android RecycleView Adapter简单封装-白红宇

早些时候我们使用系统提供个的BaseAdapter的时候为了满足大家的需要，我们总会对BaseAdapter做一层上层的封装，然后对于实际业务我们只需要关心getView里面的View即可，是代码可读性和可维护性更高，特别是在多View的界面，这个优势就体现出来了，自从Android 5.0后系统提供的，先不说效率如何，这个既然是Google为我们提供的，我们姑且用之，不过说实话，对于它的写法不习惯他的人看着很是麻烦，其实这个类无外乎继承自RecyclerView.Adapter然后提供一个HolderView。

如下：

public class DetailParamAdapter extends RecyclerView.Adapter
    
      {    private List
     
       list;    private LayoutInflater mInflater;    private Context mContext = null;    public DetailParamAdapter(Context context) {        this.mContext = context;        mInflater = LayoutInflater.from(context);    }    public void setList(List
      
        list) {        this.list = list;        notifyDataSetChanged();    }    public OnItemClickListener mOnItemClickListener;    public interface OnItemClickListener {        void onItemClick(View view, int position);    }    public void setOnItemClickListener(OnItemClickListener mOnItemClickLitener) {        this.mOnItemClickListener = mOnItemClickLitener;    }    @Override    public ParamHolderView onCreateViewHolder(ViewGroup parent, int viewType) {        View view = mInflater.inflate(R.layout.item_product_param, parent, false);        ParamHolderView holder = new ParamHolderView(view);        return holder;    }    @Override    public void onBindViewHolder(final ParamHolderView holder, final int position) {        ProductParamEntity bean = list.get(position);        if (bean != null) {            holder.itemTitle.setText(bean.title);            holder.itemContent.setText(bean.content);        }    }    @Override    public int getItemCount() {        return list.size();    }}class ParamHolderView extends RecyclerView.ViewHolder {    @BindView(R.id.item_title)    TextView itemTitle;    @BindView(R.id.item_content)    TextView itemContent;    public ParamHolderView(View itemView) {        super(itemView);        ButterKnife.bind(this, itemView);        itemView.setTag(this);    }}

不过我们可不可以对上面的写法来一个精简呢？

其实分析下，adapter对我们有用的就两个方法，一个是获取adapter的View，然后是绑定数据OnBindData，至于数据的来源，我们可以借鉴RecyclerView.Adapter做一个泛型。

有了上面的思路，首先我们要获取adapter的View，然后将它赋给onCreateViewHolder返回的view对象。所以我们的构造可以这么写，

public BaseRecycleAdapter(Context context, List
    
      list, int... layoutIds) {        this.mContext = context;        this.mList = list;        this.layoutIds = layoutIds;        this.mLInflater = LayoutInflater.from(mContext);    }

public BaseRecycleHolder onCreateViewHolder(ViewGroup parent, int viewType) {        if (viewType < 0 || viewType > layoutIds.length) {            throw new ArrayIndexOutOfBoundsException("layoutIndex");        }        if (layoutIds.length == 0) {            throw new IllegalArgumentException("not layoutId");        }        int layoutId = layoutIds[viewType];        View view = mConvertViews.get(layoutId);        if (view == null) {            view = mLInflater.inflate(layoutId, parent, false);        }        BaseRecycleHolder viewHolder = (BaseRecycleHolder) view.getTag();        if (viewHolder == null || viewHolder.getLayoutId() != layoutId) {            viewHolder = new BaseRecycleHolder(mContext, layoutId, view);            return viewHolder;        }        return viewHolder;    }

然后我们需要绑定界面了，由于各个页面的对于的元素不一样，所以这个方法我们需要根据实际情况去动态绑定数据，所以我们需要写一个抽象方法去让用户实现，这个抽象方法主要包含ViewHolder界面，位置，还有Item的元素（其实这个大可以不要）

protected abstract void onBindData(BaseRecycleHolder viewHolder, int position, T item);

@Override    public void onBindViewHolder(BaseRecycleHolder holder, int position) {        final T item = mList.get(position);        onBindData(holder, position, item);    }

当然我们这个Adapter基础的类可能还需要一些常用入add，clear，del等操作方法。其完整的代码如下：

public abstract class BaseRecycleAdapter
    
      extends RecyclerView.Adapter
     
       implements RecyclerViewHelper
      
        {    protected Context mContext;    protected List
       
         mList;    protected int[] layoutIds;    protected LayoutInflater mLInflater;    private SparseArray
        
          mConvertViews = new SparseArray<>();    public BaseRecycleAdapter(Context context, List
         
