对Recycler进行动画处理逐一查看项目 [英] Animate RecyclerView items one by one

问题描述

我正在为我的应用程序中的RecyclerView项目设置动画.我尝试在适配器中使用此代码:

I'm trying to animate my RecyclerView items in my app. I tried using this code in my adapter:

    public override void OnBindViewHolder(RecyclerView.ViewHolder holder, int position)
    {
        myHolder = holder as MyView;
        if (position > mCurrentPosition)
        {
            int currentAnim = Android.Resource.Animation.SlideInLeft;
            SetAnimation(holder.ItemView, currentAnim);
            mCurrentPosition = position;
        }

    }

    private void SetAnimation(View view, int currentAnim)
    {

        Animation anim = AnimationUtils.LoadAnimation(mContext, currentAnim);
        anim.SetInterpolator(mContext, Android.Resource.Interpolator.Bounce);
        view.StartAnimation(anim);
    }

但是，因为创建视图时我的所有项目都一起显示，而在用户单击按钮时没有添加，所以所有项目都一起动画.

However, because all of my items appear together when the view is created, and not added when the user clicks a button, for example, all of the items animate together.

我希望这些项目按照它们的位置顺序一个接一个地动画.
这怎么可能?

I want the items to animate one after the other, in the order of their position.
How is this possible to do?

推荐答案

这是怎么回事:

public override void OnBindViewHolder(RecyclerView.ViewHolder holder, int position)
{
    myHolder = holder as MyView;
    if (position > mCurrentPosition)
    {
        Handler h = new Handler();
        int currentAnim = Android.Resource.Animation.SlideInLeft;
        Action myAction = () => 
        {
            SetAnimation(holder.ItemView, currentAnim);
        };

        h.PostDelayed(myAction, 1000);


        mCurrentPosition = position;
    }

}

更新:如果要对所有项目进行动画处理，则应将逻辑代码放在适配器之外.
例如，在活动中，为RecyleView设置适配器后

Update: if you want to animate all items in order, you should put logic code out side an adapter.
For example, in activity, after set adapter for RecyleView

   List<YourObject> data; // your data list for RecycleView

   // CALL this code after set adapter for RecycleView
   Handler h = new Handler();
   int currentAnim = Android.Resource.Animation.SlideInLeft;
   Action myAction = () => 
   {     
      // assume you use LinearLayoutManager  for RecyecleView
        View itemView = linearLayoutManager.findViewByPosition(0);
        StartAnimation(itemView, 0);
   };

   h.PostDelayed(myAction, 1000);


   private void StartAnimation(View view, int position)
    {

        Animation anim = AnimationUtils.LoadAnimation(mContext, currentAnim);
        anim.SetInterpolator(mContext, Android.Resource.Interpolator.Bounce);
        view.StartAnimation(anim);
        anim.AnimationEnd += (sender, e) =>
        {
            // animate next item

            ++position;
            if (position < data.size()) // data is your array list
            {

                // assume you use LinearLayoutManager  for RecyecleView
                View itemView = linearLayoutManager.findViewByPosition(position);
                if (itemView != null)
                {
                    StartAnimation(itemView, position);
                }
            }
        }
    }

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