animateLayoutChanges does not work well with nested layout?

Question

I have a nested layout like the following:

 <LinearLayout>     <!----Parent layout--->
    <LinearLayout>    <!-----child 1--->
       ...
    </LinearLayout>   <!----child 1 ended--->
    <LinearLayout>    <!-----child 2--->
       ...
    </LinearLayout>   <!----child 2 ended--->
 </LinearLayout>    <!----Parent endded--->

The problem I am having now is that since all my data items are within child 1 or child 2 Linearlayout, if I add or delete a item the child linearlayout will animated with the effect of animateLayoutChanges but the parent layout will not do any animation. (I have android:animateLayoutChanges set to true for all linear layouts). Especially when I delete an item within child 1 the animation effect becomes weird (basically child 2 will jump up while child 1 is still doing its animation).

Does anybody have any idea how to solve this?

Thanks

UPDATE

Shortly after I posted this question, I found this on android developer's site in the LayoutTransition API.

Using LayoutTransition at multiple levels of a nested view hierarchy may not work due to the interrelationship of the various levels of layout.

So does anyone have any work around suggestions for this issue?

Answer 1

The animateLayoutChanges property makes use of LayoutTransitions, which animate both the layout's children and, from Android 4.0 onward, ancestors in the layout hierarchy all the way to the top of the tree. In Honeycomb, only the layout's children will be animated. See this Android Developers Blog post for details.

Unfortunately, it seems that there's currently no simple way to have the siblings of a layout react to its LayoutTransitions. You could try using a TransitionListener to get notified when the layout's bounds are being changed, and move the sibling views accordingly using Animators. See Chet Haase's second answer in this Google+ post.

EDIT - Turns out there is a way. In Android 4.1+ (API level 16+) you can use a layout transition type CHANGING, which is disabled by default. To enable it in code:

ViewGroup layout = (ViewGroup) findViewById(R.id.yourLayout);
LayoutTransition layoutTransition = layout.getLayoutTransition();
layoutTransition.enableTransitionType(LayoutTransition.CHANGING);

So, in your example, to have child 2 layout animated, you'd need to enable the CHANGING layout transformation for it. The transformation would then be applied when there is a change in the bounds of its parent.

See this DevBytes video for more details.

Answer 2

Ok, after digesting the first answer, I make it simple here, for those who don't get proper animation result when using android:animateLayoutChanges="true" in NESTED layout:

1. Make sure you add android:animateLayoutChanges="true" to the will-be-resized ViewGroup (LinearLayout/RelativeLayout/FrameLayout/CoordinatorLayout).

2. Use setVisibility() to control the visibility of your target View.

3. Listen carefully from here, add android:animateLayoutChanges="true" to the outer ViewGroup of your will-be-resized ViewGroup, this outer ViewGroup must be the one who wraps all the position-changing View affected by the animation.

4. Add following code in your Activity before the setVisibility(), here the rootLinearLayout is the outer ViewGroup I mentioned above:

    LayoutTransition layoutTransition = rootLinearLayout.getLayoutTransition();
    layoutTransition.enableTransitionType(LayoutTransition.CHANGING);
   

---

Before:

After:

---

Reminder: If you miss the 3rd step, you will get null pointer exception.

Good luck!

Answer 3

As a Kotlin Extension

fun ViewGroup.forceLayoutChanges() {
    layoutTransition.enableTransitionType(LayoutTransition.CHANGING)
}

Usage

someContainer.forceLayoutChanges()

---

Notes:

In my experience, this happens when the container is a deep nested layout. For some reason android:animateLayoutChanges="true" just doesn't work, but using this function will force it to work.