android - 如何为从 Firestore 填充的 RecyclerView 实现过滤器？

Question

通过用更新的查询替换适配器来实时过滤从 Firestore 填充的 RecyclingView 显示出非常差的性能。

要在我的应用程序中实时过滤 RecyclerView(onQueryTextChange)，我正在使用扩展 FirestoreRecyclerAdapter 的自定义适配器，每次我需要过滤数据 我创建一个新的 Query 对象，创建新的 FirestoreRecyclerOptions 对象，然后创建我的自定义适配器对象，我将 FirestoreRecyclerOptions 对象传递给 FirestoreRecyclerAdapter 构造函数，最后我在我的 RecyclerView 上调用了 swapAdapter。这种方法的问题在于它会导致性能不佳。每次更新查询时，我都可以看到 View 在闪烁。

DocumentSearchActivity.java

package com.example.testapp;

import android.app.Activity;
import android.app.SearchManager;
import android.arch.lifecycle.LifecycleOwner;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.View;
import android.view.animation.AnimationUtils;
import android.view.animation.LayoutAnimationController;
import android.view.inputmethod.InputMethodManager;
import android.widget.SearchView;
import android.widget.TextView;

import com.example.testapp.adapter.ItemAdapter;
import com.example.testapp.model.Item;
import com.firebase.ui.firestore.FirestoreRecyclerOptions;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.Query;

public class DocumentSearchActivity extends AppCompatActivity {
    private static final String TAG = DocumentSearchActivity.class.getSimpleName();
    private RecyclerView mRecyclerView;
    private ItemAdapter mAdapter;
    private RecyclerView.LayoutManager mLayoutManager;
    private TextView mNoResultsTextView;
    private SearchView mSearchView;
    private FirestoreQuery mQuery;
    private Toolbar mToolbar;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_document_search);
        mToolbar = findViewById(R.id.app_bar);
        setSupportActionBar(mToolbar);
        getSupportActionBar().setDisplayShowTitleEnabled(false);
        mRecyclerView = findViewById(R.id.recycler_view);
        mSearchView = findViewById(R.id.search_bar);
        mNoResultsTextView = findViewById(R.id.result);
        mNoResultsTextView.setVisibility(View.GONE);
        if(getIntent().hasExtra(MainActivity.QUERY_EXTRA)){
            mSearchView.setQuery(getIntent().getStringExtra(MainActivity.QUERY_EXTRA), true);
            mSearchView.requestFocus();
        }

        mQuery = new FirestoreQuery(this, "");
        mLayoutManager = new LinearLayoutManager(this);
        mRecyclerView.setLayoutManager(mLayoutManager);

        Intent intent = getIntent();
        if(Intent.ACTION_SEARCH.equals(intent.getAction())) {
            mQuery.setQueryString(intent.getStringExtra(SearchManager.QUERY));
        }

        mAdapter = new ItemAdapter(mQuery.getOptions());
        mRecyclerView.setAdapter(mAdapter);
        mSearchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String query) {
                return true;
            }

            @Override
            public boolean onQueryTextChange(String newText) {
                mAdapter = new ItemAdapter(mQuery.setQueryString(newText).getOptions());
                mRecyclerView.swapAdapter(mAdapter, true);
                mAdapter.notifyDataSetChanged();
                mAdapter.startListening();
                return true;
            }
        });
    }

    private void runLayoutAnimation(final RecyclerView recyclerView) {
        final Context context = recyclerView.getContext();
        final LayoutAnimationController controller =
                AnimationUtils.loadLayoutAnimation(context, R.anim.layout_animation_fall_down);

        recyclerView.setLayoutAnimation(controller);
        recyclerView.getAdapter().notifyDataSetChanged();
        recyclerView.scheduleLayoutAnimation();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.actions_document_search_activity, menu);
        return super.onCreateOptionsMenu(menu);
    }

    private class FirestoreQuery {
        private LifecycleOwner mLifecycleOwner;
        private String mQueryString;
        private Query mQuery;
        private FirestoreRecyclerOptions<Item> mOptions;

        public FirestoreQuery(LifecycleOwner lifecycleOwner, String query) {
            mLifecycleOwner = lifecycleOwner;
            setQueryString(query);
        }

        public FirestoreQuery setQueryString(String queryString) {
            if(queryString.length() != 0)
                this.mQueryString = queryString.substring(0,1).toUpperCase() + queryString.substring(1).toLowerCase();
            else
                this.mQueryString = queryString;
            updateQuery();
            updateOptions();
            return this;
        }

        private void updateOptions() {
            mOptions = new FirestoreRecyclerOptions.Builder<Item>()
                    .setQuery(mQuery, Item.class)
                    .setLifecycleOwner(mLifecycleOwner)
                    .build();
        }

        private void updateQuery() {
            if(mQueryString.isEmpty()){
                this.mQuery = FirebaseFirestore.getInstance()
                        .collection("tubes_test")
                        .orderBy("number");
            } else {
                StringBuilder query_lower = new StringBuilder(mQueryString.length());
                query_lower.append(mQueryString);
                query_lower.setCharAt(mQueryString.length() - 1, (char) (query_lower.charAt(mQueryString.length() - 1) + 1));
                if (mQueryString.matches("^[0-9]{1,3}[A-Z]*$")) {
                    this.mQuery = FirebaseFirestore.getInstance()
                            .collection("tubes_test")
                            .whereGreaterThanOrEqualTo("number", mQueryString)
                            .whereLessThan("number", query_lower.toString());
                } else {
                    this.mQuery = FirebaseFirestore.getInstance()
                            .collection("tubes_test")
                            .whereGreaterThanOrEqualTo("name", mQueryString)
                            .whereLessThan("name", query_lower.toString());
                }
            }
        }

        public FirestoreRecyclerOptions<Item> getOptions() {
            return mOptions;
        }