           list, int... layoutIds) { this.mContext = context; this.mList = list; this.layoutIds = layoutIds; this.mLInflater = LayoutInflater.from(mContext); } @Override public BaseRecycleHolder onCreateViewHolder(ViewGroup parent, int viewType) { if (viewType < 0 || viewType > layoutIds.length) { throw new ArrayIndexOutOfBoundsException("layoutIndex"); } if (layoutIds.length == 0) { throw new IllegalArgumentException("not layoutId"); } int layoutId = layoutIds[viewType]; View view = mConvertViews.get(layoutId); if (view == null) { view = mLInflater.inflate(layoutId, parent, false); } BaseRecycleHolder viewHolder = (BaseRecycleHolder) view.getTag(); if (viewHolder == null || viewHolder.getLayoutId() != layoutId) { viewHolder = new BaseRecycleHolder(mContext, layoutId, view); return viewHolder; } return viewHolder; } @Override public void onBindViewHolder(BaseRecycleHolder holder, int position) { final T item = mList.get(position); onBindData(holder, position, item); } @Override public int getItemCount() { return mList == null ? 0 : mList.size(); } @Override public int getItemViewType(int position) { return getLayoutIndex(position, mList.get(position)); } /** * 指定item布局样式在layoutIds的索引。默认为第一个 */ public int getLayoutIndex(int position, T item) { return 0; } protected abstract void onBindData(BaseRecycleHolder viewHolder, int position, T item); @Override public boolean addAll(List
          
            list) { boolean result = mList.addAll(list); notifyDataSetChanged(); return result; } @Override public boolean addAll(int position, List list) { boolean result = mList.addAll(position, list); notifyDataSetChanged(); return result; } @Override public void add(T data) { mList.add(data); notifyDataSetChanged(); } @Override public void add(int position, T data) { mList.add(position, data); notifyDataSetChanged(); } @Override public void clear() { mList.clear(); notifyDataSetChanged(); } @Override public boolean contains(T data) { return mList.contains(data); } @Override public T getData(int index) { return mList.get(index); } @Override public void modify(T oldData, T newData) { modify(mList.indexOf(oldData), newData); } @Override public void modify(int index, T newData) { mList.set(index, newData); notifyDataSetChanged(); } @Override public boolean remove(T data) { boolean result = mList.remove(data); notifyDataSetChanged(); return result; } @Override public void remove(int index) { mList.remove(index); notifyDataSetChanged(); }}

当然这里还有好多的辅助类，这里就不在详解解释了，那最好我们怎么用呢？很简单，来一个之前的例子：

public class ParamRecycleAdapter extends BaseRecycleAdapter
    
      {    public ParamRecycleAdapter(Context context, List
     
       list) {        super(context, list, R.layout.item_product_param);    }    @Override    protected void onBindData(BaseRecycleHolder viewHolder, int position, ProductParamEntity item) {        viewHolder.setText(R.id.item_title, item.title)                .setText(R.id.item_content, item.content);    }}

我们只要注意上面标颜色的部分即可。我已经将这个封装为一个库文件，如果有需要的可以自己打包aar或者jar，相关资料请参照：，代码已经上传（文章最后）。

对于之前的Baseadapter这里也贴给大家：

public abstract class BasicAdapter
    
      extends BaseAdapter {    public Context mContext = null;    protected LayoutInflater inflaterFactory = null;    protected List
     
       mList = new ArrayList
      
       ();    public BasicAdapter() {        super();    }    public BasicAdapter(Context context) {        this.mContext = context;        inflaterFactory = LayoutInflater.from(mContext);    }    public BasicAdapter(List
       
         list) {        if (list != null) {            mList = list;        }    }    public BasicAdapter(Context context, List
        
          list) {        this(context);        this.mList = list;    }    public void setList(List
         
           list) { if (list != null) { mList = list; notifyDataSetChanged(); } } public boolean addList(List
          
            list) { if (list != null && list.size() > 0) { mList.addAll(list); notifyDataSetChanged(); return true; } return false; } public boolean add(T t) { if (t != null) { mList.add(t); notifyDataSetChanged(); return true; } return false; } public boolean add(int position, T t) { if (t != null && getCount() >= position) { mList.add(position, t); notifyDataSetChanged(); return true; } return false; } public void remove(T t) { if (mList.remove(t)) { notifyDataSetChanged(); } } public void remove(List
           
             list) { if (mList.remove(list)) { notifyDataSetChanged(); } } public void remove(int index) { if (index >= 0 && index < mList.size()) { mList.remove(index); notifyDataSetChanged(); } } public void clear() { if (mList != null) { mList.clear(); notifyDataSetChanged(); } } public List
            
              getList() { return mList; } @Override public int getCount() { if (mList != null && mList.size() > 0) { return mList.size(); } else return 0; } @Override public T getItem(int position) { if (mList!=null){ return mList.get(position); }else return null; } public T getLastItem() { if (mList.size() > 0) { return mList.get(mList.size() - 1); } return null; } @Override public long getItemId(int position) { return position; } public 
             
               V inflate(int resource, ViewGroup root, boolean attachToRoot) { if (inflaterFactory == null) { inflaterFactory = LayoutInflater.from(mContext); } return (V) inflaterFactory.inflate(resource, root, attachToRoot); } public 
              
                V inflate(int resource, ViewGroup root) { return inflate(resource, root, root != null); } public 
               
                 V inflate(int resource) { return inflate(resource, null, false); }}

最后贴上RecycleView.Adapter的封装库地址：