BaseRecyclerViewAdapterHelper源码解读(一) 封装简单的adapter和万能的BaseViewHolder

超、凢脫俗 2022-06-07 10:26 233阅读 0赞

# BaseRecyclerViewAdapterHelper源码解读(一) #

## 1. 封装万能的BaseViewHolder ##

> 这是所有ViewHolder的父类

*  通过SparseArray存储item布局中的控件
 *  通过getView()去获取控件,如果在SparseArray中存在则直接获取,如果不存在则findViewById()然后再插入SparseArray中
 *  设置一些常用操作:设置文本,点击事件,颜色….

SparseArray比HashMap更省内存,在某些条件下性能更好，主要是因为它避免了对key的自动装箱（int转为Integer类型），它内部则是通过两个数组来进行数据存储的，一个存储key，另外一个存储value，为了优化性能，它内部对数据还采取了压缩的方式来表示稀疏数组的数据，从而节约内存空间.

import android.graphics.Bitmap;
    import android.graphics.drawable.Drawable;
    import android.support.annotation.ColorLong;
    import android.support.annotation.DrawableRes;
    import android.support.annotation.FloatRange;
    import android.support.annotation.IdRes;
    import android.support.annotation.NonNull;
    import android.support.annotation.StringRes;
    import android.support.v7.widget.RecyclerView;
    import android.text.SpannableStringBuilder;
    import android.util.SparseArray;
    import android.view.View;
    import android.widget.Checkable;
    import android.widget.ImageView;
    import android.widget.TextView;
    
    /** * author xingyun * create at 2017/9/26 16:54 * description：适用所有RecyclerView的ViewHolder */
    public class BaseViewHolder extends RecyclerView.ViewHolder { 
    
        //子布局中的控件
        private SparseArray<View> mItemViews;
        //子布局
        private View mView;
    
        //初始化ViewHolder
        public BaseViewHolder(View itemView) {
            super(itemView);
            mView = itemView;
            mItemViews = new SparseArray<>();
        }
    
        /** * 获取子控件 * <p> * 子控件的id * * @param viewId 返回子控件 * @return */
        public View getView(@IdRes int viewId) {
            View view = mItemViews.get(viewId);
            if (view == null) {
                view = mView.findViewById(viewId);
                mItemViews.put(viewId, view);
            }
            return view;
        }
    
        /** * 通过strings.xml文件给TextView设置文本 * <p> * 子控件的id * * @param viewId 子控件在strings.xml中的文本 * @param resId 返回子控件 * @return BaseViewHolder */
        public BaseViewHolder setText(@IdRes int viewId, @StringRes int resId) {
            TextView textView = (TextView) getView(viewId);
            textView.setText(resId);
            return this;
        }
    
        /** * 通过String给TextView设置文本 * <p> * 子控件的id * * @param viewId 子控件中的文本 * @param text 返回子控件 * @return BaseViewHolder */
        public BaseViewHolder setText(@IdRes int viewId, String text) {
            TextView textView = (TextView) getView(viewId);
            if (text != null) {
                textView.setText(text);
            } else {
                textView.setText("");
            }
            return this;
        }
    
        /** * 通过SpannableStringBuilder给TextView设置文本 * * @param viewId View的id * @param text 文本 * @return BaseViewHolder */
        public BaseViewHolder setText(@IdRes int viewId, SpannableStringBuilder text) {
            TextView textView = (TextView) getView(viewId);
            if (text != null) {
                textView.setText(text);
            } else {
                textView.setText("");
            }
            return this;
        }
    
        /** * 通过drawable文件夹中的资源设置图片 * * @param viewId view的id * @param resId 文本 * @return BaseViewHolder */
        public BaseViewHolder setImageResource(@IdRes int viewId, @DrawableRes int resId) {
            ImageView imageView = (ImageView) getView(viewId);
            imageView.setImageResource(resId);
            return this;
        }
    
        /** * 通过Bitmap设置图片 * * @param viewId view Id * @param bitmap Bitmap * @return BaseViewHolder */
        public BaseViewHolder setImageBitmap(@IdRes int viewId, @NonNull Bitmap bitmap) {
            ImageView imageView = (ImageView) getView(viewId);
            if (bitmap != null) {
                imageView.setImageBitmap(bitmap);
            }
            return this;
        }
    
        /** * 通过Drawable设置图片 * * @param viewId View的id * @param drawable Drawable * @return BaseViewHolder */
        public BaseViewHolder setImageDrawable(@IdRes int viewId, @NonNull Drawable drawable) {
            ImageView imageView = (ImageView) getView(viewId);
            if (drawable != null) {
                imageView.setImageDrawable(drawable);
            }
            return this;
        }
    
