万能的 RecyclerViewAdapter，支持上拉加载、添加 HeadView

最近的项目，使用RecyclerView比较多，导致需要写大量的Adapter和ViewHolder。不想偷懒的程序员不是好程序员。于是，查了一些资料，对RecyclerView的Adapter进行了一些封装。使用的时候减少了大量的工作。

先来点效果图

1.gif

2.gif

封装后的Adapter使用：

class DragSwipeAdapter extends BaseAdapter {
       public DragSwipeAdapter(Context mContext, List mDatas, int mLayoutId) {
           super(mContext, mDatas, mLayoutId);
       }

       @Override
       protected void convert(Context mContext, BaseViewHolder holder, String s) {
            holder.setText(R.id.tv,s);
       }
   }

只要传入数据源和item布局即可，是不是超级简单。

下面看看怎么实现的吧。

通用ViewHolder

package org.raphets.demorecyclerview.adapter;
import android.annotation.SuppressLint;
import android.graphics.Bitmap;
import android.graphics.drawable.Drawable;
import android.os.Build;
import android.support.v7.widget.RecyclerView;
import android.text.SpannableStringBuilder;
import android.util.SparseArray;
import android.view.View;
import android.view.animation.AlphaAnimation;
import android.widget.Checkable;
import android.widget.ImageView;
import android.widget.TextView;

public class BaseViewHolder extends RecyclerView.ViewHolder {
    SparseArray mViews;
    View mItemView;

    public BaseViewHolder(View itemView) {
        super(itemView);
        mItemView = itemView;
        mViews = new SparseArray<>();
    }
    public  T getView(int viewId) {
        View view = mViews.get(viewId);
        if (view == null) {
            view = mItemView.findViewById(viewId);
            mViews.put(viewId, view);
        }
        return (T) view;
    }
    public BaseViewHolder setText(int viewId, int resId) {
        TextView textView = getView(viewId);
        textView.setText(resId);
        return this;
    }
    public BaseViewHolder setText(int viewId, String text) {
        TextView textView = getView(viewId);
        textView.setText(text);
        return this;
    }
    public BaseViewHolder setText(int viewId, SpannableStringBuilder text) {
        TextView textView = getView(viewId);
        textView.setText(text);
        return this;
    }
    public BaseViewHolder setImageResource(int viewId, int resId) {
        ImageView view = getView(viewId);
        view.setImageResource(resId);
        return this;
    }
    public BaseViewHolder setImageBitmap(int viewId, Bitmap bitmap) {
        ImageView view = getView(viewId);
        view.setImageBitmap(bitmap);
        return this;
    }
    public BaseViewHolder setImageDrawable(int viewId, Drawable drawable) {
        ImageView view = getView(viewId);
        view.setImageDrawable(drawable);
        return this;
    }
    public BaseViewHolder setBackgroundColor(int viewId, int color) {
        View view = getView(viewId);
        view.setBackgroundColor(color);
        return this;
    }
    public BaseViewHolder setBackgroundResource(int viewId, int backgroundRes) {
        View view = getView(viewId);
        view.setBackgroundResource(backgroundRes);
        return this;
    }
    public BaseViewHolder setTextColor(int viewId, int textColor) {
        TextView view = getView(viewId);
        view.setTextColor(textColor);
        return this;
    }
    @SuppressLint("NewApi")
    public BaseViewHolder setAlpha(int viewId, float value) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
            getView(viewId).setAlpha(value);
        } else {
            // Pre-honeycomb hack to set Alpha value
            AlphaAnimation alpha = new AlphaAnimation(value, value);
            alpha.setDuration(0);
            alpha.setFillAfter(true);
            getView(viewId).startAnimation(alpha);
        }
        return this;
    }
    public BaseViewHolder setVisible(int viewId, boolean visible) {
        View view = getView(viewId);
        view.setVisibility(visible ? View.VISIBLE : View.GONE);
        return this;
    }
    public BaseViewHolder setTag(int viewId, Object tag) {
        View view = getView(viewId);
        view.setTag(tag);
        return this;
    }
    public BaseViewHolder setTag(int viewId, int key, Object tag) {
        View view = getView(viewId);
        view.setTag(key, tag);
        return this;
    }
    public BaseViewHolder setChecked(int viewId, boolean checked) {
        Checkable view = (Checkable) getView(viewId);
        view.setChecked(checked);
        return this;
    }
    /**
     * 关于事件监听
     */
    public BaseViewHolder setOnClickListener(int viewId, View.OnClickListener listener) {

