How to implement ItemAnimator of RecyclerView to d

问题:

In my project I need disable the "change" animation of RecyclerView while notifyItemChanged.

I investigated in the source of RecyclerView and had overridden android.support.v7.widget.DefaultItemAnimator as below:

private static  class ItemAnimator extends DefaultItemAnimator
{
    @Override
    public boolean animateChange(RecyclerView.ViewHolder oldHolder, RecyclerView.ViewHolder newHolder, int fromX, int fromY, int toX, int toY) {
        if(oldHolder != null)
        {
            oldHolder.itemView.setVisibility(View.INVISIBLE);
            dispatchChangeFinished(oldHolder, true);
        }

        if(newHolder != null)
        {
            dispatchChangeFinished(newHolder, false);
        }

        return false;
    }
}

But I am not sure if I match the spec of the Google document: RecyclerView.ItemAnimator.animateChange

According to my understanding source code, if I do not override the method properly, the oldHolder will not be recycled.

Please help me figure out how to override animateChange in a correct way.

回答1:

I have found the correct solution to just remove the animateChange.

It's very simple. Google has implemented the functionality.

((SimpleItemAnimator) RecyclerView.getItemAnimator()).setSupportsChangeAnimations(false);

Documentation: setSupportsChangeAnimations

回答2:

I had the same problem. When calling notifyItemChanged there was a red overlay flashing. After experimenting around with your code I finally removed the default Animator by simply calling

recyclerView.setItemAnimator(null);

on the RecyclerView.

回答3:

@Kenny answer didn't work anymore because google remove method setSupportsChangeAnimations() (but why?) in support library 23.1.0.

In some case setChangeDuration(0) can work as workaround.

@edit I suggest use something like that:

  RecyclerView.ItemAnimator animator = recyclerView.getItemAnimator();
        if (animator instanceof SimpleItemAnimator) {
            ((SimpleItemAnimator) animator).setSupportsChangeAnimations(false);
        }

回答4:

If found a solution, for everyone who wants to keep all the animations given by the DefaultItemAnimator, but getting rid of the "blink" animation that occurs every time the view is updated.

First, get the source code of DefaultItemAnimator. Create a class with the same name in your project.

Second, set the ItemAnimator to a new instance of your modified DefaultItemAnimator, like so:

recyclerView.setItemAnimator(new MyItemAnimator());

Then, go in the new classes source code and locate the method

animateChangeImpl(final ChangeInfo changeInfo) { ... }

Now, we simply have to locate the method calls changing alpha values. Find the following two lines and remove the .alpha(0) and .alpha(1)

oldViewAnim.alpha(0).setListener(new VpaListenerAdapter() { ... }
newViewAnimation.translationX(0).translationY(0).setDuration(getChangeDuration()).alpha(1).setListener(new VpaListenerAdapter() { ... }

like so

oldViewAnim.setListener(new VpaListenerAdapter() { ... }
newViewAnimation.translationX(0).translationY(0).setDuration(getChangeDuration()).setListener(new VpaListenerAdapter() { ... }

回答5:

Just if someone stumbles like me:
Somehow setSupportsChangeAnimations(false) didn't work for me, but recyclerView.getItemAnimator().setChangeDuration(0) has just removed the animation nicely.

回答6:

The easiest solution is to extend DefaultItemAnimator and set setSupportsChangeAnimations to false right in the constructor:

public class DefaultItemAnimatorNoChange extends DefaultItemAnimator {
    public DefaultItemAnimatorNoChange() {
        setSupportsChangeAnimations(false);
    }
}

回答7:

I've created an Extention Class, to disable animation

import androidx.recyclerview.widget.RecyclerView
import androidx.recyclerview.widget.SimpleItemAnimator

fun RecyclerView.disableAnimation() {
    this.getItemAnimator()?.let {
        if (it is SimpleItemAnimator) it.supportsChangeAnimations = false
    }
}

You can call it like this:

recyclerView.disableAnimation()

回答8:

Nothing of the above solutions worked for me. What worked was using the TransitionManager and setting the scene transition to null

TransitionManager.go(new Scene(recyclerView), null);

To re-enable the default animation you can create a new AutoTransition and set it to the same method above:

AutoTransition autoTransition = new AutoTransition();
TransitionManager.go(new Scene(recyclerView), autoTransition);