FragmentTransaction setCustomAnimations

_Android_MaterialTransitionTips.md

See: https://workday.github.io/ui/2017/09/05/androidinbox-material-transitions-for-recyclerview

ExplodeFadeOut.kt

class ExplodeFadeOut : Explode() {
    init {
        propagation = null
    }

    override fun onAppear(sceneRoot: ViewGroup?, view: View?, startValues: TransitionValues?,
                          endValues: TransitionValues?): Animator {
        val explodeAnimator = super.onAppear(sceneRoot, view, startValues, endValues)
        val fadeInAnimator = ObjectAnimator.ofFloat(view, View.ALPHA, 0f, 1f)

        return animatorSet(explodeAnimator, fadeInAnimator)
    }

    override fun onDisappear(sceneRoot: ViewGroup?, view: View?, startValues: TransitionValues?,
                             endValues: TransitionValues?): Animator {
        val explodeAnimator = super.onDisappear(sceneRoot, view, startValues, endValues)
        val fadeOutAnimator = ObjectAnimator.ofFloat(view, View.ALPHA, 1f, 0f)

        return animatorSet(explodeAnimator, fadeOutAnimator)
    }

    private fun animatorSet(explodeAnimator: Animator, fadeAnimator: Animator): AnimatorSet {
        val animatorSet = AnimatorSet()
        animatorSet.play(explodeAnimator).with(fadeAnimator)
        return animatorSet
    }
}

ItemFragment.kt

class ItemFragment : Fragment() {


    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        val view = inflater.inflate(R.layout.fragment_item_list, container, false)

        // Set the adapter
        if (view is RecyclerView) {
            with(view) {
                layoutManager = LinearLayoutManager(context)
                adapter = MyItemRecyclerViewAdapter(DummyContent.ITEMS) { v, item ->
                    with(this@ItemFragment) {
                        exitTransition = getListFragmentExitTransition(v)
                        reenterTransition = getListFragmentExitTransition(v)
                    }

                    val f = DetailFragment.newInstance(item).apply {
                        exitTransition = Fade().setInterpolator(AnticipateInterpolator())
                        enterTransition = Fade().setInterpolator(AnticipateInterpolator())
                        reenterTransition = Fade().setInterpolator(DecelerateInterpolator())
                        returnTransition = Fade().setInterpolator(DecelerateInterpolator())

                    }
                    requireFragmentManager().commit {
                        replace(R.id.fragment_container, f)
                            .addToBackStack(DetailFragment::javaClass.name)
//                            .setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN)
                    }
                }
            }
        }
        return view
    }

    companion object {
        @JvmStatic
        fun newInstance() = ItemFragment()
    }

    private fun getListFragmentExitTransition(itemView: View): Transition {
        val epicCenterRect = Rect()
        //itemView is the full-width inbox item's view
        itemView.getGlobalVisibleRect(epicCenterRect)
        // Set Epic center to a imaginary horizontal full width line under the clicked item, so the explosion happens vertically away from it
        epicCenterRect.top = epicCenterRect.bottom
        val exitTransition = ExplodeFadeOut()
        exitTransition.epicenterCallback = object : Transition.EpicenterCallback() {
            override fun onGetEpicenter(transition: Transition): Rect {
                return epicCenterRect
            }
        }
        return exitTransition
    }
}

MainActivity.kt

fun AppCompatActivity.commit(fragment: Fragment) {
    this.supportFragmentManager.commit {
        setCustomAnimations(R.anim.popup_enter, R.anim.popup_exit)
        replace(R.id.fragment_container, fragment)
    }
}

popup_enter.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
     android:shareInterpolator="false">
    <alpha android:fromAlpha="0.8" android:toAlpha="1.0"
           android:interpolator="@android:anim/decelerate_interpolator"
           android:duration="@android:integer/config_shortAnimTime"
    />
    <scale
            android:pivotX="50%"
            android:pivotY="100%"
            android:fromXScale="0.8" android:fromYScale="0.8"
            android:toXScale="1.0" android:toYScale="1.0"
            android:interpolator="@android:anim/decelerate_interpolator"
            android:duration="@android:integer/config_shortAnimTime"
    />
</set>

popup_exit.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
     android:shareInterpolator="false">
    <alpha android:fromAlpha="1.0" android:toAlpha="0.6"
           android:interpolator="@android:anim/accelerate_interpolator"
           android:duration="@android:integer/config_shortAnimTime"
    />
</set>