        View view = getView(viewId);
        view.setOnClickListener(listener);
        return this;
    }
    public BaseViewHolder setOnTouchListener(int viewId, View.OnTouchListener listener) {
        View view = getView(viewId);
        view.setOnTouchListener(listener);
        return this;
    }
    public BaseViewHolder setOnLongClickListener(int viewId, View.OnLongClickListener listener) {
        View view = getView(viewId);
        view.setOnLongClickListener(listener);
        return this;
    }
}

这里对TextView、ImageView等常用控件的一些常用方法进行了封装。有了这个通用ViewHolder，再多的Adapter也只需要这一个ViewHolder，不用每写一个Adapter就要写一个ViewHolder。

通用Adapter

package org.raphets.demorecyclerview.adapter;
import android.content.Context;
import android.support.v7.util.DiffUtil;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import java.util.List;
/**
 * Created by RaphetS on 2016/9/28.
 * 普通的万能Adapter
 * 支持onItemClick
 * 支持onLongItemClick
 */
public abstract class BaseAdapter extends RecyclerView.Adapter {
    private Context mContext;
    private List mDatas;
    private int mLayoutId;
    private OnItemClickListener mItemClickListener;
    private onLongItemClickListener mLongItemClickListener;

    public BaseAdapter(Context mContext, List mDatas, int mLayoutId) {
        this.mContext = mContext;
        this.mDatas = mDatas;
        this.mLayoutId = mLayoutId;
    }

    public void updateData(List data) {
        mDatas.clear();
        mDatas.addAll(data);
        notifyDataSetChanged();
    }

    public void addAll(List data) {
        mDatas.addAll(data);
        notifyDataSetChanged();
    }

    @Override
    public BaseViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(mContext).inflate(mLayoutId, parent, false);
        BaseViewHolder holder = new BaseViewHolder(view);
        return holder;
    }

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

    @Override
    public void onBindViewHolder(BaseViewHolder holder, final int position) {
        convert(mContext, holder, mDatas.get(position));
        if (mItemClickListener != null) {
            holder.mItemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    mItemClickListener.onItemClick(v, position);
                }
            });
        }
        if (mLongItemClickListener != null) {
            holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
                @Override
                public boolean onLongClick(View v) {
                    mLongItemClickListener.onLongItemClick(v, position);
                    return true;
                }
            });
        }
    }

    protected abstract void convert(Context mContext, BaseViewHolder holder, T t);

    public    interface OnItemClickListener {
        void onItemClick(View view, int position);
    }

    public    interface onLongItemClickListener {
        void onLongItemClick(View view, int postion);
    }

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

    public void setonLongItemClickListener(onLongItemClickListener listener) {
        this.mLongItemClickListener = listener;
    }
}

这里对RecyclerViewAdapter通用的地方封装了一下，然后封装了一下onItemClick和onLongItemClick事件。

如何使用

首先，写一个Adapter继承通用Adapter

class DragSwipeAdapter extends BaseAdapter {
       public DragSwipeAdapter(Context mContext, List mDatas, int mLayoutId) {
           super(mContext, mDatas, mLayoutId);
       }

