RecyclerView实现底部载入很多其它功能-白红宇

RecyclerView实现底部载入很多其它功能

阅读量：4618 次

发布时间：2019-06-09

本文共 12237 字，大约阅读时间需要 40 分钟。

这两天在公司没有什么任务分配，就研究了下咱们Google在Android5.0 推出的一个用来取代ListView的列表控件----RecyclerView。

发现功能上确实比ListView强大了不少，可扩展性也增强了不少。

可是使用过RecyclerView的Programmers应该都知道，RecyclerView无法直接代码加入头布局和脚布局。

那么他喵的怎么样实现最经常使用的底部载入很多其它数据呢？带着这种疑惑我在StackOverFlow上搜索到了一个有參考价值的答案并写了一个Demo实现了它。

參考链接附上：http://stackoverflow.com/questions/30681905/adding-items-to-endless-scroll-recyclerview-with-progressbar-at-bottom?answertab=active#tab-top

废话不多说。開始进入正题，直接上代码。

第一步：创建两个接口

public interface LoadMoreDataListener {    public abstract void loadMoreData();}

public interface RecyclerOnItemClickListener {    public abstract void onClick(View view);}

第二步：依据XML中的布局来创建一个Activity

public class MainActivity extends AppCompatActivity {    private RecyclerView mRecyclerView;    private TextView tv_empty;    private List
     
       list = new ArrayList<>();    private List
      
        moreData = new ArrayList<>();    private List
       
         refreshData = new ArrayList<>();    private MyAdapter myAdapter;    private Handler handler = new Handler();    private SwipeRefreshLayout sfl;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);        setSupportActionBar(toolbar);        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);        fab.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                 TODO: 点击FAB后的操作            }        });        init();    }    private void init() {        initData();        initRefreshData();        initMoreData();        initView();        initListener();    }    private void initView() {        mRecyclerView = (RecyclerView) findViewById(R.id.mRecyclerView);        tv_empty = (TextView) findViewById(R.id.tv_empty);        sfl = (SwipeRefreshLayout) findViewById(R.id.sfl);        sfl.setColorSchemeColors(Color.parseColor("#FF4081"));        //创建一个LinearLayoutManager对象        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);        mRecyclerView.setLayoutManager(linearLayoutManager);        //创建adapter对象        myAdapter = new MyAdapter(this, mRecyclerView);        mRecyclerView.setAdapter(myAdapter);        myAdapter.setData(list);//设置数据        if (list.isEmpty()) {            mRecyclerView.setVisibility(View.GONE);            tv_empty.setVisibility(View.VISIBLE);        } else {            mRecyclerView.setVisibility(View.VISIBLE);            tv_empty.setVisibility(View.GONE);        }    }    //初始化数据    private void initData() {        for (int i = 0; i < 20; i++) {            list.add("handsome is wrong?" + i);        }    }    //初始化载入很多其它数据    private void initMoreData() {        for (int i = 0; i < 10; i++) {            moreData.add("life is good" + i);        }    }    private void initRefreshData() {        for (int i = 0; i < 2; i++) {            refreshData.add("refreshData" + i);        }    }    //初始化监听    private void initListener() {        sfl.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {            @Override            public void onRefresh() {                //模拟下拉刷新数据操作                handler.postDelayed(new Runnable() {                    @Override                    public void run() {                        list.addAll(0, refreshData);                        myAdapter.notifyDataSetChanged();                        sfl.setRefreshing(false);                    }                }, 1000);            }        });        //载入很多其它回调监听        myAdapter.setOnMoreDataLoadListener(new LoadMoreDataListener() {            @Override            public void loadMoreData() {                //增加null值此时adapter会推断item的type                list.add(null);                myAdapter.notifyDataSetChanged();                handler.postDelayed(new Runnable() {                    @Override                    public void run() {                        //移除刷新的progressBar                        list.remove(list.size() - 1);                        myAdapter.notifyDataSetChanged();                        list.addAll(moreData);                        myAdapter.notifyDataSetChanged();                        myAdapter.setLoaded();                    }                }, 2000);            }        });        myAdapter.setOnItemClickListener(new RecyclerOnItemClickListener() {            @Override            public void onClick(View view) {                //Toast.makeText(MainActivity.this, "能不能不要这么帅", Toast.LENGTH_SHORT).show();                Snackbar.make(view, "Iam BadGuy_Leo", Snackbar.LENGTH_SHORT).show();            }        });    }}

activity_main

> <android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:fitsSystemWindows="true" tools:context="com.byzk.loadmorerecyclerview.MainActivity"> <android.support.design.widget.AppBarLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:theme="@style/AppTheme.AppBarOverlay"> <android.support.v7.widget.Toolbar android:id="@+id/toolbar" android:layout_width="match_parent" android:layout_height="?attr/actionBarSize" android:background="?attr/colorPrimary" app:popupTheme="@style/AppTheme.PopupOverlay" /> </android.support.design.widget.AppBarLayout> <include layout="@layout/content_main" /> <android.support.design.widget.FloatingActionButton android:id="@+id/fab" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="bottom|end" android:layout_margin="@dimen/fab_margin" android:src="@android:drawable/ic_dialog_email" /> </android.support.design.widget.CoordinatorLayout>

content_main

> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" app:layout_behavior="@string/appbar_scrolling_view_behavior" tools:context="com.byzk.loadmorerecyclerview.MainActivity" tools:showIn="@layout/activity_main"> <android.support.v4.widget.SwipeRefreshLayout android:id="@+id/sfl" android:layout_width="match_parent" android:layout_height="match_parent"> <android.support.v7.widget.RecyclerView android:id="@+id/mRecyclerView" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_margin="5dp" android:padding="5dp" android:scrollbars="vertical"> </android.support.v7.widget.RecyclerView> </android.support.v4.widget.SwipeRefreshLayout> <TextView android:id="@+id/tv_empty" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" android:text="暂无数据" android:textColor="@color/colorAccent" android:visibility="gone" /> </RelativeLayout>

