RecyclerView替換ListView（包含SwipeRefreshLayout）

在android.support.v7包中，提供了一個新控件RecyclerView，是Android 5.0 materials design中的元件之一，用來替換ListView、GridView。本文主要講解RecycleView的基本用法，以及如何配合SwipeRefreshLayout實作下拉重新整理，上拉加載的功能。SwipeRefreshLayout是android.support.v4包中提供的。

一、RecyclerView的基本介紹

//設定擴充卡
m_recyclerView.setAdapter(m_adapter);
//設定布局方式
m_recyclerView.setLayoutManager(m_layoutManager);
//設定分割線
m_recyclerView.addItemDecoration(decoration);
//設定Item切換的動畫
m_recyclerView.setItemAnimator(new DefaultItemAnimator());

這是RecycleView使用的四個基本步驟，看起來是比ListView麻煩點，但是它的功能更加強大。

1、RecycleView.LayoutManager

LinearLayoutManager 相當于ListView；

GridLayoutManager 相當于GridView；

StaggeredGridLayoutManager 相當于瀑布流。

這三種LayoutManager都有含有orientation參數的構造方法，這個參數用來判斷RecycleView是豎直的還是水

平的。所有用RecycleView來實作水準的ListView和GridView更加友善。

2、RecycleView.ItemDecoration

相對于ListView設定分割線這方面而言，RecycleView沒有提供分割線，但是提供了ItemDecoration這個抽象

類給我們自定義分割線的樣式。

以下提供幾種分割線的實作方式：

（1）設定每個Item與周邊的邊距，RecycleView的父布局的顔色就成了分割線的顔色。（以上一種LayoutManager

通用）

public class SpacesItemDecoration extends RecyclerView.ItemDecoration {

    private int space;
    public SpacesItemDecoration(int space) {
        this.space = space;
    }

    /**
     * 設定每個Item與周邊的間距
     */
    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        outRect.left = space;
        outRect.right = space;
        outRect.bottom = space;
        if (parent.getChildAdapterPosition(view) == 0 || parent.getChildAdapterPosition(view) == 2 || parent.getChildAdapterPosition(view) == 1) {
            outRect.top = space;
        }
    }
}

（2）可以看到通過讀取系統主題中的 android.R.attr.listDivider作為Item間的分割線，并且支援橫向和縱向。以下是LinearLayoutManager作為LayoutManager時的方式。

public class DividerListItemDecoration 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 DividerListItemDecoration(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);
            android.support.v7.widget.RecyclerView v = new android.support.v7.widget.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);
        }
    }

}

（3）GridLayoutManager作為LayoutManager時，分割線的處理。

public class DividerGridItemDecoration extends RecyclerView.ItemDecoration
{

        private static final int[] ATTRS = new int[] { android.R.attr.listDivider };
        private Drawable mDivider;

        public DividerGridItemDecoration(Context context)
        {
            final TypedArray a = context.obtainStyledAttributes(ATTRS);
            mDivider = a.getDrawable(0);
            a.recycle();
        }

        @Override
        public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state)
        {

            drawHorizontal(c, parent);
            drawVertical(c, parent);

        }

        private int getSpanCount(RecyclerView parent)
        {
            // 列數
            int spanCount = -1;
            RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
            if (layoutManager instanceof GridLayoutManager)
            {

                spanCount = ((GridLayoutManager) layoutManager).getSpanCount();
            } else if (layoutManager instanceof StaggeredGridLayoutManager)
            {
                spanCount = ((StaggeredGridLayoutManager) layoutManager)
                        .getSpanCount();
            }
            return spanCount;
        }

        public void drawHorizontal(Canvas c, RecyclerView parent)
        {
            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.getLeft() - params.leftMargin;
                final int right = child.getRight() + params.rightMargin
                        + mDivider.getIntrinsicWidth();
                final int top = child.getBottom() + params.bottomMargin;
                final int bottom = top + mDivider.getIntrinsicHeight();
                mDivider.setBounds(left, top, right, bottom);
                mDivider.draw(c);
            }
        }

