10-Adapter的封装以及使用

一、Adapter的封装

由于我们的RecycleView在项目中很常用，因此有必要对Adapter进行封装。

封装的原则是：

BaseAdapter的代码如下：

import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import java.util.ArrayList;
import java.util.List;

/**
 * Adapter的简单封装
 */
public abstract class BaseAdapter<T, H extends BaseViewHolder> extends RecyclerView.Adapter<BaseViewHolder> {

    protected static final String TAG = BaseAdapter.class.getSimpleName();

    protected final Context context;

    protected final int layoutResId;

    protected List<T> datas;

    private OnItemClickListener mOnItemClickListener = null;


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

    public BaseAdapter(Context context, int layoutResId) {
        this(context, layoutResId, null);
    }


    public BaseAdapter(Context context, int layoutResId, List<T> datas) {
        this.datas = datas == null ? new ArrayList<T>() : datas;
        this.context = context;
        this.layoutResId = layoutResId;
    }

    @Override
    public BaseViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
        View view = LayoutInflater.from(viewGroup.getContext()).inflate(layoutResId, viewGroup, false);
        BaseViewHolder vh = new BaseViewHolder(view, mOnItemClickListener);
        return vh;
    }

    @Override
    public void onBindViewHolder(BaseViewHolder holder, int position) {
        T item = getItem(position);
        convert((H) holder, item);
    }

    @Override
    public int getItemCount() {
        if (datas == null || datas.size() <= 0)
            return 0;

        return datas.size();
    }

    public T getItem(int position) {
        if (position >= datas.size()) return null;
        return datas.get(position);
    }

    /**
     * 清空数据
     */
    public void clearData() {
        int size = datas.size();
        datas.clear();
        notifyItemRangeRemoved(0, size);
    }

    /**
     * 下拉刷新，清除原有数据，添加新数据
     *
     * @param newData
     */
    public void refreshData(List<T> newData) {
        datas.clear();
        datas.addAll(newData);
        notifyItemRangeChanged(0, datas.size());
    }

    /**
     * 在原来数据的末尾追加新数据
     *
     * @param moreData
     */
    public void loadMoreData(List<T> moreData) {
        int lastPosition = datas.size();
        datas.addAll(lastPosition, moreData);
        notifyItemRangeInserted(lastPosition, moreData.size());
    }

    /**
     * Implement this method and use the helper to adapt the view to the given item.
     *
     * @param viewHoder A fully initialized helper.
     * @param item      The item that needs to be displayed.
     */
    protected abstract void convert(H viewHoder, T item);


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

    }
}

BaseViewHolder的代码如下：

import android.support.v7.widget.RecyclerView;
import android.util.SparseArray;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

/**
 * 封装的ViewHolder
 */
public class BaseViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

    //使用数组把条目中的View保存起来
    private SparseArray<View> views;

    private BaseAdapter.OnItemClickListener mOnItemClickListener;

    public BaseViewHolder(View itemView, BaseAdapter.OnItemClickListener onItemClickListener) {
        super(itemView);
        itemView.setOnClickListener(this);

        this.mOnItemClickListener = onItemClickListener;
        this.views = new SparseArray<View>();
    }

    public TextView getTextView(int viewId) {
        return retrieveView(viewId);
    }

    public Button getButton(int viewId) {
        return retrieveView(viewId);
    }

    public ImageView getImageView(int viewId) {
        return retrieveView(viewId);
    }

    public View getView(int viewId) {
        return retrieveView(viewId);
    }


    protected <T extends View> T retrieveView(int viewId) {
        View view = views.get(viewId);
        if (view == null) {
            view = itemView.findViewById(viewId);
            views.put(viewId, view);
        }
        return (T) view;
    }

    @Override
    public void onClick(View v) {
        if (mOnItemClickListener != null) {
            mOnItemClickListener.onItemClick(v, getLayoutPosition());
        }
    }
}

为了使用方便，再提供一个SimpleAdapter：

import android.content.Context;

import java.util.List;

/**
 * 一个简易的adapter
 */
public abstract class SimpleAdapter<T> extends BaseAdapter<T, BaseViewHolder> {

    public SimpleAdapter(Context context, int layoutResId) {
        super(context, layoutResId);
    }

    public SimpleAdapter(Context context, int layoutResId, List<T> datas) {
        super(context, layoutResId, datas);
    }
}

二、封装Adapter的基本使用

1、使用

mAdapter = new SimpleAdapter<Page.Ware>(getActivity(), R.layout.item_hot_wares) {
    @Override
    protected void convert(BaseViewHolder holder, final Page.Ware item) {

        SimpleDraweeView s = (SimpleDraweeView) holder.getView(R.id.drawee_view);
        s.setImageURI(Uri.parse(item.getImgUrl()));
        holder.getTextView(R.id.text_title).setText(item.getName());
        holder.getTextView(R.id.text_price).setText(item.getPrice() + "");
        holder.getButton(R.id.btn_add).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(getActivity(), item.getName(), Toast.LENGTH_SHORT).show();
            }
        });
    }
};

2、还可以进行点击监听

mAdapter.setOnItemClickListener(new BaseAdapter.OnItemClickListener() {
    @Override
    public void onItemClick(View view, int position) {
        
    }
});

如果觉得我的文字对你有所帮助的话，欢迎关注我的公众号：

公众号：Android开发进阶

我的群欢迎大家进来探讨各种技术与非技术的话题，有兴趣的朋友们加我私人微信huannan88，我拉你进群交（♂）流（♀）。