Android 2 个 RecyclerView 之间的共享元素转换

Question

我在 2 个活动（MainActivity 和 DetailActivity）中的 2 个 RecyclerView 项之间使用默认共享元素转换。从 MainActivity 到 DetailActivity 的动画工作正常，但如果用户滚动到 DetailActivity 中的新项目，则重新进入动画会将项目移到顶部。我将 Android Developers Blog for my needs. Here's the Github Link 上共享的示例修改为我的代码。我也曾尝试在 DetailActivity 上禁用退出动画，并尝试将退出动画更改为仅淡入淡出，但这几乎就像退出动画根本没有受到尊重。

这是一个视频演示（问题可以在最后几秒看到）：

主要活动：

class MainActivity : AppCompatActivity(), ListImageAdapter.ListImageClickListener {

    private lateinit var imageData: ImageData
    private lateinit var listImageAdapter: ListImageAdapter

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        setupGallery()
        prepareTransitions()
    }

    @SuppressLint("RestrictedApi")
    override fun onListImageClick(position: Int, imageView: ImageView) {
        val intent = Intent(this, DetailActivity::class.java)
        intent.putExtra("IMAGE_DATA", imageData)
        val activityOptions = ActivityOptions.makeSceneTransitionAnimation(this, imageView,
                ViewCompat.getTransitionName(imageView))

        startActivityForResult(intent, 101, activityOptions.toBundle())
    }

    override fun onActivityReenter(resultCode: Int, data: Intent?) {
        data?.let { intent ->
            if (intent.hasExtra("IMAGE_DATA")) {
                imageData = intent.getParcelableExtra("IMAGE_DATA")
                listImageAdapter.images = imageData.images
                val position = imageData.images.indexOfFirst { it.selected }
                itemGallery.scrollToPosition(position)

            }
        }
        super.onActivityReenter(resultCode, data)
    }

    private fun setupGallery() {
        imageData = ImageData(getGalleryItems())
        val snapHelper = PagerSnapHelper()
        snapHelper.attachToRecyclerView(itemGallery)
        listImageAdapter = ListImageAdapter(imageData.images, this)
        itemGallery.adapter = listImageAdapter
        itemGallery.addOnScrollListener(object : RecyclerView.OnScrollListener() {
            override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
                super.onScrollStateChanged(recyclerView, newState)
                if (newState == RecyclerView.SCROLL_STATE_IDLE) {
                    val selectedView = snapHelper.findSnapView(itemGallery.layoutManager)
                    selectedView?.let {
                        val selectedPosition = itemGallery.layoutManager?.getPosition(selectedView)
                        selectedPosition?.let { onMediumGalleryItemHighlighted(selectedPosition) }
                    }

                }
            }
        })

    }

    private fun onMediumGalleryItemHighlighted(position: Int) {
        imageData.images = imageData.images.mapIndexed { index, galleryItem ->
            when {
                index == position -> galleryItem.copy(selected = true)
                galleryItem.selected -> galleryItem.copy(selected = false)
                else -> galleryItem
            }
        }
    }

    private fun prepareTransitions() {

        setExitSharedElementCallback(
                object : SharedElementCallback() {
                    override fun onMapSharedElements(names: List<String>?, sharedElements: MutableMap<String, View>?) {
                        val selectedPosition = imageData.images.indexOfFirst { it.selected }
                        val selectedViewHolder = itemGallery
                                .findViewHolderForAdapterPosition(selectedPosition)
                        if (selectedViewHolder?.itemView == null) {
                            return
                        }
                        sharedElements!![names!![0]] = selectedViewHolder.itemView.findViewById(R.id.listItemImage)
                    }
                })
    }

    private fun getGalleryItems(): List<Image> {
        return listOf(
                Image(R.drawable.cat, true),
                Image(R.drawable.lion, false),
                Image(R.drawable.tortoise, false)
        )
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:animateLayoutChanges="false"
    >