        public void drawVertical(Canvas c, RecyclerView parent)
        {
            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 top = child.getTop() - params.topMargin;
                final int bottom = child.getBottom() + params.bottomMargin;
                final int left = child.getRight() + params.rightMargin;
                final int right = left + mDivider.getIntrinsicWidth();

                mDivider.setBounds(left, top, right, bottom);
                mDivider.draw(c);
            }
        }

        private boolean isLastColum(RecyclerView parent, int pos, int spanCount,
                                    int childCount)
        {
            RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
            if (layoutManager instanceof GridLayoutManager)
            {
                if ((pos + 1) % spanCount == 0)// 如果是最後一列，則不需要繪制右邊
                {
                    return true;
                }
            } else if (layoutManager instanceof StaggeredGridLayoutManager)
            {
                int orientation = ((StaggeredGridLayoutManager) layoutManager)
                        .getOrientation();
                if (orientation == StaggeredGridLayoutManager.VERTICAL)
                {
                    if ((pos + 1) % spanCount == 0)// 如果是最後一列，則不需要繪制右邊
                    {
                        return true;
                    }
                } else
                {
                    childCount = childCount - childCount % spanCount;
                    if (pos >= childCount)// 如果是最後一列，則不需要繪制右邊
                        return true;
                }
            }
            return false;
        }

        private boolean isLastRaw(RecyclerView parent, int pos, int spanCount,
                                  int childCount)
        {
            RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
            if (layoutManager instanceof GridLayoutManager)
            {
                childCount = childCount - childCount % spanCount;
                if (pos >= childCount)// 如果是最後一行，則不需要繪制底部
                    return true;
            } else if (layoutManager instanceof StaggeredGridLayoutManager)
            {
                int orientation = ((StaggeredGridLayoutManager) layoutManager)
                        .getOrientation();
                // StaggeredGridLayoutManager 且縱向滾動
                if (orientation == StaggeredGridLayoutManager.VERTICAL)
                {
                    childCount = childCount - childCount % spanCount;
                    // 如果是最後一行，則不需要繪制底部
                    if (pos >= childCount)
                        return true;
                } else
                // StaggeredGridLayoutManager 且橫向滾動
                {
                    // 如果是最後一行，則不需要繪制底部
                    if ((pos + 1) % spanCount == 0)
                    {
                        return true;
                    }
                }
            }
            return false;
        }

        @Override
        public void getItemOffsets(Rect outRect, int itemPosition,
                                   RecyclerView parent)
        {
            int spanCount = getSpanCount(parent);
            int childCount = parent.getAdapter().getItemCount();
            if (isLastRaw(parent, itemPosition, spanCount, childCount))// 如果是最後一行，則不需要繪制底部
            {
                outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
            } else if (isLastColum(parent, itemPosition, spanCount, childCount))// 如果是最後一列，則不需要繪制右邊
            {
                outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
            } else
            {
                outRect.set(0, 0, mDivider.getIntrinsicWidth(),
                        mDivider.getIntrinsicHeight());
            }
        }

}

參考http://blog.csdn.net/lmj623565791/article/details/45059587

3、RecycleView.ItemAnimator

這也是個抽象類，用來處理RecycleView的Item删除和插入時的動畫，不過SDK給我們提供了一個預設的實作類DefaultItemAnimator。

4、到了RecycleView四個步驟中最重要的一步了，setAdapter。與ListView和GridView一樣，也需要設定擴充卡，不過這裡并不是繼承BaseAdapter了，而是RecycleView.Adapter。之前ListView的擴充卡中ViewHolder的使用不是強制性的，在RecycleView中已經是必須得寫的了。

public class MyRecyclerAdapter extends RecyclerView.Adapter<MyRecyclerAdapter.MyViewHolder> {
    private Context context;

    public MyRecyclerAdapter(List<String> list, Context context) {
        this.context = context;
    }

    @Override
    public MyRecyclerAdapter.MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(context).inflate(R.layout.content_main, null);
        MyViewHolder myViewHolder = new MyViewHolder(view);
        return myViewHolder;
    }