创建RecyclerView的条目布局 item_view

android:selectableItemBackground" android:gravity="center"> <TextView android:id="@+id/tv_name" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" android:layout_margin="5dp" android:text="Name" android:textColor="@android:color/black" android:textSize="18sp" /> </RelativeLayout> </android.support.v7.widget.CardView>

创建脚布局item_footer

第三步：创建一个RecyclerView的Adapter 这一步是很关键的一步。使用过RecyclerView的programmer应该都知道它无法设置条目点击事件——！

所以必须自己写一个接口回调，来自己定制点击事件。代码例如以下

/** * Author: lihongxiang * Time: 上午 11:14 * Email:lihongxiangleo@163.com */public class MyAdapter extends RecyclerView.Adapter {    private static final int VIEW_ITEM = 0;    private static final int VIEW_PROG = 1;    private final Context mContext;    private final RecyclerView mRecyclerView;    private List
     
       mData;    private final LayoutInflater inflater;    private boolean isLoading;    private int totalItemCount;    private int lastVisibleItemPosition;    //当前滚动的position以下最小的items的临界值    private int visibleThreshold = 5;    public MyAdapter(Context context, RecyclerView recyclerView) {        mContext = context;        inflater = LayoutInflater.from(context);        mRecyclerView = recyclerView;        if (mRecyclerView.getLayoutManager() instanceof LinearLayoutManager) {            final LinearLayoutManager linearLayoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();            //mRecyclerView加入滑动事件监听            mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {                @Override                public void onScrolled(RecyclerView recyclerView, int dx, int dy) {                    super.onScrolled(recyclerView, dx, dy);                    totalItemCount = linearLayoutManager.getItemCount();                    lastVisibleItemPosition = linearLayoutManager.findLastVisibleItemPosition();                    Log.d("test", "totalItemCount =" + totalItemCount + "-----" + "lastVisibleItemPosition =" + lastVisibleItemPosition);                    if (!isLoading && totalItemCount <= (lastVisibleItemPosition + visibleThreshold)) {                        //此时是刷新状态                        if (mMoreDataListener != null)                            mMoreDataListener.loadMoreData();                        isLoading = true;                    }                }            });        }    }    public void setLoaded() {        isLoading = false;    }   @Override    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        RecyclerView.ViewHolder holder;        if (viewType == VIEW_ITEM) {            holder = new MyViewHolder(inflater.inflate(R.layout.item_view, parent, false));        } else {            holder = new MyProgressViewHolder(inflater.inflate(R.layout.item_footer, parent, false));        }        return holder;    }

@Override    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {        if (holder instanceof MyViewHolder) {            if (((MyViewHolder) holder).tv_name != null)                ((MyViewHolder) holder).tv_name.setText(mData.get(position));        } else if (holder instanceof MyProgressViewHolder) {            if (((MyProgressViewHolder) holder).pb != null)                ((MyProgressViewHolder) holder).pb.setIndeterminate(true);        }    }    @Override    public int getItemCount() {        return mData == null ? 0 : mData.size();    }    //依据不同的数据返回不同的viewType    @Override    public int getItemViewType(int position) {        return mData.get(position) != null ? VIEW_ITEM : VIEW_PROG;    }    public class MyViewHolder extends RecyclerView.ViewHolder {        private final TextView tv_name;        public MyViewHolder(View itemView) {            super(itemView);            tv_name = (TextView) itemView.findViewById(R.id.tv_name);            itemView.setOnClickListener(new View.OnClickListener() {                @Override                public void onClick(View v) {                    if (mOnitemClickListener != null)                        mOnitemClickListener.onClick(v);                }            });        }    }    public class MyProgressViewHolder extends RecyclerView.ViewHolder {        private final ProgressBar pb;        public MyProgressViewHolder(View itemView) {            super(itemView);            pb = (ProgressBar) itemView.findViewById(R.id.pb);        }    }    //设置数据的方法    public void setData(List
     
       data) {        mData = data;    }    private LoadMoreDataListener mMoreDataListener;    //载入很多其它监听方法    public void setOnMoreDataLoadListener(LoadMoreDataListener onMoreDataLoadListener) {        mMoreDataListener = onMoreDataLoadListener;    }    private RecyclerOnItemClickListener mOnitemClickListener;    //点击事件监听方法    public void setOnItemClickListener(RecyclerOnItemClickListener onItemClickListener) {        mOnitemClickListener = onItemClickListener;    }}

通过以上几部操作，就能够实现RecyclerView的底部载入很多其它的功能了，同一时候我用SwipeRefreshLayout实现了下拉刷新。

今天第一次写技术博客，应该有非常多地方写的不够妥当，望各位大神们指点。实现效果例如以下！

转载于:https://www.cnblogs.com/blfbuaa/p/7073467.html

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