constraintlayout.widget.Group 动画不适用于 TransitionManager

Question

有没有人知道为什么constraintlayout.widget.GroupTransitionManager 的动画可见性不起作用？这个小部件不是为这些东西制作的吗？

如果在将视图与组分离后隐藏或显示项目，它会起作用

        <androidx.constraintlayout.widget.Group
            android:id="@+id/cardHeadersGroup"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:visibility="invisible"
            app:constraint_referenced_ids="cardSystemHeader,cardSimpleHeader,cardCombinedHeader"
            app:layout_constraintBottom_toBottomOf="@+id/cardCombinedHeader"
            app:layout_constraintEnd_toEndOf="@+id/cardSystemHeader"
            app:layout_constraintStart_toStartOf="@+id/cardSimpleHeader"
            app:layout_constraintTop_toTopOf="parent"
            tools:visibility="visible"/>

 val headersGroup = binding.cardHeadersGroup

        val slideIn = Slide()
        slideIn.slideEdge = Gravity.BOTTOM
        slideIn.mode = Slide.MODE_IN
        slideIn.addTarget(headersGroup)

        TransitionManager.beginDelayedTransition(binding.root as ViewGroup, slideIn)

        headersGroup.visibility = VISIBLE

Answer 1

我最近一直在使用TransitionManager并且ConstraintLayout.Group发现它非常有问题。

最终我决定转储整个ConstraintLayout.Group并创建一个代码AnimationGroup（类似于in-xml ConstraintLayout.Group）：

class AnimationGroup(vararg val views: View) {
    var visibility: Int = View.INVISIBLE
        set(value) {
            views.forEach { it.visibility = value }
            field = value
        }
}

和一个扩展函数Transition：

private fun Transition.addTarget(animationGroup: AnimationGroup) {
    animationGroup.views.forEach { viewInGroup -> this.addTarget(viewInGroup) }
}

这样您就可以执行以下操作（几乎完全相同的代码，但更简单的 xml - no ConstraintLayout.Group）：

val headersGroup = AnimationGroup(
    binding.cardSystemHeader, 
    binding.cardSimpleHeader, 
    binding.cardCombinedHeader
)

val slideIn = Slide()
slideIn.slideEdge = Gravity.BOTTOM
slideIn.mode = Slide.MODE_IN
slideIn.addTarget(headersGroup)

TransitionManager.beginDelayedTransition(binding.root as ViewGroup, slideIn)

headersGroup.visibility = VISIBLE