TAG, "onCancelled", databaseError.toException());
        }
    });
}

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问:如何使用组实现此过程？例如,用户创建列表并且仅希望新创建的列表包含GroupABCKey但是他们还想要那些结果(大小,来源等)的细节.

Q2:编辑我FruitModel.java的帐户的最佳方法是什么？

public class FruitModel {
    public String size;
    public String origin;
    public String color;

    public FruitModel() {
    }

    public FruitModel(String size, String origin, String color) {
        this.size = size;
        this.origin = origin;
        this.color = color;
    }

    @Exclude
    public Map<String, Object> toMap() {
        HashMap<String, Object> result = new HashMap<>();

        result.put("size", size);
        result.put("origin", origin);
        result.put("color", color);

        return result;
    }
    // getters & setters
}

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最后,这里就是我相信的user-list-items节点会看起来像如果操作正确？

listKey1forUserA是我正确创建的(除了前面提到的映射组).

listKey2forUserA是我想要完成的 - 用户想要仅使用"GroupJKLKey"中的项目创建和填充列表

  "user-list-items" : {
    "listKey1forUserA" : {
      "apple" : {
        "color" : "appleColorValueHere",
        "groups" : {
          "GroupABCKey" : true,
          "GroupXYZ" : true
        },
        "origin" : "appleOriginValueHere",
        "size" : "appleSizeValueHere"
      },
      "orange" : {
        "color" : "orangeColorValueHere",
        "groups" : {
          "GroupABCKey" : true,
          "GroupXYZKey" : true
        },
        "origin" : "orangeOriginValueHere",
        "size" : "orangeSizeValueHere"
      },
      "strawberry" : {
        "color" : "strawberryColorValueHere",
        "groups" : {
          "GroupJKLKey" : true
        },
        "origin" : "strawberryOriginValueHere",
        "size" : "strawberrySizeValueHere"
      }
    },
    "listKey2forUserA" : {
      "strawberry" : {
        "color" : "strawberryColorValueHere",
        "groups" : {
          "GroupJKLKey" : true
        },
        "origin" : "strawberryOriginValueHere",
        "size" : "strawberrySizeValueHere"
      }
    }
  }

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这是解决这个问题的正确方法吗？任何帮助或正确方向上的一点都会很棒.

Answer 1

ImA*_*lay 0

尽管自我最初发布此问题以来我的用法略有变化，但经过一些细微调整后，下面的两个用例仍然适用。可能有更好的方法来解决这个问题，所以我绝对欢迎其他人的任何建议或想法。

总而言之，您以具有groups路径和users路径的方式构建数据库。该users路径不包含对组的引用。获取特定组的子项的数据快照（只需要键）并将它们添加到 ArrayList 中。> 对于 ArrayList 中的每个项目，将其插入路径中users。

然后，这将允许访问这些用户的详细信息（或水果，如我原来的问题中所使用的），并能够显示该信息或创建您认为合适的新信息。

根据组成员身份创建/写入人员列表：

private void writeListFromGroupMembership(){ final DatabaseReference mainPathReference = FirebaseDatabase.getInstance().getReference(); final ArrayList<String> groupMembers = new ArrayList<>(); DatabaseReference groupsReference = FirebaseDatabase.getInstance().getReference() .child("groups") .child("someOtherChildYouMayHave") .child("nameOfGroupYouAreInterestedIn"); /* Step 1: Get a list of people in a specific group that you are interested in */ groupsReference.addListenerForSingleValueEvent(new ValueEventListener() { @Override public void onDataChange(DataSnapshot dataSnapshot) { for (DataSnapshot child : dataSnapshot.getChildren()) { String groupMemberKey = child.getKey(); if (child.getValue(Boolean.class) != null) { groupMembers.add(groupMemberKey); } else { // TODO } } /* Step 2: Loop through your list of people and insert them as a child like the following: */ for (int i = 0; i < groupMembers.size(); i++) { final String singleGroupMember = groupMembers.get(i); mainPathReference.child("all-groups").child("anotherChildYouMayHave").child(singleGroupMember) .addListenerForSingleValueEvent(new ValueEventListener() { @Override public void onDataChange(DataSnapshot dataSnapshot) { // Make a POJO for the item and immediately turn it into a HashMap Person person= dataSnapshot.getValue(Person.class); Map<String, Object> nodeValues = person.toMap(); // Make a map for the items you are adding Map<String, Object> childUpdates = new HashMap<>(); // The path where the items will be copied/written to. String newPath = "/master-list-items/" + listKey + "/" + singleGroupMember + "/"; // Add the items to the update map childUpdates.put(newPath, nodeValues); // Do the update mainPathReference.updateChildren(childUpdates); } @Override public void onCancelled(DatabaseError databaseError) { Log.w(TAG, "onCancelled: ", databaseError.toException()); } }); } } // your other onCancelled override method here }
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根据组成员身份显示人员列表（例如使用 Spinner）：

public List<Person> persons; ... private void getGroupMembers(String groupSelected) { groupRef= FirebaseDatabase.getInstance().getReference() .child("someOtherChildThatYouHouseGroupsUnder") .child(groupSelected) .child("members"); groupRef.addListenerForSingleValueEvent(new ValueEventListener() { @Override public void onDataChange(DataSnapshot dataSnapshot) { for (DataSnapshot child : dataSnapshot.getChildren()) { String groupMember= child.getKey(); selectedGroupMembers.add(groupMember); } for (int i = 0; i < selectedGroupMembers.size(); i++) { String singleMember = selectedGroupMembers.get(i); singleMemberDatabaseReference = FirebaseDatabase.getInstance().getReference() .child("all-people") .child(singleMember); singleMemberDatabaseReference .addListenerForSingleValueEvent(new ValueEventListener() { @Override public void onDataChange(DataSnapshot dataSnapshot) { Person person = dataSnapshot.getValue(Person.class); persons.add(person); personAdapter = new PersonAdapter(getApplicationContext(), persons); recyclerView.setAdapter(personAdapter); } @Override public void onCancelled(DatabaseError databaseError) { Log.w(TAG,"onCancelled: ", databaseError.toException()); } }); } } @Override public void onCancelled(DatabaseError databaseError) { Log.w(TAG, "onCancelled: ", databaseError.toException()); } }); }
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为了根据组成员身份显示人员列表，我的数据库结构类似于：

{ "all-groups":{ "groupNameorKeyOfGroupName":{ "details":{ "meetingLocation":"110 William Street", "someOtherChild":"Your value" }, "members":{ "fakeUserA":true, "fakeUserB":true, "fakeUserC":true, "fakeUserD":true } } } "all-users":{ "fakeUserA":{ }, "fakeUserB":{ } } }
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