恢复缓存数据RecycerView+Firestore

Question

第一个活动是一个新闻提要屏幕，其中使用RecycerView+Firestore。我启用了设置离线选项。

问题：

 /*Firebase*/
        mDb = FirebaseFirestore.getInstance();
        mDb.collection("IndexTimeline_User").document(mCurrentUser.getUid()).collection("Posts").get().addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
            @Override
            public void onSuccess(QuerySnapshot documentSnapshots) {

                mQuery = documentSnapshots.getQuery();
                mCardFeedList.setAdapter(mAdapter);


            }
        });
        mDb.setFirestoreSettings(settings);


        /* Recycler */
        mCardFeedList = (RecyclerView) view.findViewById(R.id.explore_tab1_list);
        mCardFeedList.setHasFixedSize(true);
        mCardFeedList.setItemViewCacheSize(20);
        mCardFeedList.setDrawingCacheEnabled(true);

        mAdapter = new PostsExploreTab1Adapter(mQuery, this){

            @Override
            protected void onDataChanged() {

                if (getItemCount() == 0) {
                    mCardFeedList.setVisibility(View.GONE);
                    mProgressBar.setVisibility(View.GONE);
                    //mTxtVazio.setVisibility(View.VISIBLE);

                } else {
                    mCardFeedList.setVisibility(View.VISIBLE);
                    mProgressBar.setVisibility(View.GONE);
                    //mTxtVazio.setVisibility(View.GONE);
                }


            }
        };

        llmanager = new LinearLayoutManager(getActivity());
        mCardFeedList.setLayoutManager(llmanager);




        /*INICIADO O RECYCLERVIEW E ADAPTER*/
        if (mAdapter != null) {
            mAdapter.startListening();

        }

Answer 1

从数据库获取数据时，请使用AddonSuccessListener并仅在从数据库加载数据时设置适配器。这意味着您将从缓存中读取数据，并且只有当新数据完全加载时才会将其添加到RecycerView中。您的代码应该如下所示：

yourRef.get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
    @Override
    public void onSuccess(DocumentSnapshot documentSnapshot) {
        //get data
        mCardFeedList.setAdapter(mAdapter);
    }
});