可折叠设备的桌面模式

dependencies {
    ...
    // 成文时使用如下的版本号，Exoplayer 最新版本号详见 https://github.com/google/ExoPlayer/releases
    implementation 'com.google.android.exoplayer:exoplayer-core:2.14.1'
    implementation 'com.google.android.exoplayer:exoplayer-ui:2.14.1'

    implementation 'androidx.constraintlayout:constraintlayout:2.1.0-rc01'
    implementation 'androidx.window:window:1.0.0-beta01'

    ...
}

<androidx.constraintlayout.motion.widget.MotionLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/root"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/black"
    app:layoutDescription="@xml/activity_main_scene"
    tools:context=".MainActivity">

    <com.google.android.exoplayer2.ui.PlayerView
        android:id="@+id/player_view"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintBottom_toTopOf="@+id/fold"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:use_controller="false" />

    <androidx.constraintlayout.widget.ReactiveGuide
        android:id="@+id/fold"
        app:reactiveGuide_valueId="@id/fold"
        app:reactiveGuide_animateChange="true"
        app:reactiveGuide_applyToAllConstraintSets="true"
        android:orientation="horizontal"
        app:layout_constraintGuide_end="0dp"
        android:layout_height="wrap_content"
        android:layout_width="wrap_content" />

    <com.google.android.exoplayer2.ui.PlayerControlView
        android:id="@+id/control_view"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:background="@color/black"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/fold" />

</androidx.constraintlayout.motion.widget.MotionLayout>

override fun onStart() {
        super.onStart()
        initializePlayer()
        layoutUpdatesJob = uiScope.launch {
            WindowInfoRepository.windowLayoutInfo
                .collect { newLayoutInfo ->
                    onLayoutInfoChanged(newLayoutInfo)
                }
        }
    }

    override fun onStop() {
        super.onStop()
        layoutUpdatesJob?.cancel()
        releasePlayer()
    }

private fun onLayoutInfoChanged(newLayoutInfo: WindowLayoutInfo) {
        if (newLayoutInfo.displayFeatures.isEmpty()) {
            // 如果当前屏幕没有显示特征可用，我们可能正位于副屏观看、
            // 不可折叠屏幕或是位于可折叠的主屏但处于分屏模式。
            centerPlayer()
        } else {
            newLayoutInfo.displayFeatures.filterIsInstance(FoldingFeature::class.java)
                .firstOrNull { feature -> isInTabletopMode(feature) }
                ?.let { foldingFeature ->
                    val fold = foldPosition(binding.root, foldingFeature)
                    foldPlayer(fold)
                } ?: run {
                centerPlayer()
            }
        }
    }

private fun centerPlayer() {
        ConstraintLayout.getSharedValues().fireNewValue(R.id.fold, 0)
        binding.playerView.useController = true // 使用内嵌画面的控件
    }

    private fun foldPlayer(fold: Int) {
        ConstraintLayout.getSharedValues().fireNewValue(R.id.fold, fold)
        binding.playerView.useController = false // 使用位于屏幕底部一侧的控件
    }

    /**
     * 返回折叠处相对于布局的位置 
     */
    fun foldPosition(view: View, foldingFeature: FoldingFeature): Int {
        val splitRect = getFeatureBoundsInWindow(foldingFeature, view)
        splitRect?.let {
            return view.height.minus(splitRect.top)
        }

        return 0
    }

    /**
     * 获取 displayFeature 变换到视图坐标系的边界和它当前在窗口中的位置。
     * 这里的计算中默认会包含内边距。
     */
    private fun getFeatureBoundsInWindow(
        displayFeature: DisplayFeature,
        view: View,
        includePadding: Boolean = true
    ): Rect? {
        // 视图在窗口中的位置要与显示特征在同一坐标空间中。
        val viewLocationInWindow = IntArray(2)
        view.getLocationInWindow(viewLocationInWindow)

        // 将窗口中的 displayFeature 边界矩形与视图的边界矩形相交以裁剪边界。
        val viewRect = Rect(
            viewLocationInWindow[0], viewLocationInWindow[1],
            viewLocationInWindow[0] + view.width, viewLocationInWindow[1] + view.height
        )

        // 如果需要的话，包含内边距
        if (includePadding) {
            viewRect.left += view.paddingLeft
            viewRect.top += view.paddingTop
            viewRect.right -= view.paddingRight
            viewRect.bottom -= view.paddingBottom
        }

        val featureRectInView = Rect(displayFeature.bounds)
        val intersects = featureRectInView.intersect(viewRect)

        // 检查 displayFeature 与目标视图是否完全重叠
        if ((featureRectInView.width() == 0 && featureRectInView.height() == 0) ||
            !intersects
        ) {
            return null
        }

        // 将显示特征坐标偏移至视图坐标空间起始点
        featureRectInView.offset(-viewLocationInWindow[0], -viewLocationInWindow[1])

        return featureRectInView
 }