DatabaseException:无法将类型为java.lang.String的对象转换为Models.OrderDetails

问题描述

这是我的数据库结构.我正在尝试获取订单详细信息.

This is my database structure. I am trying to fetch Order Details.

这是代码

 databaseReference = FirebaseDatabase.getInstance().getReference().child("Admin Order").
            child(userID);
    databaseReference.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
            for (DataSnapshot childSnapshot: dataSnapshot.getChildren()){
                for (DataSnapshot grandchild : childSnapshot.child("Order Details").getChildren()){
                    OrderDetails details = grandchild.getValue(OrderDetails.class);
                    mList.add(details);
                    progressBar.setVisibility(View.INVISIBLE);
                }
            }
            adapter = new PreviousOrderAdapter(getContext(), mList);
            recyclerView.setAdapter(adapter);
        }

        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {
            progressBar.setVisibility(View.INVISIBLE);
        }
    });

但是我收到此错误

这是我收到错误的行

OrderDetails details = grandchild.getValue(OrderDetails.class);

如果我从(DataSnapshot孙子:childSnapshot.child(订单详细信息").getChildren())的中删除 .child(订单详细信息).该代码有效，但它还会显示 Products 的子代，其所有值均为null.这是屏幕截图.

If I remove .child(Order Details) from for (DataSnapshot grandchild : childSnapshot.child("Order Details").getChildren()). The Code works but it also show the child of Products with all value as null. Here is a Screenshot.

有什么帮助或建议吗?

推荐答案

问题是您正在尝试将字符串( OrderDetails 中的值)转换为 OrderDetails 对象

The problem is you are trying to convert a string ( the values in OrderDetails) to OrderDetails object

解决方案:

databaseReference = FirebaseDatabase.getInstance().getReference().child("Admin Order").
            child(userID);
    databaseReference.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
            for (DataSnapshot childSnapshot : dataSnapshot.getChildren()) {
                OrderDetails orderDetails = childSnapshot.child("Order Details").getValue(OrderDetails.class);
                Log.w("orderDetails", orderDetails.getConsumer());
                mList.add(details);
                progressBar.setVisibility(View.INVISIBLE);
            }
            adapter = new PreviousOrderAdapter(getContext(), mList);
            recyclerView.setAdapter(adapter);
        }

        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {
            progressBar.setVisibility(View.INVISIBLE);
        }
    });

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