封装 RecyclerAdapter

Posted 2022-12-02 AAA啊哈

背景

超多的地方用到了 RecyclerView，要是每次都 new 一个 RecyclerAdapter, 就显得很麻烦。
so, 封装 Adapter ，让每次使用的时候，只要完成相关布局即可。

BaseBean

所有 Bean 文件都要继承 BaseBean，viewType 的意义是该 bean 文件所对应的布局，通过设置 viewType 来加载不同的布局。

public class BaseBean implements Serializable 

    private int viewType = Flag.DefaultData.none;

    public int getViewType() 
        return viewType;
    

    public void setViewType(int viewType) 
        this.viewType = viewType;
    

BaseViewHolder

公共的ViewHolder，基本不用再变化的文件。
ViewSugar 专门进行数据处理，糖衣炮弹，每次只要包装他就可以了。

public class BaseViewHolder extends RecyclerView.ViewHolder 

    private View itemView;
    protected Context context;

    public BaseViewHolder(Context context, View itemView) 
        super(itemView);
        ButterKnife.bind(this, itemView);
        this.itemView = itemView;
        this.context = context;
    
    public View getItemView() 
        return itemView;
    

    public static BaseViewHolder createViewHolder(Context context, View itemView) 
        return new BaseViewHolder(context, itemView);
    

    public static BaseViewHolder createViewHolder(Context context,
                                                  ViewGroup parent, int layoutId) 
        View itemView = LayoutInflater.from(context).inflate(layoutId, parent,
                false);
        return new BaseViewHolder(context, itemView);
    

    public void setTag(ViewSugar viewItem) 
        // 设置 tag 文件，不能直接设置 tag，需要设置相应的 key，才不会造成冲突
        itemView.setTag(R.integer.sugar, viewItem);

    

    public ViewSugar getTag() 
        Object tag = itemView.getTag(R.integer.sugar);
        if (tag != null
                && tag instanceof ViewSugar) 
            return (ViewSugar) tag;
        
        return null;
    

不同布局，都要创建一个实现类来继承 ViewSugar 。
getLayoutId() 方法，用于返回该布局的 layoutId，bind（）方法用来处理数据。

public abstract class ViewSugar 
    protected Context context;
    protected ViewGroup parent;
    protected BaseViewHolder baseViewHolder;
    protected View rootView;

    public ViewSugar(Context context, ViewGroup parent) 
        this.context = context;
        this.parent = parent;
        baseViewHolder = createViewHolder(getLayoutId());
        rootView = baseViewHolder.getItemView();
        ButterKnife.bind(this, rootView);
    

    public abstract @LayoutRes int getLayoutId();


    public abstract <T extends BaseBean> void bind(T obj);

    private BaseViewHolder createViewHolder(int layoutId) 
        return BaseViewHolder.createViewHolder(context, parent, layoutId);
    

    public BaseViewHolder getViewHolder() 
        baseViewHolder.setTag(this);
        return baseViewHolder;
    

ViewHolderFactory

这个类根据不同的 itemType 来获取不同的 ViewSugar 相对应的 ViewHolder, 用在 Adapter 的 onCreateViewHolder 方法中。

public class ViewHolderFactory 

    public static BaseViewHolder getViewHolder(Context context, ViewGroup parent, int type) 
        ViewSugar viewSugar = null;
        switch (type) 
            case 101:
                // 在这里获取 ViewSugar 的实现类
                break;
        
        if (viewSugar != null) 
            return viewSugar.getViewHolder();
        
        return null;
    

BaseRecyclerAdapter

首先需要创建一个点击监听接口：

public interface OnItemClickListener 
    void onItemClicked(int position, Object obj);

    boolean onItemLongClicked(int position, Object obj);

public class BaseRecyclerAdapter<T extends BaseBean> extends RecyclerView.Adapter<BaseViewHolder> 

    protected Context context;

    protected List<T> dataList = new ArrayList<>();
    private OnItemClickListener onItemClickListener;

    public BaseRecyclerAdapter(Context context) 
        this.context = context;
    