    }
}

ItemAdapter.java

package com.example.testapp.adapter;

import android.content.Context;
import android.content.Intent;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;

import com.example.testapp.DocumentViewerActivity;
import com.example.testapp.R;
import com.example.testapp.model.Item;
import com.firebase.ui.firestore.FirestoreRecyclerAdapter;
import com.firebase.ui.firestore.FirestoreRecyclerOptions;

public class ItemAdapter extends FirestoreRecyclerAdapter<Item, ItemAdapter.ItemHolder> {

    public ItemAdapter(@NonNull FirestoreRecyclerOptions<Item> options) {
        super(options);
    }

    @Override
    protected void onBindViewHolder(@NonNull ItemHolder holder, int position, @NonNull Item item) {
        final String tubeNumber = item.getNumber();
        holder.mNumberTextView.setText(item.getNumber());
        holder.mNameTextView.setText(item.getName());
        holder.mFormulaTextView.setText(item.getFormula());
        holder.mRangeTextView.setText(item.getRange());
        holder.mInfoButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(v.getContext(), DocumentViewerActivity.class);
                intent.putExtra("number", tubeNumber);
                intent.putExtra("doctype", "info");
                v.getContext().startActivity(intent);
            }
        });
        holder.mManualButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(v.getContext(), DocumentViewerActivity.class);
                intent.putExtra("number", tubeNumber);
                intent.putExtra("doctype", "manual");
                v.getContext().startActivity(intent);
            }
        });
    }

    @NonNull
    @Override
    public ItemHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        Context context = viewGroup.getContext();
        LayoutInflater inflater = LayoutInflater.from(context);

        View tubeView = inflater.inflate(R.layout.item_tube, viewGroup, false);

        return new ItemHolder(tubeView);
    }

    public static class ItemHolder extends RecyclerView.ViewHolder {
        public TextView mNumberTextView;
        public TextView mNameTextView;
        public TextView mFormulaTextView;
        public TextView mRangeTextView;
        public Button mInfoButton;
        public Button mManualButton;

        public ItemHolder(View itemView){
            super(itemView);

            mNumberTextView = itemView.findViewById(R.id.number);
            mNameTextView = itemView.findViewById(R.id.name);
            mFormulaTextView = itemView.findViewById(R.id.formula);
            mRangeTextView = itemView.findViewById(R.id.range);
            mInfoButton = itemView.findViewById(R.id.info_btn);
            mManualButton = itemView.findViewById(R.id.manual_btn);
        }
    }
}

不知道有没有更好的办法解决这个问题。此外，我不想失去 Firestore 的功能，例如实时数据更新和离线访问数据库。我正在考虑在我的适配器中使用可过滤列表，问题是我如何使它与 Firestore 保持同步。请分享您的见解和指南。

Answer 1

这是对我有用的解决方案。基本上，我创建了一个自定义可过滤适配器，我只用来自 Firestore 的数据填充一次。

CustomItemAdapter.java

package com.example.testapp.adapter;

import android.content.Intent;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Filter;
import android.widget.Filterable;
import android.widget.TextView;

import com.example.testapp.DocumentViewerActivity;
import com.example.testapp.R;
import com.example.testapp.model.Item;

import java.util.ArrayList;
import java.util.List;

public class CustomItemAdapter extends RecyclerView.Adapter<CustomItemAdapter.ItemHolder> implements Filterable {

    private List<Item> mTubeList;
    private List<Item> mTubeListFiltered;

    public CustomItemAdapter(List<Item> tubeList){
        mTubeList = tubeList;
        mTubeListFiltered = tubeList;
    }

    @NonNull
    @Override
    public ItemHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        View tubeView = LayoutInflater.from(viewGroup.getContext())
                .inflate(R.layout.item_tube, viewGroup, false);
        return new ItemHolder(tubeView);
    }

    @Override
    public void onBindViewHolder(@NonNull ItemHolder holder, int i) {
        final Item item = mTubeListFiltered.get(i);
        //Setting up view
    }

    @Override
    public int getItemCount() {
        return mTubeListFiltered.size();
    }

    @Override
    public Filter getFilter() {
        return new Filter() {
            @Override
            protected FilterResults performFiltering(CharSequence constraint) {
                String pattern = constraint.toString().toLowerCase();
                if(pattern.isEmpty()){
                    mTubeListFiltered = mTubeList;
                } else {
                    List<Item> filteredList = new ArrayList<>();
                    for(Item tube: mTubeList){
                        if(tube.getNumber().toLowerCase().contains(pattern) || tube.getName().toLowerCase().contains(pattern)) {
                            filteredList.add(tube);
                        }
                    }
                    mTubeListFiltered = filteredList;
                }

                FilterResults filterResults = new FilterResults();
                filterResults.values = mTubeListFiltered;
                return filterResults;
            }

            @Override
            protected void publishResults(CharSequence constraint, FilterResults results) {
                mTubeListFiltered = (ArrayList<Item>) results.values;
                notifyDataSetChanged();
            }
        };
    }

    public static class ItemHolder extends RecyclerView.ViewHolder {
        //ViewHolder's code
    }
}

Activity fragment :

        Query query = FirebaseFirestore.getInstance()
                .collection("test")
                .orderBy("number");
        query.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
            @Override
            public void onComplete(@NonNull Task<QuerySnapshot> task) {
                mAdapter = new CustomItemAdapter(task.getResult().toObjects(Item.class));
                mRecyclerView.setAdapter(mAdapter);
            }
        });
        mSearchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String query) {
                return true;
            }

            @Override
            public boolean onQueryTextChange(String newText) {
                mAdapter.getFilter().filter(newText);
                return true;
            }
        });