Android中的Array List的Array获取对象的Firebase对象 [英] Array of Array List in Android to get the Firebase object of object

问题描述

我想通过评分来计算每道菜的平均值，并在条形图中显示，因此我需要使用每道菜的评分值来评估每道菜的值

I want to calculate the average of each dish by their ratings and display in a bar graph, therefore I need the values of each dish with each thier rating

示例3中每个人从用户特定的节点

Example 3 people rated milk as {4,5,3} by each user from the user-specific node linkToJSONTree

我需要一个ArrayList，它可以在其自身列表的每个索引内存储多个列表:

I need an ArrayList which can store multiple lists inside each index of its own listing:

private void letMeCalculate() 
{

    databaseReference = FirebaseDatabase.getInstance().getReference("/Feedback/"+mdate+"/"+mealtime+"/");

    databaseReference.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

            for (DataSnapshot i :  dataSnapshot.getChildren())
            {
                stringArrayList.add(i.getKey());
            }

        }

        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {
        }
    });

    for (String s : stringArrayList)
    {
        databaseReference = FirebaseDatabase.getInstance().getReference("/Feedback/"+mdate+"/"+mealtime+"/"+s+"/");

        databaseReference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

               for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren())
               {
                   NewDishRating newDishRating = dataSnapshot1.getValue(NewDishRating.class);
                   newDishRatingList.add(newDishRating);

               }

            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
            }
        });
    }// end of for loop
}// end of function

推荐答案

我得到了解决方案，而不是使用Array List的Array list，我可以创建genericTypeIndicator，点击此链接即可获得解决方案

I got the solution instead of using Array list of Array List I can create genericTypeIndicator follow this link for the solution

https://stackoverflow.com/a/41503903/5867698

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