Android - NestedScrollView内的RecyclerView上的性能问题

Question

我有一个NestedScrollView在RecyclerView和一个RelativeLayout位于内..

基本上就是这样

<NestedScrollView>

<RelativeLayout> //To contain the stuffs inside

    <RelativeLayout /> // Contains a `TextView` and a `ProgressBar`

    <RecyclerView /> // The most important thing.. Maybe

</RelativeLayout>

</NestedScrollView>

我正在使用一个CustomLinearLayoutManager并且recyclerView.setNestedScrollingEnabled(false);为了滚动两个RelativeLayout和RecyclerView一起,否则,只有RecyclerView会滚动,RelativeLayout它将保持在它的顶部.

每当RecyclerView加载新数据时,它会冻结3-5秒,这对用户体验非常不利..这就是CustomLayoutManager我正在使用的..

public class CustomLayoutManager extends LinearLayoutManager {

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

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

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

    private int[] mMeasuredDimension = new int[2];

    /**
     * Disable predictive animations. There is a bug in RecyclerView which causes views that
     * are being reloaded to pull invalid ViewHolders from the internal recycler stack if the
     * adapter size has decreased since the ViewHolder was recycled.
     */
    @Override
    public boolean supportsPredictiveItemAnimations() {
        return false;
    }

    @Override
    public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state,
                          int widthSpec, int heightSpec) {
        final int widthMode = View.MeasureSpec.getMode(widthSpec);
        final int heightMode = View.MeasureSpec.getMode(heightSpec);
        final int widthSize = View.MeasureSpec.getSize(widthSpec);
        final int heightSize = View.MeasureSpec.getSize(heightSpec);
        int width = 0;
        int height = 0;
        for (int i = 0; i < getItemCount(); i++) {
            if (getOrientation() == HORIZONTAL) {
                measureScrapChild(recycler, i,
                        View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                        heightSpec,
                        mMeasuredDimension);

                width = width + mMeasuredDimension[0];
                if (i == 0) {
                    height = mMeasuredDimension[1];
                }
            } else {
                measureScrapChild(recycler, i,
                        widthSpec,
                        View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                        mMeasuredDimension);
                height = height + mMeasuredDimension[1];
                if (i == 0) {
                    width = mMeasuredDimension[0];
                }
            }
        }
        switch (widthMode) {
            case View.MeasureSpec.EXACTLY:
                width = widthSize;
            case View.MeasureSpec.AT_MOST:
            case View.MeasureSpec.UNSPECIFIED:
        }

        switch (heightMode) {
            case View.MeasureSpec.EXACTLY:
                height = heightSize;
            case View.MeasureSpec.AT_MOST:
            case View.MeasureSpec.UNSPECIFIED:
        }

        setMeasuredDimension(width, height);
    }

    private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec,
                                   int heightSpec, int[] measuredDimension) {
        View view = recycler.getViewForPosition(position);
        recycler.bindViewToPosition(view, position);
        if (view != null) {
            RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
            int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec,
                    getPaddingLeft() + getPaddingRight(), p.width);
            int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
                    getPaddingTop() + getPaddingBottom(), p.height);
            view.measure(childWidthSpec, childHeightSpec);
            measuredDimension[0] = view.getMeasuredWidth() + p.leftMargin + p.rightMargin;
            measuredDimension[1] = view.getMeasuredHeight() + p.bottomMargin + p.topMargin;
            recycler.recycleView(view);
        }
    }
}

我实际上只复制了CustomLayoutManager另一个SO答案,它可能是也可能不是问题..