    <View android:id="@+id/otherContent"
        android:layout_width="match_parent"
        android:layout_height="256dp"
        android:background="@android:color/holo_green_light"
        />

    <android.support.v7.widget.RecyclerView
        android:id="@+id/itemGallery"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="horizontal"
        android:layout_below="@+id/otherContent"
        app:layoutManager="android.support.v7.widget.LinearLayoutManager" />


</RelativeLayout>

DetailActivity:

class DetailActivity : AppCompatActivity() {

    private lateinit var detailImageAdapter: DetailImageAdapter
    private lateinit var imageData: ImageData


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_detail)
        imageData = intent.extras.getParcelable("IMAGE_DATA")
        initViews()
        prepareTransitions()
        resetScrolledPosition()
    }

    private fun initViews() {
        val snapHelper = PagerSnapHelper()
        snapHelper.attachToRecyclerView(detailGallery)
        detailImageAdapter = DetailImageAdapter(imageData.images)
        detailGallery.adapter = detailImageAdapter
        detailGallery.addOnScrollListener(object : RecyclerView.OnScrollListener() {
            override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
                super.onScrollStateChanged(recyclerView, newState)
                if (newState == RecyclerView.SCROLL_STATE_IDLE) {
                    val selectedView = snapHelper.findSnapView(detailGallery.layoutManager)
                    selectedView?.let {
                        val selectedPosition = detailGallery.layoutManager?.getPosition(selectedView)
                        selectedPosition?.let { onItemSelected(selectedPosition) }
                    }
                }
            }
        })
    }

    private fun resetScrolledPosition() {
        val position = imageData.images.indexOfFirst { it.selected }
        imageData.images = imageData.images.mapIndexed { index, galleryItem ->
            when {
                index == position -> {
                    galleryItem.copy(selected = true)
                }
                galleryItem.selected -> galleryItem.copy(selected = false)
                else -> galleryItem
            }
        }
        detailImageAdapter.images = imageData.images
        detailGallery.scrollToPosition(position)
        supportStartPostponedEnterTransition()
    }


    private fun onItemSelected(position: Int) {
        imageData.images = imageData.images.mapIndexed { index, galleryItem ->
            when {
                index == position -> galleryItem.copy(selected = true)
                galleryItem.selected -> galleryItem.copy(selected = false)
                else -> galleryItem
            }
        }
    }

    override fun onBackPressed() {
        var resultIntent = Intent()
        resultIntent = resultIntent.putExtra("IMAGE_DATA", imageData)
        setResult(Activity.RESULT_OK, resultIntent)
        super.onBackPressed()

    }

    private fun prepareTransitions() {

        setEnterSharedElementCallback(
                object : SharedElementCallback() {
                    override fun onMapSharedElements(names: List<String>?, sharedElements: MutableMap<String, View>?) {
                        val selectedPosition = imageData.images.indexOfFirst { it.selected }
                        val selectedViewHolder = detailGallery.findViewHolderForAdapterPosition(selectedPosition)
                        if (selectedViewHolder?.itemView == null) {
                            return
                        }
                        sharedElements!![names!![0]] = selectedViewHolder.itemView.findViewById(R.id.detailItemImage)
                    }
                })
    }

}

activity_detail.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/black"
    android:animateLayoutChanges="false"
    >
    <android.support.v7.widget.RecyclerView
        android:id="@+id/detailGallery"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="horizontal"
        app:layoutManager="android.support.v7.widget.LinearLayoutManager" />

</FrameLayout>

Answer 1

请检查 GithubLink

上的共享元素转换代码

SharedElementTransition-master.zip 是从您的源代码中更新的代码，其中 Transition 在两个 RecyclerView 之间工作。

android-gallery-master.zip 是另一个代码，其中 Transition 在 RecyclerView 和 ViewPager 之间工作。

希望对您有用。我会尽快添加解释。

Android 2 个 RecyclerView 之间的共享元素转换

Android shared element transition between 2 RecyclerViews

android

android-animation

android-transitions

shared-element-transition