Android开发之RecyclerView的上拉刷新和下拉加载

自2015年谷歌开发者大会的召开后，给我们推出了一个新的控件即RecyclerView，它将逐步取代ListView和GriView，对于一些资讯类新闻类的App而言，下拉刷新上拉加载都是不可缺少的功能，那么RecyclerView如何实现上拉刷新和下拉加载呢，经过本人一段时间的研究，终于实现了，下面将代码贴出，还望诸位大神批评指正，灰常感谢♪(^∇^*)

特别注意：

由于本人的Demo中集成了DATABINDINGLIBRARY,即数据绑定库，故使用AS开发的话，需要配置这两步：

1.在项目的build.gradle（非module）中的dependencies下添加配置

classpath "com.android.databinding:dataBinder:1.0-rc1"

2.在module的build.gradle中的添加配置

apply plugin: 'com.android.databinding'

效果图如下：

核心代码如下：

MainActivity

package com.hxht.testrecyclerviewloadmore;import android.databinding.DataBindingUtil;import android.graphics.Color;import android.os.Bundle;import android.os.Handler;import android.support.v4.widget.SwipeRefreshLayout;import android.support.v7.app.AppCompatActivity;import android.support.v7.widget.LinearLayoutManager;import android.support.v7.widget.RecyclerView;import android.view.View;import android.widget.Toast;import com.hxht.testrecyclerviewloadmore.adapter.MyRecyclerViewAdapter;import com.hxht.testrecyclerviewloadmore.callback.OnRcvScrollListener;import com.hxht.testrecyclerviewloadmore.databinding.ActivityMainBinding;import com.hxht.testrecyclerviewloadmore.domain.HelpClass;import java.util.ArrayList;import java.util.List;public class MainActivity extends AppCompatActivity {    private ActivityMainBinding binding;    private List<String> list;    private int index = 1;    private int page = 1;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        initView();        initData();    }    private void initView() {        binding = DataBindingUtil.setContentView(this, R.layout.activity_main);    }    private void initData() {        HelpClass helpClass = new HelpClass("正在加载、、、");        binding.setHelpclass(helpClass);        list = new ArrayList<>();        list.clear();        for (int i = 1; i < 201; i++) {            list.add("测试" + (i < 10 ? "0" + i : i));        }        final MyRecyclerViewAdapter adapter = new MyRecyclerViewAdapter(MainActivity.this, list);        RecyclerView.LayoutManager manager = new LinearLayoutManager(MainActivity.this, LinearLayoutManager.VERTICAL, false);        binding.recycleview.setAdapter(adapter);        binding.recycleview.setLayoutManager(manager);        binding.recycleview.addItemDecoration(new DividerItemDecoration(MainActivity.this, DividerItemDecoration.VERTICAL_LIST));        int[] colos = new int[]{                Color.RED,                Color.YELLOW,                Color.GREEN,                Color.BLUE,                Color.BLACK        };        binding.swiperefreshlayout.setColorSchemeColors(colos);        binding.swiperefreshlayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {            @Override            public void onRefresh() {                Handler handler = new Handler();                handler.postDelayed(new Runnable() {                    @Override                    public void run() {                        list.clear();                        int count = index++;                        for (int i = 1; i < 201; i++) {                            list.add("第" + count + "次刷新---item" + (i < 10 ? "0" + i : i));                        }                        adapter.notifyDataSetChanged();                        binding.swiperefreshlayout.setRefreshing(false);                    }                }, 5000);            }        });        binding.recycleview.setOnScrollListener(new OnRcvScrollListener() {            @Override            public void onBottom() {                super.onBottom();                Handler handler = new Handler();                binding.tvLoadMore.setVisibility(View.VISIBLE);                handler.postDelayed(new Runnable() {                    @Override                    public void run() {                        int currentPage = page++;                        int position = list.size() ;                        for (int i = 1; i < 201; i++) {                            list.add("加载出第" + currentPage + "页的数据" + (i < 10 ? "0" + i : i));                        }                        adapter.notifyDataSetChanged();                        binding.tvLoadMore.setVisibility(View.GONE);                        binding.recycleview.smoothScrollToPosition(position);                    }                }, 3000);            }        });    }}

