android - 如何同时运行多个 MaterialContainerTransform 转换？

Question

我正在尝试使用 MaterialContainerTransform 转换同时为两组 View 设置动画。但是，使用下面的代码，只有第一个转换正确运行，而第二个从开始状态跳转到结束状态没有动画。单独测试时，两者都按应有的方式运行。在互联网上搜索了几个小时后，我至今找不到任何解决方案。任何帮助，将不胜感激!

val transform = TransitionSet().apply {
    ordering = TransitionSet.ORDERING_TOGETHER

    addTransition(MaterialContainerTransform().apply {
        startView = startViewA
        endView = endViewA

        addTarget(endViewA)

        pathMotion = MaterialArcMotion()
        scrimColor = Color.TRANSPARENT
    })

    addTransition(MaterialContainerTransform().apply {
        startView = startViewB
        endView = endViewB

        addTarget(endViewB)

        pathMotion = MaterialArcMotion()
        scrimColor = Color.TRANSPARENT
    })
}

TransitionManager.beginDelayedTransition(viewContainer, transform)

startViewA?.visibility = View.GONE
endViewA?.visibility = View.VISIBLE
endViewB?.visibility = View.INVISIBLE
startViewB?.visibility = View.VISIBLE

Answer 1

MaterialContainerTransform 转换在底层使用了可绘制对象在两个状态之间进行动画处理。可绘制对象作为覆盖添加到 android.R.id.content默认情况下( Root View )。
我的猜测是，由于两个可绘制对象都作为叠加层添加到同一 View 中，因此其中一个被完全覆盖。我需要看一下 View 覆盖系统以确保。
但是 MaterialContainerTransform 中有一个方法可以让您设置哪个 View 将使用可绘制对象作为叠加层。

  /**
   * Set the id of the View whose overlay this transition will be added to.
   *
   * <p>This can be used to limit the bounds of the animation (including the background scrim) to
   * the bounds of the provided drawing view, and also have the animation drawn at the relative
   * z-order of the drawing view.
   *
   * <p>By default, the {@code drawingViewId} will be {@code android.R.id.content}. Additionally, if
   * {@code drawingViewId} is the same as the end View's id, {@code MaterialContainerTransform} will
   * add the transition's drawable to the {@code drawingViewId}'s parent instead.
   *
   * <p>If the drawing view cannot be found during the initialization of the {@code
   * MaterialContainerTransform}, then an {@link IllegalArgumentException} will be thrown.
   */
public void setDrawingViewId(@IdRes int drawingViewId) {
this.drawingViewId = drawingViewId;
}

使用此方法为您的一个转换设置不同的“绘图 View ”，我认为这可以解决它。