android RecycleView Adapter简单封装

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<ParamHolderView> {

    private List<ProductParamEntity> list;
    private LayoutInflater mInflater;
    private Context mContext = null;

    public DetailParamAdapter(Context context) {
        this.mContext = context;
        mInflater = LayoutInflater.from(context);
    }

    public void setList(List<ProductParamEntity> 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<T> 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<T> extends RecyclerView.Adapter<BaseRecycleHolder> implements RecyclerViewHelper<T> {

    protected Context mContext;
    protected List<T> mList;
    protected int[] layoutIds;
    protected LayoutInflater mLInflater;

    private SparseArray<View> mConvertViews = new SparseArray<>();

    public BaseRecycleAdapter(Context context, List<T> 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<T> 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<ProductParamEntity> {

    public ParamRecycleAdapter(Context context, List<ProductParamEntity> 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：打包aar，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<T> extends BaseAdapter {
    public Context mContext = null;
    protected LayoutInflater inflaterFactory = null;
    protected List<T> mList = new ArrayList<T>();

    public BasicAdapter() {
        super();
    }

    public BasicAdapter(Context context) {
        this.mContext = context;
        inflaterFactory = LayoutInflater.from(mContext);
    }

    public BasicAdapter(List<T> list) {
        if (list != null) {
            mList = list;
        }
    }

    public BasicAdapter(Context context, List<T> list) {
        this(context);
        this.mList = list;
    }

    public void setList(List<T> list) {
        if (list != null) {
            mList = list;
            notifyDataSetChanged();
        }
    }

    public boolean addList(List<T> 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<T> 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<T> 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 extends View> V inflate(int resource, ViewGroup root, boolean attachToRoot) {
        if (inflaterFactory == null) {
            inflaterFactory = LayoutInflater.from(mContext);
        }
        return (V) inflaterFactory.inflate(resource, root, attachToRoot);
    }

    public <V extends View> V inflate(int resource, ViewGroup root) {
        return inflate(resource, root, root != null);
    }

    public <V extends View> V inflate(int resource) {
        return inflate(resource, null, false);
    }
}

最后贴上RecycleView.Adapter的封装库地址：点击打开链接