    @Override
    public void onBindViewHolder(final MyRecyclerAdapter.MyViewHolder holder, final int position) {
        holder.textView.setText("第"+position+"個Item");
    }

    @Override
    public int getItemCount() {
        return 30;
    }

    class MyViewHolder extends RecyclerView.ViewHolder {
        TextView textView;
        CardView cardView;

        public MyViewHolder(View itemView) {
            super(itemView);
            textView = (TextView) itemView.findViewById(R.id.textView);
        }
    }
}

重寫這個擴充卡，主要實作三個方法、寫一個ViewHolder。

（1）onCreateViewHolder 建立ViewHolder

（2）onBindViewHolder 将ViewHolder與資料源綁定

（3）getItemCount Item的總是

實作以上四步，RecycleView的基本使用就掌握了，效果圖如下：

RecyclerView替換ListView（包含SwipeRefreshLayout）

二、RecycleView功能進階。

1、點選事件、長按事件

RecycleView沒有提供OnClickListener和OnLongClickListener，需要我們自己實作。

在自定義的Adapter中定義一個接口，代碼如下：

private OnItemClickListener onItemClickListener;
public interface OnItemClickListener {
    void OnItemClick(View view, int position);

    void OnItemLongClick(View view, int position);
}

public void setOnItemClickListener(OnItemClickListener onItemClickListener) {
    this.onItemClickListener = onItemClickListener;
}

在onBindViewHolder方法中調用接口中的方法

if (onItemClickListener != null) {
    holder.textView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            int pos = holder.getLayoutPosition();
            onItemClickListener.OnItemClick((((MyViewHolder) holder).textView), pos);
        }
    });
    holder.textView.setOnLongClickListener(new View.OnLongClickListener() {
        @Override
        public boolean onLongClick(View v) {
            int pos = holder.getLayoutPosition();
            onItemClickListener.OnItemLongClick((((MyViewHolder) holder).textView), pos);
            return false;
        }
    });
}

在MainActivity中使用時，直接調用Adapter中的方法，實作這個接口。

m_adapter.setOnItemClickListener(new MyRecyclerAdapter.OnItemClickListener() {
    @Override
    public void OnItemClick(View view, int position) {
        Toast.makeText(MainActivity.this, "點選了" + position, Toast.LENGTH_SHORT).show();
    }

    @Override
    public void OnItemLongClick(View view, int position) {
       Toast.makeText(MainActivity.this, "長按了" + position, Toast.LENGTH_SHORT).show();              
 }});

2、删除與插入

在自定義的Adapter中定義兩個方法，如下：

public void addItem(int position) {
    m_listData.add(position, "Insert One");
    notifyItemInserted(position);
}

public void deleteItem(int position) {
    m_listData.remove(position);
    notifyItemRemoved(position);
}

重新整理擴充卡的方法調用上面notifyItemInserted(position)和notifyItemRemoved(position)，這樣才能執行之前設定的Item的Animation

三、RecycleView與SwipeRefreshLayout配合實作下拉重新整理、加載更多。

1、下拉重新整理

<android.support.v4.widget.SwipeRefreshLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/swipe_refresh_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</android.support.v4.widget.SwipeRefreshLayout>

//設定下拉重新整理進度條的顔色
m_swipeRefreshLayout.setColorSchemeResources(android.R.color.holo_blue_light,
        android.R.color.holo_red_light, android.R.color.holo_orange_light,
        android.R.color.holo_green_light);

m_swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
    @Override
    public void onRefresh() {
        m_swipeRefreshLayout.postDelayed(new Runnable() {
            @Override
            public void run() {
                m_swipeRefreshLayout.setRefreshing(false);
                m_adapter.addItem(1);
            }
        }, 1000);
    }
});

直接這樣使用，RecycleView的滾動和SwipeRefreshLayout的下拉沖突，造成每次下拉都會觸發onRefreshListener。需要判斷，隻有當RecycleView滾動到頂部時，下拉才觸發重新整理的事件。

