如何查看recyclerview+pagersnaphelper

经过反复试验,我找到了解决办法。幸运的是,事情并没有我想象的那么复杂,尽管没有我希望的那么干净。

所以从recyclerview及其适配器开始,使用水平方向的linearlayoutmanager,添加pagersnaphelper等等……然后为了解决这个问题中的特定问题,我对适配器进行了一些调整:

private var orientation: Int? = null

override fun onAttachedToRecyclerView(recyclerView: RecyclerView) {
    super.onAttachedToRecyclerView(recyclerView)
    orientation = (recyclerView.layoutManager as LinearLayoutManager).orientation
}

override fun onBindViewHolder(holder: ViewHolder, position: Int) {
    // Kludge to adjust margins for horizontal, ViewPager style RecyclerView
    if (orientation != LinearLayout.VERTICAL) {
        holder.itemView.layoutParams = (holder.itemView.layoutParams as RecyclerView.LayoutParams).apply {
            val displayMetrics = DisplayMetrics()
            baseActivity.windowManager.defaultDisplay.getMetrics(displayMetrics)
            // To show the edge of the next/previous card on the screen, we'll adjust the width of our MATCH_PARENT card to make
            // it just slightly smaller than the screen. That way, no matter the size of the screen, the card will fill most of
            // it and show a hint of the next cards.
            val widthSubtraction = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 40f, displayMetrics).toInt()
            width = displayMetrics.widthPixels - widthSubtraction
            // We always want the spot card centered. But the RecyclerView will left-align the first card and right-align the
            // last card, since there's no card peeking on that size. We'll adjust the margins in those two places to pad it out
            // so those cards appear centered.
            // Theoretically we SHOULD be able to just use half of the amount we shrank the card by, but for some reason that's
            // not quite right, so I'm adding a fudge factor developed via trial and error to make it look better.
            val fudgeFactor = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 6f, displayMetrics).toInt()
            val endAdjustment = (widthSubtraction / 2) - fudgeFactor
            marginStart = if (position == 0) endAdjustment else 0
            marginEnd = if (position == (itemCount - 1)) endAdjustment else 0
        }
    }
}

当然,你会想改变的 40f 和 6f 为您的用例设置适当的值。

如果您想知道,我有方向检查,因为在我的情况下,同一个适配器用于两个不同的recyclerview。一个是简单的垂直列表。另一个是水平的,功能类似于viewpager,这大大增加了复杂性。