       @Override
       protected void convert(Context mContext, BaseViewHolder holder, String s) {
            holder.setText(R.id.tv,s)
            .setTextColor(R.id.tv, Color.RED)
            .setImageResource(R.id.imageView,R.mipmap.ic_launcher);
           ImageView imageView=holder.getView(R.id.imageView); 
           imageView.setImageResource(R.mipmap.ic_launcher);
       }
   }

代码比起原生的是不是少很多？

然后在Activity中使用即可。只要传入Context，数据源，item布局即可。

 mAdapter = new DragSwipeAdapter(this, mData, R.layout.item);
 mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
 mRecyclerView.setAdapter(mAdapter);

是不是少了大量的工作。

但是貌似封装的还不够，我们的RecyclerView经常需要使用的功能还有下拉刷新，上拉加载，加个headview等等。下拉刷新好说，直接使用v4包里的SwipeRefreshLayout即可，上拉加载和HeadView怎么办呢？

下面我对上拉加载和HeadView也进行了一下封装。

（目前只支持LinearLayoutManager布局的RecyclerView）

• 首先ViewHoder不变，依然是上面的ViewHolder。

• 然后写了一个底部加载中的一个item布局。

• 下面是封装的Adapter

package org.raphets.demorecyclerview.adapter;
import android.content.Context;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import org.raphets.demorecyclerview.R;
import java.util.List;
/**
 * Created by RaphetS on 2016/10/1.
 *  支持上拉加载
 *  支持添加HeadView
 *  底部有进度条
 */
public abstract class BaseLoadMoreHeaderAdapter extends RecyclerView.Adapter {
    private Context mContext;
    private boolean isLoading=false;
    private OnLoadMoreListener mOnLoadMoreListener;
    private OnItemClickListener mItemClickListener;
    private onLongItemClickListener mLongItemClickListener;
    private List mDatas;
    private int mLayoutId;
    private View mHeadView;
    private final static int TYPE_HEADVIEW=100;
    private final static int TYPE_ITEM=101;
    private final static int TYPE_PROGRESS=102;

    public BaseLoadMoreHeaderAdapter(Context mContext, RecyclerView recyclerView, List mDatas, int mLayoutId) {
        this.mContext = mContext;
        this.mDatas = mDatas;
        this.mLayoutId = mLayoutId;
        init(recyclerView);
    }
    private void init(RecyclerView recyclerView) {
        //mRecyclerView添加滑动事件监听
        recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                LinearLayoutManager linearLayoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();
                int    totalItemCount = linearLayoutManager.getItemCount();
                int    lastVisibleItemPosition = linearLayoutManager.findLastVisibleItemPosition();
                if (!isLoading &&dy>0&&lastVisibleItemPosition>=totalItemCount-1) {
                    //此时是刷新状态
                    if (mOnLoadMoreListener != null) {
                        mOnLoadMoreListener.onLoadMore();
                    }
                    isLoading = true;
                }
            }
        });
    }
    public void updateData(List data) {
        mDatas.clear();
        mDatas.addAll(data);
        notifyDataSetChanged();
    }

    public void addAll(List data) {
        mDatas.addAll(data);
        notifyDataSetChanged();
    }
    public void addHeadView(View headView){
        mHeadView=headView;
    }
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        if (viewType==TYPE_ITEM){
            View itemView= LayoutInflater.from(mContext).inflate(mLayoutId,parent,false);
            BaseViewHolder baseViewHolder=new BaseViewHolder(itemView);
            return baseViewHolder;
        }else if (viewType==TYPE_HEADVIEW){
            HeadViewHolder headViewHolder=new HeadViewHolder(mHeadView);
            return headViewHolder;
        } else{
            View progressView=LayoutInflater.from(mContext).inflate(R.layout.progress_item,parent,false);
            ProgressViewHolder progressViewHolder= new ProgressViewHolder(progressView);
            return progressViewHolder;
        }
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, final int position) {
      if (holder instanceof BaseViewHolder){
          convert(mContext, holder, mDatas.get(position));
          ((BaseViewHolder) holder).mItemView.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View v) {
                  mItemClickListener.onItemClick(v,position-1);
              }
          });
          ((BaseViewHolder) holder).mItemView.setOnLongClickListener(new View.OnLongClickListener() {
              @Override
              public boolean onLongClick(View v) {
                  mLongItemClickListener.onLongItemClick(v,position-1);
                  return true;
              }
          });
      }
    }