MyRecyclerViewAdapter

package com.hxht.testrecyclerviewloadmore.adapter;import android.content.Context;import android.support.v7.widget.RecyclerView;import android.view.View;import android.view.ViewGroup;import android.widget.TextView;import com.hxht.testrecyclerviewloadmore.R;import java.util.List;public class MyRecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewAdapter.MyViewHolder> {    private Context mContext;    private List<String> list;    public MyRecyclerViewAdapter(Context mContext, List<String> list) {        this.mContext = mContext;        this.list = list;    }    private interface OnItemClickListener {        void onItemClick(View view, int position);    }    private OnItemClickListener mOnItemClickListener;    public OnItemClickListener getmOnItemClickListener() {        return mOnItemClickListener;    }    public void setmOnItemClickListener(OnItemClickListener mOnItemClickListener) {        this.mOnItemClickListener = mOnItemClickListener;    }    @Override    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        View view = View.inflate(mContext, R.layout.activity_rv_item, null);        return new MyViewHolder(view);    }    @Override    public void onBindViewHolder(MyViewHolder holder, final int position) {        holder.tv.setText(list.get(position));        holder.view.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                if (mOnItemClickListener != null) {                    mOnItemClickListener.onItemClick(v, position);                }            }        });    }    @Override    public int getItemCount() {        return list.size();    }    class MyViewHolder extends RecyclerView.ViewHolder {        private View view;        private TextView tv;        public MyViewHolder(View itemView) {            super(itemView);            this.view = itemView;            this.tv = (TextView) view.findViewById(R.id.tv);        }    }}

OnBottomListener

package com.hxht.testrecyclerviewloadmore.callback;public interface OnBottomListener {    void onBottom();}

OnRecyclerViewScrollListener

package com.hxht.testrecyclerviewloadmore.callback;import android.support.v7.widget.GridLayoutManager;import android.support.v7.widget.LinearLayoutManager;import android.support.v7.widget.RecyclerView;import android.support.v7.widget.StaggeredGridLayoutManager;public class OnRecyclerViewScrollListener extends RecyclerView.OnScrollListener implements OnBottomListener {    private String TAG = getClass().getSimpleName();    public static enum LAYOUT_MANAGER_TYPE {        LINEAR,        GRID,        STAGGERED_GRID    }    protected LAYOUT_MANAGER_TYPE layoutManagerType;    private int[] lastPositions;    private int lastVisibleItemPosition;    private int currentScrollState = 0;    @Override    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {        super.onScrolled(recyclerView, dx, dy);        RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();        //  int lastVisibleItemPosition = -1;        if (layoutManagerType == null) {            if (layoutManager instanceof LinearLayoutManager) {                layoutManagerType = LAYOUT_MANAGER_TYPE.LINEAR;            } else if (layoutManager instanceof GridLayoutManager) {                layoutManagerType = LAYOUT_MANAGER_TYPE.GRID;            } else if (layoutManager instanceof StaggeredGridLayoutManager) {                layoutManagerType = LAYOUT_MANAGER_TYPE.STAGGERED_GRID;            } else {                throw new RuntimeException(                        "Unsupported LayoutManager used. Valid ones are LinearLayoutManager, GridLayoutManager and StaggeredGridLayoutManager");            }        }        switch (layoutManagerType) {            case LINEAR:                lastVisibleItemPosition = ((LinearLayoutManager) layoutManager)                        .findLastVisibleItemPosition();                break;            case GRID:                lastVisibleItemPosition = ((GridLayoutManager) layoutManager)                        .findLastVisibleItemPosition();                break;            case STAGGERED_GRID:                StaggeredGridLayoutManager staggeredGridLayoutManager                        = (StaggeredGridLayoutManager) layoutManager;                if (lastPositions == null) {                    lastPositions = new int[staggeredGridLayoutManager.getSpanCount()];                }                staggeredGridLayoutManager.findLastVisibleItemPositions(lastPositions);                lastVisibleItemPosition = findMax(lastPositions);                break;        }    }    @Override    public void onScrollStateChanged(RecyclerView recyclerView, int newState) {        super.onScrollStateChanged(recyclerView, newState);        currentScrollState = newState;        RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();        int visibleItemCount = layoutManager.getChildCount();        int totalItemCount = layoutManager.getItemCount();        if ((visibleItemCount > 0 && currentScrollState == RecyclerView.SCROLL_STATE_IDLE &&                (lastVisibleItemPosition) >= totalItemCount - 1)) {            onBottom();        }    }    @Override    public void onBottom() {}    private int findMax(int[] lastPositions) {        int max = lastPositions[0];        for (int value : lastPositions) {            if (value > max) {                max = value;            }        }        return max;    }}

