动态修改RecyclerView中的列数以及图像的大小

Question

我已经能够使用GridLayout动态地更改RecyclerView中的列数2-1，但另外我需要更改高度，以便当它是1列时，图像大小大于2列行中的图像大小。

我已经看到，通过StaggedGridLayoutManager，我可以调整大小，但我不知道如何做到这两个。

val gridLayoutManager=gridLayoutManager（requireContext（），2）

    binding.recycler.layoutManager=gridLayoutManager

    gridLayoutManager.spanSizeLookup=object:GridLayoutManager.SpanSizeLookup(){
        override fun getSpanSize(position: Int): Int {
            return if((position+1)%3==0){
                2

            }else{
                1

            }
        }


 Glide.with(binding.root)
        .asBitmap()
        .load(bindObject.image)
        .apply(RequestOptions().centerCrop())
        .apply(

            RequestOptions()
                .override(160, 160))

        .into(binding.image!!)
}

类HomeAdapter（私有val项：可变列表，val视图模型：HomeViewModel）：GlobalAdapter（项）{override fun onCreateViewHolder（父级：ViewGroup，viewType:Int）：GlobalViewHolder{val inflater=LayoutFlater.from（父级.上下文）

    return HomeViewHolder(DataBindingUtil.inflate(inflater, R.layout.item_news2, parent, false),
        viewModel)
}

override fun onBindViewHolder(holder: GlobalViewHolder<News>, position: Int) {
    holder.bind(items[position])
}

fun addItems(items: List<News>?) {
    if (items != null) {
        this.items.addAll(items)
        notifyDataSetChanged()
    }
}

}

Answer 1

您可以定义多个视图类型

<?xml version="1.0" encoding="utf-8"?>
<ImageView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/imageViewSmall"
    android:layout_width="match_parent"
    android:layout_height="100dp" <!-- Smaller size -->
    />

item_large

<?xml version="1.0" encoding="utf-8"?>
<ImageView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/imageViewLarge"
    android:layout_width="match_parent"
    android:layout_height="250dp" <!-- Bigger size -->
    />

然后，您可以使用getItemViewType方法来定义应根据您的条件显示的视图类型（（位置1）%3==0）：

private const val ITEM_VIEW_TYPE_SMALL = 0
private const val ITEM_VIEW_TYPE_LARGE = 1

class HomeAdapter(
    private val items: MutableList, 
    val viewModel: HomeViewModel
): RecyclerView.Adapter<RecyclerView.ViewHolder>() { 

    override fun getItemViewType(position: Int): Int = if ((position+1) % 3 == 0) {
        // 2 column item, return the small image
        ITEM_VIEW_TYPE_SMALL
    } else {
        // 1 column item, return the large image
        ITEM_VIEW_TYPE_LARGE
    }
    
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder { 
        val inflater = LayoutInflater.from(parent.context)
        if (viewType == ITEM_VIEW_TYPE_SMALL) return SmallViewHolder(ItemSmallBinding.inflate(inflater, parent, false))
        return LargeViewHolder(ItemLargeBinding.inflate(inflater, parent, false))
    }

    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
        holder.bind(...) // Pass the image url here
    }

    fun addItems(items: List<News>?) {
        if (items != null) {
            this.items.addAll(items)
            notifyDataSetChanged()
        }
    }

    // Small image view holder
    class SmallViewHolder(private val binding: ItemSmallBinding) : RecyclerView.ViewHolder(binding.root) {
        fun bind(image: String) {
            // Set the image in imageViewSmall
        }
    }

    // Large image view holder
    class LargeViewHolder(private val binding: ItemLargeBinding) : RecyclerView.ViewHolder(binding.root) {
        fun bind(image: String) {
            // Set the image in imageViewLarge
        }
    }
}