        /** * 通过一串数字设置背景色 * * @param viewId View的id * @param color 颜色值 16进制 * @return BaseViewHolder */
        public BaseViewHolder setBackgroundColor(@IdRes int viewId, @ColorLong int color) {
            View view = getView(viewId);
            view.setBackgroundColor(color);
            return this;
        }
    
        /** * 通过drawable文件夹设置背景图 * * @param viewId View的id * @param backgroundRes Resource * @return BaseViewHolder */
        public BaseViewHolder setBackgroundResource(@IdRes int viewId, @DrawableRes int backgroundRes) {
            View view = getView(viewId);
            view.setBackgroundResource(backgroundRes);
            return this;
        }
    
    
        /** * 通过Drawable设置背景图 * * @param viewId View的id * @param drawable Drawable * @return BaseViewHolder */
        public BaseViewHolder setBackgroundDrawable(@IdRes int viewId, Drawable drawable) {
            View view = getView(viewId);
            if (drawable != null) {
                view.setBackground(drawable);
            }
            return this;
        }
    
        /** * 通过一串数字设置文字颜色 * * @param viewId View的id * @param textColor 颜色值 16进制 * @return BaseViewHolder */
        public BaseViewHolder setTextColor(@IdRes int viewId, @ColorLong int textColor) {
            TextView textView = (TextView) getView(viewId);
            textView.setTextColor(textColor);
            return this;
        }
    
        /** * 通过float设置透明度 * * @param viewId View的id * @param value 透明度 范围:[0.0,1.0] * @return BaseViewHolder */
        public BaseViewHolder setAlpha(@IdRes int viewId, @FloatRange(from = 0.0, to = 1.0) float
                value) {
            getView(viewId).setAlpha(value);
            return this;
        }
    
        /** * 通过boolean类型设置是否显示 * * @param viewId View的id * @param visible 是否可见 true:可见; false:不可见,Gone * @return BaseViewHolder */
        public BaseViewHolder setVisible(@IdRes int viewId, boolean visible) {
            View view = getView(viewId);
            view.setVisibility(visible ? view.VISIBLE : View.GONE);
            return this;
        }
    
        /** * 缓存子控件上界面的数据 * * @param viewId View的id * @param tag 需要缓存的数据 * @return BaseViewHolder */
        public BaseViewHolder setTag(@IdRes int viewId, Object tag) {
            View view = getView(viewId);
            view.setTag(tag);
            return this;
        }
    
        /** * 设置某一位置子控件的数据 * * @param viewId View的id * @param key 数据标识 * @param tag 数据 * @return BaseViewHolder */
        public BaseViewHolder setTag(@IdRes int viewId, int key, Object tag) {
            View view = getView(viewId);
            view.setTag(key, tag);
            return this;
        }
    
        /** * 设置子控件是否选中 * * @param viewId View的id * @param checked true:选中 false:未选中 * @return BaseViewHolder */
        public BaseViewHolder setChecked(@IdRes int viewId, boolean checked) {
            Checkable checkable = (Checkable) getView(viewId);
            checkable.setChecked(checked);
            return this;
        }
    
        /** * 设置子控件的点击事件 * * @param viewId View的id * @param listener OnClickListener监听器 * @return BaseViewHolder */
        public BaseViewHolder setOnClickListener(@IdRes int viewId, @NonNull View.OnClickListener
                listener) {
            View view = getView(viewId);
            if (listener != null) {
                view.setOnClickListener(listener);
            }
            return this;
        }
    
        /** * 设置子控件的触摸事件 * * @param viewId View的id * @param listener OnTouchListener * @return BaseViewHolder */
        public BaseViewHolder setOnTouchListener(@IdRes int viewId, @NonNull View.OnTouchListener
                listener) {
            View view = getView(viewId);
            if (listener != null) {
                view.setOnTouchListener(listener);
            }
            return this;
        }
    
        /** * 设置子控件的长按事件 * * @param viewId View的id * @param listener OnLongClickListener * @return BaseViewHolder */
        public BaseViewHolder setOnLongClickListener(@IdRes int viewId, @NonNull View
                .OnLongClickListener
            listener) {
            View view = getView(viewId);
            if (listener != null) {
                view.setOnLongClickListener(listener);
            }
            return this;
        }
    }

