recyclerview的adapter封装（kotlin）

首先是重写 ViewHolder，参考了鸿洋大神的博客。

class RViewHolder(private val mContext: Context, val convertView: View) : ViewHolder(convertView) {

    private val mViews: SparseArray<View>

    init {
        mViews = SparseArray()
    }

    /**
     * 通过viewId获取控件
     *
     * @param viewId
     * @return
     */
    fun <T : View> getView(viewId: Int): T {
        var view = mViews[viewId]
        if (view == null) {
            view = convertView.findViewById(viewId)
            mViews.put(viewId, view)
        }
        return view as T
    }

    /****以下为辅助方法 */
    /**
     * 设置TextView的值
     *
     * @param viewId
     * @param text
     * @return
     */
    fun setText(viewId: Int, text: String?): RViewHolder {
        val tv = getView<TextView>(viewId)
        tv.text = text
        return this
    }

    fun setImageResource(viewId: Int, resId: Int): RViewHolder {
        val view = getView<ImageView>(viewId)
        view.setImageResource(resId)
        return this
    }

    fun setImageBitmap(viewId: Int, bitmap: Bitmap?): RViewHolder {
        val view = getView<ImageView>(viewId)
        view.setImageBitmap(bitmap)
        return this
    }

    fun setImageDrawable(viewId: Int, drawable: Drawable?): RViewHolder {
        val view = getView<ImageView>(viewId)
        view.setImageDrawable(drawable)
        return this
    }

    fun setBackgroundColor(viewId: Int, color: Int): RViewHolder {
        val view = getView<View>(viewId)
        view.setBackgroundColor(color)
        return this
    }

    fun setBackgroundRes(viewId: Int, backgroundRes: Int): RViewHolder {
        val view = getView<View>(viewId)
        view.setBackgroundResource(backgroundRes)
        return this
    }

    fun setTextColor(viewId: Int, textColor: Int): RViewHolder {
        val view = getView<TextView>(viewId)
        view.setTextColor(textColor)
        return this
    }

    fun setTextColorRes(viewId: Int, textColorRes: Int): RViewHolder {
        val view = getView<TextView>(viewId)
        view.setTextColor(mContext.resources.getColor(textColorRes))
        return this
    }

    @SuppressLint("NewApi")
    fun setAlpha(viewId: Int, value: Float): RViewHolder {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
            getView<View>(viewId).alpha = value
        } else {
            // Pre-honeycomb hack to set Alpha value
            val alpha = AlphaAnimation(value, value)
            alpha.duration = 0
            alpha.fillAfter = true
            getView<View>(viewId)!!.startAnimation(alpha)
        }
        return this
    }

    fun setVisible(viewId: Int, visible: Boolean): RViewHolder {
        val view = getView<View>(viewId)
        view.visibility = if (visible) View.VISIBLE else View.GONE
        return this
    }

    fun linkify(viewId: Int): RViewHolder {
        val view = getView<TextView>(viewId)
        Linkify.addLinks(view, Linkify.ALL)
        return this
    }

    fun setTypeface(typeface: Typeface?, vararg viewIds: Int): RViewHolder {
        for (viewId in viewIds) {
            val view = getView<TextView>(viewId)
            view.typeface = typeface
            view.paintFlags = view.paintFlags or Paint.SUBPIXEL_TEXT_FLAG
        }
        return this
    }

    fun setProgress(viewId: Int, progress: Int): RViewHolder {
        val view = getView<ProgressBar>(viewId)
        view.progress = progress
        return this
    }

    fun setProgress(viewId: Int, progress: Int, max: Int): RViewHolder {
        val view = getView<ProgressBar>(viewId)
        view.max = max
        view.progress = progress
        return this
    }

    fun setMax(viewId: Int, max: Int): RViewHolder {
        val view = getView<ProgressBar>(viewId)
        view.max = max
        return this
    }