    @Override
    public int getItemViewType(int position) {
        if (mHeadView!=null){
            if (position==getItemCount()-1){
                return TYPE_PROGRESS;
            }else if (position==0){
                return TYPE_HEADVIEW;
            }else {
                return TYPE_ITEM;
           }
        }else {
            if (position==getItemCount()-1){
                return TYPE_PROGRESS;
            }else {
                return TYPE_ITEM;
            }
        }
    }


    public abstract void convert(Context mContext, RecyclerView.ViewHolder holder, T t);

    @Override
    public int getItemCount() {
        return mDatas.size()+1;
    }
    public void setLoading(boolean b){
        isLoading=b;
    }

    public    interface OnItemClickListener {
        void onItemClick(View view, int position);
    }

    public    interface onLongItemClickListener {
        void onLongItemClick(View view, int postion);
    }

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

    public void setonLongItemClickListener(onLongItemClickListener listener) {
        this.mLongItemClickListener = listener;
    }
    public void setOnLoadMoreListener(OnLoadMoreListener listener){
        this.mOnLoadMoreListener=listener;
    }

    public interface OnLoadMoreListener{
        void onLoadMore();
    }
    public class ProgressViewHolder extends RecyclerView.ViewHolder{
        public ProgressViewHolder(View itemView) {
            super(itemView);
        }
    }

    public class HeadViewHolder extends RecyclerView.ViewHolder{
        public HeadViewHolder(View itemView) {
            super(itemView);
        }
    }
}

上拉加载和HeadView都是通过ItemViewType实现的，通过不同的position得到不同的ItemViewType，然后在onCreateViewHolder()的时候通过不同的ItemViewType加载不同的布局，创建不同的ViewHolder。

• 使用实例

  1、首先写一个Adapter继承BaseLoadMoreHeaderAdapter，注意要判断holder的类型

    class MyAdapter  extends BaseLoadMoreHeaderAdapter {
        public MyAdapter(Context mContext, RecyclerView recyclerView, List mDatas, int mLayoutId) {
            super(mContext, recyclerView, mDatas, mLayoutId);
        }
  
        @Override
        public void convert(Context mContext, RecyclerView.ViewHolder holder, String s) {
            if (holder instanceof BaseViewHolder){
                ((BaseViewHolder) holder).setText(R.id.tv,s);
            }
        }
    }

  2、在Activity中设置Adapter

        LinearLayoutManager layoutManager=new LinearLayoutManager(this);
        mAdapter=new MyAdapter(this,mRecyclerView,mDatas,R.layout.item);
        mRecyclerView.setLayoutManager(layoutManager);
        View headView= LayoutInflater.from(this).inflate(R.layout.headview,mRecyclerView,false);
        mAdapter.addHeadView(headView);
        mRecyclerView.setAdapter(mAdapter);
  
      mAdapter.setOnLoadMoreListener(new BaseLoadMoreHeaderAdapter.OnLoadMoreListener() {
            @Override
            public void onLoadMore() {
                loadMore();
            }
        });
  
        mAdapter.setOnItemClickListener(new BaseLoadMoreHeaderAdapter.OnItemClickListener() {
            @Override
            public void onItemClick(View view, int position) {
                Toast.makeText(getApplicationContext(),position+"",Toast.LENGTH_SHORT).show();
  
            }
        });

  注意这里，需要先给RecyclerView设置LayoutManager，在加载HeadView（View headView= LayoutInflater.from(this).inflate(R.layout.headview,mRecyclerView,false);）
  否则会报错。

Demo地址

github.com/RaphetS/Rec…