//通過對RecycleView的滾動狀态進行監聽，當第0個位置的Item的頂部的坐标大于或等于0時，将SwipeRefreshView設定成可以重新整理的，反之設定成不可重新整理的
m_recyclerView.setOnScrollListener(new RecyclerView.OnScrollListener() {
    @Override
    public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
        super.onScrollStateChanged(recyclerView, newState);
        //設定下拉重新整理的事件
        int topRowVerticalPosition = (recyclerView == null || recyclerView.getChildCount() == 0) ? 0 : recyclerView.getChildAt(0).getTop();
        m_swipeRefreshLayout.setEnabled(topRowVerticalPosition >= 0);
    }

    @Override
    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
        super.onScrolled(recyclerView, dx, dy);
    }
});

在OnScrollStateChanged中的那兩句代碼寫的很好，判斷當RecycleView的第一個Item的頂部的坐标等于0時将SwipeRefreshLayout設定成Enabled，反之不觸發滾動事件。

2、加載更多

在ListView中有addFootView方法，RecycleView沒有，是以需要我們自己判斷。

在Adapter中有getItemViewType(position)方法，可以判斷每個Item的類型。

@Override
public int getItemViewType(int position) {
    if (position + 1 == getItemCount()) {
        return TYPE_FOOTER;
    } else {
        return TYPE_ITEM;
    }
}

完整的Adapter類如下：

package com.example.newviewuser;

import android.content.Context;
import android.support.v7.widget.CardView;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

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

/**
 * Created by Administrator on 2016/1/25.
 */
public class MyRecyclerAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
    private Random random = new Random();
    private List<String> m_listData;
    private Context context;
    private List<Integer> mHeights;
    private static final int GENERAL_VIEW = 0;  //普通Item
    private static final int FOOTER_VIEW = 1;  //最底部的Item
    //上拉加載更多
    public static final int  PULLUP_LOAD_MORE=0;
    //正在加載中
    public static final int  LOADING_MORE=1;
    //上拉加載更多狀态-預設為0
    private int load_more_status=0;

    private OnItemClickListener onItemClickListener;
    public interface OnItemClickListener {
        void OnItemClick(View view, int position);

        void OnItemLongClick(View view, int position);
    }

    public void setOnItemClickListener(OnItemClickListener onItemClickListener) {
        this.onItemClickListener = onItemClickListener;
    }

    public MyRecyclerAdapter(List<String> list, Context context) {
        m_listData = list;
        this.context = context;
        mHeights = new ArrayList<Integer>();
        for (int i = 0; i < m_listData.size(); i++) {
            mHeights.add((int) (100 + Math.random() * 300));
        }
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        if (viewType == GENERAL_VIEW) {
            View view = LayoutInflater.from(context).inflate(R.layout.content_main, null);
            MyViewHolder myViewHolder = new MyViewHolder(view);
            return myViewHolder;
        } else if (viewType == FOOTER_VIEW) {
            View view = LayoutInflater.from(context).inflate(R.layout.footer_layout, null);
            FootViewHolder footViewHolder = new FootViewHolder(view);
            return footViewHolder;
        }
        return null;
    }

    @Override
    public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int position) {
        if (holder instanceof MyViewHolder) {
            (((MyViewHolder) holder).textView).setText("第"+position+"個Item");
            if (onItemClickListener != null) {
                (((MyViewHolder) holder).textView).setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        int pos = holder.getLayoutPosition();
                        onItemClickListener.OnItemClick((((MyViewHolder) holder).textView), pos);
                    }
                });
                (((MyViewHolder) holder).textView).setOnLongClickListener(new View.OnLongClickListener() {
                    @Override
                    public boolean onLongClick(View v) {
                        int pos = holder.getLayoutPosition();
                        onItemClickListener.OnItemLongClick((((MyViewHolder) holder).textView), pos);
                        return false;
                    }
                });
            }
        }else if (holder instanceof FootViewHolder){
            FootViewHolder footViewHolder = (FootViewHolder) holder;
            switch (load_more_status){
                case PULLUP_LOAD_MORE:
                    footViewHolder.textView.setText("上拉加載更多...");
                    break;
                case LOADING_MORE:
                    footViewHolder.textView.setText("正在加載更多資料...");
                    break;
            }
        }
    }

