Question

我已使用RecyclerViewAdapter

实施了以下LinearLayoutManager

class WaterSummaryListAdapter(private var dataList: List<WaterSummaryListItem>): RecyclerView.Adapter<RecyclerView.ViewHolder>() {

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
        val v = LayoutInflater.from(parent.context)
                .inflate(R.layout.list_row_water_summary,
                        parent,
                        false)
        return ItemViewHolder(v)
    }

    override fun getItemCount(): Int = dataList.size

    override fun onBindViewHolder(holder: RecyclerView.ViewHolder?, position: Int) {
        val dataItem = dataList[position]

        if (holder is ItemViewHolder){
            holder.update(dataItem)
        }
    }

    inner class ItemViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {

        private var date = itemView.itemDateSummaryList
        private var value = itemView.waterValue

        fun update(item: WaterSummaryListItem){
            this.date.text = item.date
            this.value.text = item.volume.toString()
        }

    }

    fun changeValueOf(itemNo: Int, value: Float){
        dataList[itemNo].volume = value
        notifyDataSetChanged()
    }
}

但是在滚动方面，它不能平滑滚动。它突然停了下来。我甚至试过.setHasFixedSize(true)，但即使这样也行不通。

recyclerView = view.summaryListRecyclerView
val manager = LinearLayoutManager(context)
adapter = WaterSummaryListAdapter(mSummaryListItems)
recyclerView.layoutManager = manager
recyclerView.adapter = adapter
recyclerView.setHasFixedSize(true)

以上是我如何将适配器实现到回收站视图。

Answer 1

您需要按以下方式设置布局

recyclerView.layoutManager = LinearLayoutManager(activity, LinearLayout.VERTICAL, false)
recyclerView.adapter = MyAdapter(yourList)

Answer 2

在holder.update(dataItem)方法正文

中写入轻量代码

Answer 3

删除onBindViewHolder中的if条件并直接调用update方法

if（holder是ItemViewHolder）{}

holder.update(dataItem)

Answer 4

您可以使用SpeedyLinearLayoutManager

SpeedyLinearLayoutManager linearLayoutManager = new SpeedyLinearLayoutManager(this);
        linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        Adapter myAdapter = new Adapter(myContext);
        myRecyclerView.setLayoutManager(linearLayoutManager);
        myRecyclerView.setAdapter(myAdapter);



public class SpeedyLinearLayoutManager extends LinearLayoutManager {

        private static final float MILLISECONDS_PER_INCH = 6f; //default is 25f 
        // set the speed here 

        public SpeedyLinearLayoutManager(Context context) {
            super(context);
        }

        public SpeedyLinearLayoutManager(Context context, int orientation, boolean reverseLayout) {
            super(context, orientation, reverseLayout);
        }

        public SpeedyLinearLayoutManager(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
            super(context, attrs, defStyleAttr, defStyleRes);
        }

        @Override
        public boolean canScrollVertically() {
            //Similarly you can customize "canScrollHorizontally()" for managing horizontal scroll
            return CommonUtils.IsContactActivityScrollEnabled && super.canScrollVertically();
        }

        @Override
        public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state, int position) {

            final LinearSmoothScroller linearSmoothScroller = new LinearSmoothScroller(recyclerView.getContext()) {

                @Override
                public PointF computeScrollVectorForPosition(int targetPosition) {
                    return SpeedyLinearLayoutManager.this.computeScrollVectorForPosition(targetPosition);
                }

                @Override
                protected float calculateSpeedPerPixel(DisplayMetrics displayMetrics) {
                    return MILLISECONDS_PER_INCH / displayMetrics.densityDpi;
                }
            };

            linearSmoothScroller.setTargetPosition(position);
            startSmoothScroll(linearSmoothScroller);
        }
    }

Answer 5

首先，您需要更改第一行，

class WaterSummaryListAdapter(private var dataList: List<WaterSummaryListItem>): RecyclerView.Adapter<RecyclerView.ViewHolder>()

与

class WaterSummaryListAdapter(private var dataList: List<WaterSummaryListItem>): RecyclerView.Adapter< WaterSummaryListAdapter.ItemViewHolder>()

更新：删除了不必要的建议，感谢@Viktor Yakunin

Recycler View无法顺利滚动

5 个答案: