Question

I am setting an animation on my view from following the ApiDemo example (see layout_grid_fade.html):

<?xml version="1.0" encoding="utf-8"?>
<gridLayoutAnimation xmlns:android="http://schemas.android.com/apk/res/android"
        android:rowDelay="50%"
        android:directionPriority="column"
        android:animation="@anim/fade" />

and below is my code

mView.startAnimation(AnimationUtils.loadAnimation(ViewModel.this, R.anim.layout_grid_fade));
mView.setImage(modelImages.get(0).image);

but i get exception dont know why? below is my log trace

FATAL EXCEPTION: main
java.lang.RuntimeException: Unknown animation name: gridLayoutAnimation
    at android.view.animation.AnimationUtils.createAnimationFromXml(AnimationUtils.java:116)
    at android.view.animation.AnimationUtils.createAnimationFromXml(AnimationUtils.java:83)
    at android.view.animation.AnimationUtils.loadAnimation(AnimationUtils.java:64)
    at nick.kimK.ViewModel$1$1.run(ViewModel.java:72)
    at android.os.Handler.handleCallback(Handler.java:587)
    at android.os.Handler.dispatchMessage(Handler.java:92)
    at android.os.Looper.loop(Looper.java:123)
    at android.app.ActivityThread.main(ActivityThread.java:4627)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:521)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:871)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:629)
    at dalvik.system.NativeStart.main(Native Method)

Answer 1

UPD:
Not every xml in res/anim folder declares an animation. Some of them might declare Animators or LayoutAnimationControllers. Those are not Animations, thus they can’t be loaded with the loadAnimation() call.

—

It looks like the gridLayoutAnimation tag describes not a particular basic animation type but rather a GridLayoutAnimationController. So it can be loaded directly with AnimationUtils.loadAnimation() but rather should be set to a ViewGroup (a layout) throuh layoutAnimation property. If you still want to obtain the AnimationController instance in code, use AnimationUtils.loadLayoutAnimation() method:

LayoutAnimationController layoutAnimation = AnimationUtils.loadLayoutAnimation(ViewModel.this, R.anim.layout_grid_fade)

But you hardly can use the layoutAnimation in the way you’re doing in your example.
I found this article quite useful for understanding the layout animations.