    @Override
    public int getItemCount() {
        return m_listData.size() + 1;
    }

    @Override
    public int getItemViewType(int position) {
        if (position + 1 == getItemCount()) {
            return FOOTER_VIEW;
        } else {
            return GENERAL_VIEW;
        }
    }

    public void addItem(int position) {
        m_listData.add(position, "Insert One");
        if (mHeights.size() < m_listData.size()) {
            mHeights.add((int) (100 + Math.random() * 300));
        }
        notifyItemInserted(position);
    }

    public void deleteItem(int position) {
        m_listData.remove(position);
        notifyItemRemoved(position);
    }

    public void addMoreItem(List<String> newDatas) {
        m_listData.addAll(newDatas);
        notifyDataSetChanged();
    }

    /**
     * //上拉加載更多
     * PULLUP_LOAD_MORE=0;
     *  //正在加載中
     * LOADING_MORE=1;
     * //加載完成已經沒有更多資料了
     * NO_MORE_DATA=2;
     * @param status
     */
    public void changeMoreStatus(int status){
        load_more_status=status;
        notifyDataSetChanged();
    }

    class MyViewHolder extends RecyclerView.ViewHolder {
        TextView textView;
        CardView cardView;

        public MyViewHolder(View itemView) {
            super(itemView);
            textView = (TextView) itemView.findViewById(R.id.textView);
        }
    }

    class FootViewHolder extends RecyclerView.ViewHolder {
        TextView textView;

        public FootViewHolder(View itemView) {
            super(itemView);
            textView = (TextView) itemView.findViewById(R.id.text_view_footer);
        }
    }
}

在RecycleView滾動的監聽中判斷，當滾動底部時，顯示加載更多的布局，改變FootView的狀态。

m_recyclerView.setOnScrollListener(new RecyclerView.OnScrollListener() {
    @Override
    public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
        super.onScrollStateChanged(recyclerView, newState);
        //設定下拉重新整理的時間
        int topRowVerticalPosition = (recyclerView == null || recyclerView.getChildCount() == 0) ? 0 : recyclerView.getChildAt(0).getTop();
        m_swipeRefreshLayout.setEnabled(topRowVerticalPosition >= 0);
        if (newState == RecyclerView.SCROLL_STATE_IDLE && lastVisibleItem +1 == m_adapter.getItemCount()) {
            m_adapter.changeMoreStatus(MyRecyclerAdapter.LOADING_MORE);
            new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {
                    List<String> addString = new ArrayList<String>();
                    addString.add("加載更多增加的資料");
                    m_adapter.addMoreItem(addString);
                    m_adapter.changeMoreStatus(MyRecyclerAdapter.PULLUP_LOAD_MORE);
                    m_adapter.notifyDataSetChanged();
                }
            },2500);
        }
    }

    @Override
    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
        super.onScrolled(recyclerView, dx, dy);
        lastVisibleItem = m_layoutManager.findLastVisibleItemPosition();
    }
});

下載下傳源碼

RecyclerView替換ListView（包含SwipeRefreshLayout）

繼續閱讀

專訪鄧凡平：深入了解Android

與專家面對面：Android開發入門問與答

Android MVP架構MVCMVP

mvp初探

Android常用工具類簡介目錄

android常用工具類轉載自：http://www.trinea.cn/android/android-common-utils/Android常用工具類

Android常用工具類ToastUtilsSizeUtilsLogUtilsRetrofitManagerAnimUtil

Android Studio 0.8.0解決 Failure [INSTALL_FAILED_OLDER_SDK] 問題

Android – ListView 中添加按鈕，動态删除添加ItemView的操作

Kotlin的ListView與RecyclerView的簡單應用

關于公司的那些坑：Android Studio篇

android SQLite事務和kotlin協程

無法正常編譯錯誤Compilation failed to complete

關于Gradle配置的小結

AOP程式設計_Android優雅權限架構(1)概念基礎，2021金三銀四前言正文大綱正文

Android APK檔案反編譯Android APK檔案反編譯