编辑:

根据ItemAnimator文档:

该类定义当对适配器进行更改时在项上发生的动画。

因此，除非您将项目逐个添加到RecyclerView并在每次迭代时刷新视图，否则我不认为ItemAnimator是您需要的解决方案。

下面是如何在RecyclerView项出现时使用CustomAdapter进行动画化:

public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.ViewHolder>
{
    private Context context;

    // The items to display in your RecyclerView
    private ArrayList<String> items;
    // Allows to remember the last item shown on screen
    private int lastPosition = -1;

    public static class ViewHolder extends RecyclerView.ViewHolder
    {
        TextView text;
        // You need to retrieve the container (ie the root ViewGroup from your custom_item_layout)
        // It's the view that will be animated
        FrameLayout container;

        public ViewHolder(View itemView)
        {
            super(itemView);
            container = (FrameLayout) itemView.findViewById(R.id.item_layout_container);
            text = (TextView) itemView.findViewById(R.id.item_layout_text);
        }
    }

    public CustomAdapter(ArrayList<String> items, Context context)
    {
        this.items = items;
        this.context = context;
    }

    @Override
    public CustomAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
    {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.custom_item_layout, parent, false);
        return new ViewHolder(v);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position)
    {
        holder.text.setText(items.get(position));

        // Here you apply the animation when the view is bound
        setAnimation(holder.itemView, position);
    }

    /**
     * Here is the key method to apply the animation
     */
    private void setAnimation(View viewToAnimate, int position)
    {
        // If the bound view wasn't previously displayed on screen, it's animated
        if (position > lastPosition)
        {
            Animation animation = AnimationUtils.loadAnimation(context, android.R.anim.slide_in_left);
            viewToAnimate.startAnimation(animation);
            lastPosition = position;
        }
    }
}

你的custom_item_layout看起来像这样:

<FrameLayout
    android:id="@+id/item_layout_container"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:id="@+id/item_layout_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceListItemSmall"
        android:gravity="center_vertical"
        android:minHeight="?android:attr/listPreferredItemHeightSmall"/>

</FrameLayout>

有关CustomAdapters和RecyclerView的更多信息，请参阅官方文档中的培训。

快速滚动的问题

使用这种方法可能会导致快速滚动的问题。视图可以在动画发生时被重用。为了避免这种情况，建议在分离动画时清除动画。

    @Override
    public void onViewDetachedFromWindow(final RecyclerView.ViewHolder holder)
    {
        ((CustomViewHolder)holder).clearAnimation();
    }

CustomViewHolder:

    public void clearAnimation()
    {
        mRootLayout.clearAnimation();
    }

旧答案:

看看加布里埃尔·马里奥蒂的记录，我很确定你会找到你想要的。他为RecyclerView提供了简单的itemanimator，如SlideInItemAnimator或SlideScaleItemAnimator。

我认为，最好这样使用它:(在RecyclerView适配器重写一个方法)

override fun onViewAttachedToWindow(holder: ViewHolder) {
    super.onViewAttachedToWindow(holder)

    setBindAnimation(holder)
}

如果你想在RV中添加每个动画。

当Recyclerview项目第一次出现时，我动画淡出如下所示的代码。也许这对某人有用。

private final static int FADE_DURATION = 1000; //FADE_DURATION in milliseconds

@Override
public void onBindViewHolder(ViewHolder holder, int position) {

    holder.getTextView().setText("some text");

    // Set the view to fade in
    setFadeAnimation(holder.itemView);            
}

private void setFadeAnimation(View view) {
    AlphaAnimation anim = new AlphaAnimation(0.0f, 1.0f);
    anim.setDuration(FADE_DURATION);
    view.startAnimation(anim);
}

你也可以用下面的setScaleAnimation()替换setFadeAnimation()，通过从一个点缩放项目来动画它们的外观:

private void setScaleAnimation(View view) {
    ScaleAnimation anim = new ScaleAnimation(0.0f, 1.0f, 0.0f, 1.0f, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
    anim.setDuration(FADE_DURATION);
    view.startAnimation(anim);
}

上面的代码有一些缺陷，当你滚动RecyclerView项总是褪色或缩放。如果你愿意，你可以添加代码，只允许动画在包含RecyclerView的片段或活动第一次创建时发生(例如，在创建时获得系统时间，只允许动画在第一个FADE_DURATION毫秒)。

在您的recyclerview适配器中创建此方法

private void setZoomInAnimation(View view) {
        Animation zoomIn = AnimationUtils.loadAnimation(context, R.anim.zoomin);// animation file 
        view.startAnimation(zoomIn);
    }

最后在onBindViewHolder中添加这行代码

setZoomInAnimation（holder.itemView）;

就像下面那样扩展你的适配器

public class RankingAdapter extends AnimatedRecyclerView<RankingAdapter.ViewHolder> 

并添加super方法到onBindViewHolder

@Override
    public void onBindViewHolder(ViewHolder holder, final int position) {
        super.onBindViewHolder(holder, position);

这是一种自动创建动画适配器的方法比如Basheer AL-MOMANI

import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.Animation;
import android.view.animation.ScaleAnimation;

import java.util.Random;

/**
 * Created by eliaszkubala on 24.02.2017.
 */
public class AnimatedRecyclerView<T extends RecyclerView.ViewHolder> extends RecyclerView.Adapter<T> {


    @Override
    public T onCreateViewHolder(ViewGroup parent, int viewType) {
        return null;
    }

    @Override
    public void onBindViewHolder(T holder, int position) {
        setAnimation(holder.itemView, position);
    }

    @Override
    public int getItemCount() {
        return 0;
    }

    protected int mLastPosition = -1;

    protected void setAnimation(View viewToAnimate, int position) {
        if (position > mLastPosition) {
            ScaleAnimation anim = new ScaleAnimation(0.0f, 1.0f, 0.0f, 1.0f, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
            anim.setDuration(new Random().nextInt(501));//to make duration random number between [0,501)
            viewToAnimate.startAnimation(anim);
            mLastPosition = position;
        }
    }

}

在2019年, 我建议把所有的项目动画放到ItemAnimator中。

让我们从在循环视图中声明动画器开始:

with(view.recycler_view) {
adapter = Adapter()
itemAnimator = CustomAnimator()
}

然后声明自定义动画器，

class CustomAnimator() : DefaultItemAnimator() {

     override fun animateAppearance(
       holder: RecyclerView.ViewHolder,
       preInfo: ItemHolderInfo?,
       postInfo: ItemHolderInfo): Boolean{} // declare  what happens when a item appears on the recycler view

     override fun animatePersistence(
       holder: RecyclerView.ViewHolder,
       preInfo: ItemHolderInfo,
       postInfo: ItemHolderInfo): Boolean {} // declare animation for items that persist in a recycler view even when the items change

}

与上面的类似，还有一个用于消失的animatedisappear，用于添加的animateAdd，用于更改的animateChange和移动的animateMove。

重要的一点是在它们内部调用正确的动画调度器。