    fun setRating(viewId: Int, rating: Float): RViewHolder {
        val view = getView<RatingBar>(viewId)
        view.rating = rating
        return this
    }

    fun setRating(viewId: Int, rating: Float, max: Int): RViewHolder {
        val view = getView<RatingBar>(viewId)
        view.max = max
        view.rating = rating
        return this
    }

    fun setTag(viewId: Int, tag: Any?): RViewHolder {
        val view = getView<View>(viewId)
        view.tag = tag
        return this
    }

    fun setTag(viewId: Int, key: Int, tag: Any?): RViewHolder {
        val view = getView<View>(viewId)
        view.setTag(key, tag)
        return this
    }

    fun setChecked(viewId: Int, checked: Boolean): RViewHolder {
        val view = getView<View>(viewId) as Checkable
        view.isChecked = checked
        return this
    }

    /**
     * 关于事件的
     */
    fun setOnClickListener(
        viewId: Int,
        listener: View.OnClickListener?
    ): RViewHolder {
        val view = getView<View>(viewId)
        view.setOnClickListener(listener)
        return this
    }

    fun setOnTouchListener(
        viewId: Int,
        listener: OnTouchListener?
    ): RViewHolder {
        val view = getView<View>(viewId)
        view.setOnTouchListener(listener)
        return this
    }

    fun setOnLongClickListener(
        viewId: Int,
        listener: OnLongClickListener?
    ): RViewHolder {
        val view = getView<View>(viewId)
        view.setOnLongClickListener(listener)
        return this
    }

    companion object {
        fun createViewHolder(
            context: Context,
            itemView: View
        ): RViewHolder {
            return RViewHolder(context, itemView)
        }

        @JvmStatic
        fun createViewHolder(
            context: Context,
            parent: ViewGroup, layoutId: Int
        ): RViewHolder {
            val itemView = LayoutInflater.from(context).inflate(
                layoutId, parent,
                false
            )
            return RViewHolder(context, itemView)
        }
    }

}

SparseArray对view进行存储，需要的时候可以直接获取进行操作。

继承 RecyclerView.Adapter<RViewHolder>

open class MultiItemTypeAdapter<T>(protected var mContext: Context, var datas: List<T>) : RecyclerView.Adapter<RViewHolder>() {
    protected var itemViewDelegate: ItemViewDelegate<T>? = null
    protected var mOnItemClickListener: OnItemClickListener? = null

    override fun getItemViewType(position: Int): Int {
        //根据传入adapter来判断是否有数据
        return if (datas.size > 0) NOT_EMPTY_VIEW else EMPTY_VIEW
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RViewHolder {
        val layoutId = itemViewDelegate!!.getItemViewLayoutId(viewType)
        val holder = createViewHolder(mContext, parent, layoutId)
        onViewHolderCreated(holder, holder.convertView, viewType)
        setListener(parent, holder, viewType)
        return holder
    }

    fun onViewHolderCreated(
        holder: RViewHolder?,
        itemView: View?,
        viewType: Int
    ) {
    }

    fun convert(holder: RViewHolder, t: T) {
        itemViewDelegate!!.convert(holder, t, holder.adapterPosition)
    }

    fun convertEmptyView(holder: RViewHolder?) {}
    protected fun isEnabled(viewType: Int): Boolean {
        return viewType != EMPTY_VIEW
    }

    protected fun setListener(
        parent: ViewGroup?,
        viewHolder: RViewHolder,
        viewType: Int
    ) {
        if (!isEnabled(viewType)) return
        viewHolder.convertView.setOnClickListener(object : NoDoubleClickListener() {
            override fun onNoDoubleClick(v: View) {
                val position = viewHolder.adapterPosition
                mOnItemClickListener?.onItemClick(v, viewHolder, position)
            }
        })
        viewHolder.convertView.setOnLongClickListener(OnLongClickListener { v ->

