Kotlin/RecyclerView：scrollToPositionWithOffset 未显示
[英]Kotlin/RecyclerView: scrollToPositionWithOffset Not Showing Up
问题描述
I wish to understand why I can't seem to use the scrollToPositionWithOffset method on a LinearLayoutManager?
我想了解为什么我似乎无法在 LinearLayoutManager 上使用 scrollToPositionWithOffset 方法？ Please see the image for what I mean :请看图片了解我的意思：
The first line in the image (with scrollToPosition<\/code> ) is scrolling the RecyclerView to make the position (in this case 50) visible<\/strong> - this often means that the selected position shows up at the bottom of the visible RecyclerView (where position 50 first becomes visible after 'scrolling').图像中的第一行（带有scrollToPosition<\/code> ）正在滚动 RecyclerView 以使位置（在本例中为 50）可见<\/strong>- 这通常意味着所选位置显示在可见 RecyclerView 的底部（其中位置 50 首先变为可见之后'滚动'）。 Whereas I want to always show it at the top.而我想始终将其显示在顶部。 From my research, a some-what solution seems to be to use this scrollToPositionWithOffset<\/code> method ( Scroll RecyclerView to show selected item on top<\/a> )根据我的研究，某种解决方案似乎是使用此scrollToPositionWithOffset<\/code>方法（ 滚动 RecyclerView 以在顶部显示所选项目<\/a>）
"3 个解决方案
解决方案1
6 已采纳 2018-09-25 18:28:35
您需要投射从RecyclerView.getLayoutManager()返回的LayoutManager 。
(recyclerview.layoutManager as LinearLayoutManager).scrollToPositionWithOffset
解决方案2
1 2020-12-01 11:58:33
Here is how:方法如下：
recyclerView.apply {
(layoutManager as LinearLayoutManager).scrollToPositionWithOffset(itemPosition, offsetValue)
}
Note that offsetValue could be X if your list/recycleView has horizontal orientation or Y if your list/recycleView has vertical orientation.请注意，如果您的 list/recycleView 具有水平方向，则offsetValue可能是X，如果您的 list/recycleView 具有垂直方向，则offsetValue可能是Y。
解决方案3
0 2022-01-26 15:54:45
To provide a little more context to the other answers, scrollToPositionWithOffset()<\/code> is not a method of LayoutManager (the base class), but one of LinearLayoutManager (and its subclasses).为了为其他答案提供更多上下文， scrollToPositionWithOffset()<\/code>不是 LayoutManager （基类）的方法，而是 LinearLayoutManager （及其子类）之一。 My assumption is that the reasoning here was that such a method is not necessarily applicable (or could be ambiguous) for other LayoutManagers.我的假设是这里的推理是这样的方法不一定适用于其他 LayoutManagers（或可能是模棱两可的）。 Suppose we have a more "exotic" layout manager which does not organize items as a simple list, but rather in a circular shape.假设我们有一个更“异国情调”的布局管理器，它不会将项目组织为简单的列表，而是以圆形的形式。 What should the offset do in such a case?在这种情况下，偏移量应该怎么做？ Does it represent an extra amount radians\/degrees to add to the scroll?它是否代表要添加到滚动条上的额外弧度\/度数？ Or rather something else?或者更确切地说是别的什么？
In the case of a LinearLayoutManager (and any derived classes), however, it is fairly clear what the offset should do.然而，对于 LinearLayoutManager（和任何派生类），偏移量应该做什么是相当清楚的。 Please correct me if I'm wrong, but I think that's why only LinearLayoutManagers have access to the method, hence requiring a cast of the RecyclerView's LayoutManager.如果我错了，请纠正我，但我认为这就是为什么只有 LinearLayoutManagers 可以访问该方法，因此需要 RecyclerView 的 LayoutManager 的强制转换。
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