## 2. 封装简单的Adapter ##

*  将重复的方法那些全部抽取到父类(Abstract)免得每次都重复写
 *  父类的泛型是 Bean对象,BaseViewHolder
 *  在onCreateViewHolder()里面写点击事件比较好,因为在onBindViewHolder()里面写的话,每次都要去绑定,会产生多余的消耗.
 *  然后onBindViewHolder()方法是需要每个子类去实现的,我们可以提供一个convert()方法在里面,暴露给外面实现,用于绑定数据.
 *  添加item,移除item->封装
 *  然后封装item点击事件,item长按事件

package com.xfhy.basequickadapter;
    
    import android.content.Context;
    import android.support.annotation.IntRange;
    import android.support.annotation.NonNull;
    import android.support.v7.widget.RecyclerView;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    
    import java.util.List;
    
    /** * author feiyang * create at 2017/10/16 15:45 * description： */
    public abstract class BaseQuickAdapter<T, K extends BaseViewHolder> extends RecyclerView .Adapter<K> { 
    
        private Context mContext;
        /** * 数据集合 */
        private List<T> dataList;
        /** * RecyclerView中普通item的布局id */
        private int layoutResId;
        /** * 子项item点击事件 */
        private OnItemClickListener onItemClickListener;
        /** * 子项item长按事件 */
        private OnItemLongClickListener onItemLongClickListener;
    
        public BaseQuickAdapter(Context context) {
            this.mContext = context;
        }
    
        /** * 此构造方法必须调用 * * @param context Context * @param layoutResId 子项普通item布局 * @param dataList 子项数据集合 */
        public BaseQuickAdapter(Context context, int layoutResId, List<T> dataList) {
            this.mContext = context;
            this.layoutResId = layoutResId;
            this.dataList = dataList;
        }
    
        @Override
        public K onCreateViewHolder(ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(mContext).inflate(layoutResId, parent, false);
            final BaseViewHolder baseViewHolder = new BaseViewHolder(view);
    
            // item点击事件
            if (onItemClickListener != null) {
                view.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        onItemClickListener.onItemClick(v, baseViewHolder.getLayoutPosition());
                    }
                });
            }
    
            // item长按事件
            if (onItemLongClickListener != null) {
                view.setOnLongClickListener(new View.OnLongClickListener() {
                    @Override
                    public boolean onLongClick(View v) {
                        return onItemLongClickListener.onLongClick(v, baseViewHolder
                                .getLayoutPosition());
                    }
                });
            }
            return (K) baseViewHolder;
        }
    
        @Override
        public void onBindViewHolder(K holder, int position) {
            convert(holder, dataList.get(position));
        }
    
        @Override
        public int getItemCount() {
            return dataList == null ? 0 : dataList.size();
        }
    
        /** * 绑定数据 * * @param holder BaseViewHolder * @param item item数据 */
        protected abstract void convert(BaseViewHolder holder, T item);
    
        /** * 设置item点击事件 * * @param onItemClickListener OnItemClickListener */
        public void setOnItemClickListener(@NonNull OnItemClickListener
                                                   onItemClickListener) {
            this.onItemClickListener = onItemClickListener;
        }
    
        /** * 设置item长按事件 * * @param onItemLongClickListener OnItemLongClickListener */
        public void setOnItemLongClickListener(@NonNull OnItemLongClickListener
                                                       onItemLongClickListener) {
            this.onItemLongClickListener = onItemLongClickListener;
        }
    
        /** * item点击监听器 */
        public interface OnItemClickListener { 
            /** * item点击事件回调 * * @param view 触发事件View * @param position 触发事件的view所在RecyclerView中的位置 */
            void onItemClick(View view, int position);
        }
    
        /** * item长按监听器 */
        public interface OnItemLongClickListener { 
            /** * item长按事件回调 * * @param view 触发事件View * @param position 触发事件的view所在RecyclerView中的位置 * @return 是否消费 */
            boolean onLongClick(View view, int position);
        }
    
        /** * 删除item * * @param position 删除item的位置 */
        public void removeItem(@IntRange(from = 0) int position) {
            if (dataList == null) {
                return;
            }
            if (position >= dataList.size()) {
                return;
            }
    
            dataList.remove(position);
            notifyItemRemoved(position);
        }
    
        /** * 新增item * * @param position 新增item位置 * @param item item数据 */
        public void addItem(@IntRange(from = 0) int position, @NonNull T item) {
            if (dataList == null) {
                return;
            }
            if (position > dataList.size()) {
                return;
            }
            dataList.add(position, item);
            notifyItemInserted(position);
        }
    
    }