            mOnItemClickListener?.let {
                val position = viewHolder.adapterPosition
                return@OnLongClickListener it.onItemLongClick(v, viewHolder, position)
            }
            false
        })
    }

    override fun onBindViewHolder(holder: RViewHolder, position: Int) {
        if (getItemViewType(position) != EMPTY_VIEW) {
            convert(holder, datas[position])
        } else {
            convertEmptyView(holder)
        }
    }

    override fun getItemCount(): Int {
        return if (isEmptyViewShowed) {
            if (datas.isNotEmpty()) datas.size else 1
        } else {
            if (datas.isNotEmpty()) datas.size else 0
        }
    }

    fun setItemViewDelegate(delegate: ItemViewDelegate<T>?): MultiItemTypeAdapter<*> {
        itemViewDelegate = delegate
        return this
    }

    interface OnItemClickListener {
        fun onItemClick(
            view: View?,
            holder: ViewHolder?,
            position: Int
        )

        fun onItemLongClick(
            view: View?,
            holder: ViewHolder?,
            position: Int
        ): Boolean
    }

    fun setOnItemClickListener(onItemClickListener: OnItemClickListener?) {
        mOnItemClickListener = onItemClickListener
    }

    open val isEmptyViewShowed: Boolean
        get() = true

    companion object {
        const val EMPTY_VIEW = 0
        const val NOT_EMPTY_VIEW = 1
    }

}

RVAdapter类的编写

/**
 *
 * @fuction 通用Recylerview Adapter
 * @date 2019/5/22
 * @author zhouruiyong
 */
abstract class RVAdapter<T>(
    mContext: Context,
    protected var mLayoutId: Int,
    mDatas: List<T>
) : MultiItemTypeAdapter<T>(mContext, mDatas) {

    private var emptyId = R.layout.item_empty_layout

    protected abstract fun convert(holder: RViewHolder, t: T, position: Int)

    protected fun getViewLayoutId(viewType: Int): Int {
        return if (viewType == EMPTY_VIEW) { emptyId } else mLayoutId
    }

    fun setEmptyId(emptyId: Int) {
        this.emptyId = emptyId
    }

    init {
        //getItemViewLayoutId重写，则此处layoutId可直接写0
        setItemViewDelegate(object : ItemViewDelegate<T> {
            override fun getItemViewLayoutId(viewType: Int): Int {
                return getViewLayoutId(viewType)
            }

            override fun isForViewType(item: T, position: Int): Boolean {
                return true
            }

            override fun convert(holder: RViewHolder, t: T, position: Int) {
                if (isForViewType(t, position)) {
                    this@RVAdapter.convert(holder, t, position)
                }
            }
        })
    }
}

interface ItemViewDelegate<T> {
    fun getItemViewLayoutId(viewType: Int): Int
    fun isForViewType(item: T, position: Int): Boolean
    fun convert(holder: RViewHolder, t: T, position: Int)
}

以上就是adapter封装。现在看使用。

val layoutManager = LinearLayoutManager(this); //线性布局
recyclerview.layoutManager = layoutManager
homeAdapter = object: RVAdapter<String>(this@AdapterActivity,R.layout.item_rv_txt, mDatas){
  override fun convert(holder: RViewHolder, t: String, position: Int) {
                holder.setText(R.id.txt,mDatas[position])
            }
       }

recyclerview.adapter = homeAdapter
homeAdapter!!.setOnItemClickListener(object:MultiItemTypeAdapter.OnItemClickListener{
            override fun onItemClick(view: View, holder: RecyclerView.ViewHolder, position: Int) {
                TODO("Not yet implemented")
            }

            override fun onItemLongClick(
                view: View,
                holder: RecyclerView.ViewHolder,
                position: Int
            ): Boolean {
                TODO("Not yet implemented")
            }

        })

注意：可以通过重写isEmptyViewShowed的值，决定数据为空时是否显示空布局的样式。

github地址：https://gitee.com/stonezry/AndroidDemo