Firestore文档参考数组 [英] Firestore Array of Document References

问题描述

我的Firestore数据库具有以下结构:

I have the following structure of my Firestore database:

products:{ // Collection
    procuct_1: { // Document
       title:"",
       url:""

videos:{ // Collection
    video_1:{ // Document
       title:"",
       products:{ // Array of references 
            0: "/products/product_1,
            1: "/products/product_2

我希望能够从视频收藏夹中的数组"字段获取对产品收藏夹的文档引用，以便获取此收藏夹中某些字段的值(例如产品标题).

I would like to be able from Array field in Videos Collection to get Document References to Products collection in order to get values of some fields of this collection (ex. title of product).

目前我使用此代码:

    FirebaseFirestore firebaseFirestore = FirebaseFirestore.getInstance();
    firebaseFirestore
            .collection("videos")
            .get()
            .addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
                @Override
                public void onComplete(@NonNull Task<DocumentSnapshot> task) {
                    if (task.isSuccessful()) {
                        DocumentSnapshot documentSnapshot = task.getResult();

                        Map<String, Object> map = documentSnapshot.getData();
                        for (Map.Entry<String, Object> entry: map.entrySet()){
                            if (entry.getKey().equals("products")){
                               textView.setText(entry.getValue().toString());
                            }
                        }

但是entry.getValue().toString()向我返回了这样的数组:

But entry.getValue().toString(), returns me such array:

[com.google.firebase.firestore.DocumentReference@451d5ae8,

com.google.firebase.firestore.DocumentReference@e28cd0c]

关于如何从此数组中获取产品集合的任何字段的任何建议?

Any suggestions how I can get any field of Product collection from this Array?

推荐答案

要解决此问题，请使用以下代码:

To solve this, please use the following code:

firebaseFirestore.collection("videos")
    .get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
        @Override
        public void onComplete(@NonNull Task<QuerySnapshot> task) {
            for (DocumentSnapshot document : task.getResult()) {
                List<String> products = (List<String>) document.get("products");
                for (String product : products) {
                    Log.d("TAG", product);
                }
            }
        }
    });

输出将是:

/products/product_1
/products/product_2

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