RecycleView nests RecycleView, and the internal RecycleView uses FlexboxLayoutManager(context, FlexDirection.ROW, FlexWrap.WRAP), when the number of items is large, it cannot be displayed completely (for example, only 30 items are displayed for 50 items, and they are not displayed after exceeding one screen) about flexbox-layout HOT 4 OPEN

if (sumCrossSize > needsCalcAmount && reachedToIndex) {
    // Stop the calculation if the sum of cross size calculated reached to the point
    // beyond the needsCalcAmount value to avoid unneeded calculation in a
    // RecyclerView.
    // To be precise, the decoration length may be added to the sumCrossSize,
    // but we omit adding the decoration length because even without the decorator
    // length, it's guaranteed that calculation is done at least beyond the
    // needsCalcAmount
    break;
}

if (sumCrossSize > needsCalcAmount && reachedToIndex) {
    // Stop the calculation if the sum of cross size calculated reached to the point
    // beyond the needsCalcAmount value to avoid unneeded calculation in a
    // RecyclerView.
    // To be precise, the decoration length may be added to the sumCrossSize,
    // but we omit adding the decoration length because even without the decorator
    // length, it's guaranteed that calculation is done at least beyond the
    // needsCalcAmount
    // break;
}