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