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

    public void init(@NonNull List<T> data) 
        this.dataList.clear();
        this.dataList.addAll(data);
    

    public void clear() 
        this.dataList.clear();
    

    public void addAll(@NonNull List<T> data) 
        this.dataList.addAll(data);
    

    public void add(@NonNull T data) 
        this.dataList.add(data);
    

    public void remove(int i) 
        this.dataList.remove(i);
    

    public void remove(@NonNull T t) 
        if (this.dataList.contains(t)) 
            dataList.remove(t);
        
    

    public boolean contains(@NonNull T data) 
        if (dataList.isEmpty()) 
            return false;
         else if (dataList.contains(data)) 
            return true;
        
        return false;
    

    public List<T> getData() 
        return dataList;
    

    public T getItem(int index) 
        if (!dataList.isEmpty() && index >= 0 && index < dataList.size()) 
            return dataList.get(index);
         else 
            return null;
        
    

    public void replaceItemByPos(int pos, T item) 
        if (pos < 0 || pos >= dataList.size() || item == null) 
            return;
        
        dataList.remove(pos);
        dataList.add(pos, item);
    

    public void replaceItemList(int start, List<T> list) 
        if (start >= dataList.size() || list == null || list.isEmpty()) 
            return;
        
        for (int i = start; i < start + list.size(); i++) 

            if (start < dataList.size()) 
                dataList.remove(start);
             else 
                break;
            
        

        if (start >= dataList.size()) 
            dataList.addAll(list);
         else 
            dataList.addAll(start, list);
        
    

    @Override
    public int getItemViewType(int position) 
        return dataList.get(position).getViewType();
    


    @Override
    public BaseViewHolder onCreateViewHolder(ViewGroup parent, int viewType) 
        return ViewHolderFactory.getViewHolder(context, parent, viewType);
    

    @Override
    public void onBindViewHolder(final BaseViewHolder holder, int position) 
        if (holder.getTag() != null) 
            ViewSugar viewSugar = holder.getTag();
            viewSugar.bind(dataList.get(position));
            View itemView = holder.getItemView();
            itemView.setOnClickListener(new View.OnClickListener() 
                @Override
                public void onClick(View v) 
                    if (onItemClickListener != null) 
                        onItemClickListener.onItemClicked(
                                holder.getAdapterPosition()
                                , dataList.get(holder.getAdapterPosition()));
                    
                
            );
            itemView.setOnLongClickListener(new View.OnLongClickListener() 
                @Override
                public boolean onLongClick(View v) 
                    return onItemClickListener != null
                            && onItemClickListener.onItemLongClicked(holder.getAdapterPosition()
                            , dataList.get(holder.getAdapterPosition()));
                
            );
        
    

    @Override
    public int getItemCount() 
        return dataList.size();
    

举个例子

创建一个 ViewSugar 实现类：

public class ViewHolderWhat extends ViewSugar 

    @BindView(R.id.view_item_user_name_tv)
    TextView mUserNameTv;

    public static ViewSugar getInstance(Context context, ViewGroup parent) 
        return new ViewHolderWhat (context, parent);
    


    private ViewHolderWhat (Context context, ViewGroup parent) 
        super(context, parent);
    

    @Override
    public int getLayoutId() 
        return R.layout.view_item_post_comment;
    

    @Override
    public <T extends BaseBean> void bind(final T obj) 
        if (obj != null && obj instanceof WhatBean )
            WhatBean bean = (WhatBean ) obj;
            mUserNameTv.setText(bean.getUserName());
        
    

在 ViewHolderFactory 中添加进去：

public class ViewHolderFactory 

    public static BaseViewHolder getViewHolder(Context context, ViewGroup parent, int type) 
        ViewSugar viewSugar = null;
        switch (type) 
            case 101:
                // 在这里获取 ViewSugar 的实现类
                 viewSugar = ViewHolderWhat.getInstance(context, parent);
                break;
        
        if (viewSugar != null) 
            return viewSugar.getViewHolder();
        
        return null;
    

重写 bean 文件的 getViewType() 方法，或者在获取到bean 对象的时候 setViewType()。

public class WhatBean extends BaseBean 
    @Override
    public int getViewType() 
        return 101;
    

使用 BaseRecyclerAdapter 加载 这个 WhatBean 即可展示对应的布局。

建议 ViewType 的值声明到一个单独的文件，以方便管理。