android - Recyclerview 删除之前选中的item的动画

Question

我为 recyclerview 的选定项目设置动画，我希望在选择另一个项目时删除前一个项目的动画

我的代码如下；

主要 Activity 代码；

val premiumRecyclerAdapter: RecyclerView = findViewById(R.id.recyclerPremium)


        premiumRecyclerAdapter.layoutManager =
            object : LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false) {
                override fun canScrollVertically(): Boolean {
                    return false
                }

            }

        premiumRecyclerAdapter.itemAnimator = DefaultItemAnimator()
        premiumRecyclerAdapter.adapter = ProfilePremiumRecyclerAdapter(getPremium(), premiumRecyclerAdapter)
        val snapHelper = LinearSnapHelper()
        snapHelper.attachToRecyclerView(premiumRecyclerAdapter)
        premiumRecyclerAdapter.smoothScrollToPosition(1)
        val layoutManager = premiumRecyclerAdapter.layoutManager
        val snapView = snapHelper.findSnapView(layoutManager)
        val snapOnScrollListener = SnapOnScrollListener(snapHelper, SnapOnScrollListener.Behavior.NOTIFY_ON_SCROLL_STATE_IDLE)
        premiumRecyclerAdapter.addOnScrollListener(snapOnScrollListener)

适配器；

class ProfilePremiumRecyclerAdapter(
                                    val profilePremiumList: MutableList<ProfilePremium>, val premiumRecyclerView: RecyclerView) : RecyclerView.Adapter<ProfilePremiumRecyclerAdapter.ModelViewHolder>() {

    class ModelViewHolder(view: View) : RecyclerView.ViewHolder(view) {
        val title: TextView = view.findViewById(R.id.txt_premium_title)
        val content: TextView = view.findViewById(R.id.txt_premium_content)
        val lottieAnim: LottieAnimationView = view.findViewById(R.id.lottie_profile_normal)
        var relative_root_profile_popup: ConstraintLayout = view.findViewById(R.id.relative_root_profile_popup)
        fun bindItems(item: ProfilePremium) {



        }


    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ModelViewHolder {
        val view = LayoutInflater.from(parent.context).inflate(R.layout.row_profile_normal, parent, false)

        return ModelViewHolder(view)
    }

    override fun getItemCount(): Int {
        return profilePremiumList.size
    }

    override fun onBindViewHolder(holder: ModelViewHolder, position: Int) {
        holder.bindItems(profilePremiumList.get(position))


    }




}

SnapOnScrollListener;

class SnapOnScrollListener(
    private val snapHelper: SnapHelper,
    var behavior: Behavior = Behavior.NOTIFY_ON_SCROLL,
    var onSnapPositionChangeListener: OnSnapPositionChangeListener? = null
) : RecyclerView.OnScrollListener() {
    var position = 1
    enum class Behavior {
        NOTIFY_ON_SCROLL,
        NOTIFY_ON_SCROLL_STATE_IDLE
    }
    private var snapPosition = RecyclerView.NO_POSITION
    override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
        if (behavior == Behavior.NOTIFY_ON_SCROLL) {
            maybeNotifySnapPositionChange(recyclerView)

        }
    }
    override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
        if (behavior == Behavior.NOTIFY_ON_SCROLL_STATE_IDLE
            && newState == RecyclerView.SCROLL_STATE_IDLE) {
            maybeNotifySnapPositionChange(recyclerView)
        }
    }
    private fun maybeNotifySnapPositionChange(recyclerView: RecyclerView) {
        val snapPosition = snapHelper.getSnapPosition(recyclerView)
        val snapPositionChanged = this.snapPosition != snapPosition
        if (snapPositionChanged) {
            onSnapPositionChangeListener?.onSnapPositionChange(snapPosition)
            this.snapPosition = snapPosition
            MyLog.log("recyclerview position: $snapPosition")
            position = snapPosition
            recyclerView.postOnAnimation {
                val itemView       = recyclerView.findViewHolderForLayoutPosition(snapPosition)
                Handler().postDelayed({
                itemView!!.itemView.scaleAnimPremium()
                }, 500)
            }
        }
    }
    fun SnapHelper.getSnapPosition(recyclerView: RecyclerView): Int {
        val layoutManager = recyclerView.layoutManager ?: return RecyclerView.NO_POSITION
        val snapView = findSnapView(layoutManager) ?: return RecyclerView.NO_POSITION

        return layoutManager.getPosition(snapView)
    }
}

OnSnapPositionChangeListener;

interface OnSnapPositionChangeListener {

    fun onSnapPositionChange(position: Int)
}

util/Utils.kt 缩放动画高级函数；

fun View.scaleAnimPremium() {
    animate().scaleX(1.1f).start()
    animate().scaleY(1.1f).start()
}

我正在为第 1 项添加动画。我希望在移动到第 2 项时删除第 1 项。所以想把之前选中的item的动画删掉。我的动画允许项目增长/缩放到所选项目的 1.1f.目前这些代码将我想要的缩放动画应用于所选项目。但是其他项目的动画不会回到原来的状态。

我试过了，但是没用:(;

recyclerView.post {
                val itemView       = recyclerView.findViewHolderForLayoutPosition(snapPosition)
                for (i in 0..3 ) {
                    if (i != snapPosition) {

                        val itemViewOther = recyclerView.findViewHolderForLayoutPosition(i)
                        itemViewOther!!.itemView.scaleAnimPremiumClear()

                    }
                }
                Handler().postDelayed({

                itemView!!.itemView.scaleAnimPremium()
                }, 500)
            }

Answer 1

我是这样解决问题的:我将所有选定的值分配到一个数组中，并从上一个选择到达上一个选择。如下;在 arraylist 中，我缺少 arraylist 2 的长度。任何东西的长度都可以至少为 1，所以我少了 2(如果你不这样做，你应该很好地理解 arraylist 的长度和序列概念)。

val arrayList = ArrayList<Int>()

arrayList.add(snapPosition)
            if (arrayList.size > 1){
                val itemViewOther = recyclerView.findViewHolderForLayoutPosition(arrayList[arrayList.size-2])
                itemViewOther!!.itemView.scaleAnimPremiumClear()
                itemViewOther.itemView.updateLayoutParams<RecyclerView.LayoutParams> {
                    marginStart = 20
                }
            }
                val itemView       = recyclerView.findViewHolderForLayoutPosition(snapPosition)

                Handler().postDelayed({

                itemView!!.itemView.scaleAnimPremium()
                }, 500)