Android RecyclerView点击宫格处于选择态外框变方框线，Kotlin

Android RecyclerView点击宫格处于选择态外框变方框线，Kotlin

implementation 'com.github.bumptech.glide:glide:4.16.0'

读出手机上所有图片，过滤gif图。加载图片形成4宫格，当点击小格子时候，小格子处于选择态，图片四周矩形红色框选，若再次点击，取消选择。

import android.content.Context
import android.os.Bundle
import android.provider.MediaStore
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.lifecycleScope
import androidx.recyclerview.widget.GridLayoutManager
import androidx.recyclerview.widget.RecyclerView
import androidx.recyclerview.widget.RecyclerView.ViewHolder
import com.bumptech.glide.Glide
import com.google.android.material.imageview.ShapeableImageView
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch
import kotlinx.coroutines.withContext


class MainActivity : AppCompatActivity() {
    companion object {
        const val IMAGE_SIZE = 300
        const val GRID_SIZE = 4

        const val VIEW_TYPE_NORMAL = 1
        const val VIEW_TYPE_SELECTED = 2
    }

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

        val mRecyclerView = findViewById(R.id.recycler_view)
        val layoutManager = GridLayoutManager(this, GRID_SIZE)
        mRecyclerView?.layoutManager = layoutManager

        val adapter = MyAdapter()
        mRecyclerView?.adapter = adapter

        lifecycleScope.launch(Dispatchers.IO) {
            val items = readAllImage(this@MainActivity)
            withContext(Dispatchers.Main) {
                adapter?.dataChanged(items)
            }
        }
    }

    class MyAdapter : RecyclerView.Adapter() {
        private var items = arrayListOf()
        fun dataChanged(l: ArrayList) {
            items = l

            this.notifyDataSetChanged()
        }

        override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
            when (viewType) {
                VIEW_TYPE_SELECTED -> {
                    val view = LayoutInflater.from(parent.context)
                        .inflate(R.layout.selected_image, parent, false)
                    return MyVHSelected(view!!)
                }

                else -> {
                    var view =
                        LayoutInflater.from(parent.context).inflate(R.layout.image, parent, false)
                    return MyVHNormal(view!!)
                }
            }
        }

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

        override fun getItemViewType(position: Int): Int {
            var type = VIEW_TYPE_NORMAL
            if (items[position].selected) {
                type = VIEW_TYPE_SELECTED
            }

            return type
        }

        override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
            holder.itemView.setOnClickListener {
                items[position].selected = !items[position].selected

                this.notifyItemChanged(position)
            }

            val uri = items[position].path

            var siv: ShapeableImageView? = null
            when (getItemViewType(position)) {
                VIEW_TYPE_NORMAL -> {
                    siv = (holder as MyVHNormal).image
                }

                VIEW_TYPE_SELECTED -> {
                    siv = (holder as MyVHSelected).image
                }
            }

            Glide.with(holder.itemView.context)
                .asBitmap()
                .load(uri)
                .centerCrop()
                .override(IMAGE_SIZE)
                .into(siv!!)
        }
    }

    class MyVHNormal(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val image: ShapeableImageView = itemView.findViewById(R.id.siv)
    }

    class MyVHSelected(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val image: ShapeableImageView = itemView.findViewById(R.id.siv)
    }

    private fun readAllImage(context: Context): ArrayList {
        val photos = ArrayList()

        //读取所有图片
        val cursor = context.contentResolver.query(
            MediaStore.Images.Media.EXTERNAL_CONTENT_URI, null, null, null, null
        )

        var index = 0
        while (cursor!!.moveToNext()) {
            //路径 uri
            val path = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA))
            if (path.endsWith(".gif")) {
                //过滤gif图片。
                continue
            }

            //图片名称
            //val name = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DISPLAY_NAME))

            //图片大小
            //val size = cursor.getLong(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.SIZE))

            photos.add(MyData(path, index++))
        }
        cursor.close()

        return photos
    }

    class MyData(var path: String, var index: Int) {
        var selected = false
    }
}

image.xml：

selected_image.xml

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