Android ViewPager2 全屏图像错误

Question

我正在尝试在 android 中制作全屏图像查看器片段。我正在使用 ViewPager2。当片段开始时，第一个图像出现在顶部。当我向右滑动并返回到第一张图片时，图片居中。为什么第一时间就拔得头筹？

FullScreenImageFragment.kt

class FullScreenImageFragment : Fragment() {
   private var images = arrayListOf<String>()
   private lateinit var binding: FragmentFullScreenBinding
   private lateinit var fullScreenImageSliderAdapter: FullScreenImageSliderAdapter

   override fun onCreateView(
       inflater: LayoutInflater,
       container: ViewGroup?,
       savedInstanceState: Bundle?,
   ): View? {
       binding = FragmentFullScreenBinding.inflate(inflater)
       if (arguments?.getStringArrayList(Constant.IMAGES) != null)
           images = arguments?.getStringArrayList(Constant.IMAGES) as ArrayList<String>

       return binding.root
   }

   override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
       fullScreenImageSliderAdapter = FullScreenImageSliderAdapter()
       binding.fullScreenViewPager.adapter = fullScreenImageSliderAdapter

       TabLayoutMediator(
           binding.intoTabLayout,
           binding.fullScreenViewPager
       )
       { _, _ -> }.attach()

       fullScreenImageSliderAdapter.setList(images)
   }
}

FullScreenImageSliderAdapter.kt

class FullScreenImageSliderAdapter :
    RecyclerView.Adapter<FullScreenImageSliderAdapter.ModelViewHolder>() {
    private lateinit var itemBinding: ImageSliderItemBinding
    private var images = arrayListOf<String>()

    class ModelViewHolder(private val itemBinding: ImageSliderItemBinding) :
        RecyclerView.ViewHolder(itemBinding.root) {
        fun bindItems(s: String) {
            Picasso.get().load(s).into(itemBinding.imageView)
        }
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ModelViewHolder {
        val inflater = LayoutInflater.from(parent.context)
        itemBinding = ImageSliderItemBinding.inflate(inflater, parent, false)
        itemBinding.imageView.scaleType = ImageView.ScaleType.CENTER
        return ModelViewHolder(itemBinding)
    }

    override fun getItemCount(): Int {
        return images.size
    }

    override fun onBindViewHolder(holder: ModelViewHolder, position: Int) {
        holder.bindItems(images[position])
    }

    fun setList(newImages: ArrayList<String>) {
        images.clear()
        images.addAll(newImages)
        notifyDataSetChanged()
    }
}

ImageItem.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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="@drawable/image_slider_item_background">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scaleType="centerCrop"
        android:src="@drawable/placeholder"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>

FragmentFullScreen.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="@color/black">

    <androidx.viewpager2.widget.ViewPager2
        android:id="@+id/fullScreenViewPager"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <com.google.android.material.tabs.TabLayout
        android:id="@+id/into_tab_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        android:background="@android:color/transparent"
        app:tabBackground="@drawable/tab_pager_selector"
        app:tabGravity="center"
        app:tabIndicatorHeight="0dp" />
</FrameLayout>

Answer 1

你能在 xml 文件中试试这个吗：

android:scaleType="center"