DividerItemDecoration

package com.hxht.testrecyclerviewloadmore;import android.content.Context;import android.content.res.TypedArray;import android.graphics.Canvas;import android.graphics.Rect;import android.graphics.drawable.Drawable;import android.support.v7.widget.LinearLayoutManager;import android.support.v7.widget.RecyclerView;import android.view.View;public class DividerItemDecoration extends RecyclerView.ItemDecoration {    private static final int[] ATTRS = new int[]{            android.R.attr.listDivider    };    public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;    public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;    private Drawable mDivider;    private int mOrientation;    public DividerItemDecoration(Context context, int orientation) {        final TypedArray a = context.obtainStyledAttributes(ATTRS);        mDivider = a.getDrawable(0);        a.recycle();        setOrientation(orientation);    }    public void setOrientation(int orientation) {        if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) {            throw new IllegalArgumentException("invalid orientation");        }        mOrientation = orientation;    }    @Override    public void onDraw(Canvas c, RecyclerView parent) {        if (mOrientation == VERTICAL_LIST) {            drawVertical(c, parent);        } else {            drawHorizontal(c, parent);        }    }    public void drawVertical(Canvas c, RecyclerView parent) {        final int left = parent.getPaddingLeft();        final int right = parent.getWidth() - parent.getPaddingRight();        final int childCount = parent.getChildCount();        for (int i = 0; i < childCount; i++) {            final View child = parent.getChildAt(i);            RecyclerView v = new RecyclerView(parent.getContext());            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child                    .getLayoutParams();            final int top = child.getBottom() + params.bottomMargin;            final int bottom = top + mDivider.getIntrinsicHeight();            mDivider.setBounds(left, top, right, bottom);            mDivider.draw(c);        }    }    public void drawHorizontal(Canvas c, RecyclerView parent) {        final int top = parent.getPaddingTop();        final int bottom = parent.getHeight() - parent.getPaddingBottom();        final int childCount = parent.getChildCount();        for (int i = 0; i < childCount; i++) {            final View child = parent.getChildAt(i);            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child                    .getLayoutParams();            final int left = child.getRight() + params.rightMargin;            final int right = left + mDivider.getIntrinsicHeight();            mDivider.setBounds(left, top, right, bottom);            mDivider.draw(c);        }    }    @Override    public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {        if (mOrientation == VERTICAL_LIST) {            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());        } else {            outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);        }    }}

HelpClass

package com.hxht.testrecyclerviewloadmore.domain;public class HelpClass {    private String tv_name ;    public HelpClass(String tv_name) {        this.tv_name = tv_name;    }    public String getTv_name() {        return tv_name;    }    public void setTv_name(String tv_name) {        this.tv_name = tv_name;    }    @Override    public String toString() {        return "HelpClass{" +                "tv_name='" + tv_name + '\'' +                '}';    }}

代码已贴出，正所谓取之于社会，回报于社会，还望诸位大神批评指正，不喜勿喷，灰常感谢♪(^∇^*)