Android LoaderManager CursorLoader load all photo to GridLayoutManager RecyclerView，kotlin

向右看齐 2023-09-26 22:58 106阅读 0赞

kotlin，LoaderManager CursorLoader load all photo to GridLayoutManager RecyclerView

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
        <uses-permission android:name="android.permission.READ_MEDIA_IMAGES" />

import android.database.Cursor
    import android.os.Bundle
    import android.provider.MediaStore
    import android.util.Log
    import androidx.appcompat.app.AppCompatActivity
    import androidx.loader.app.LoaderManager
    import androidx.loader.content.CursorLoader
    import androidx.loader.content.Loader
    import androidx.recyclerview.widget.GridLayoutManager
    import androidx.recyclerview.widget.RecyclerView
    import java.text.SimpleDateFormat
    import java.util.Date
    import kotlin.system.measureTimeMillis
    
    
    class MainActivity : AppCompatActivity() {
        private val TAG = "fly"
        private var loaderManager: LoaderManager? = null
        private var photoAdapter: PhotoAdapter? = null
        private val LOADER_ID = 2023
    
        override fun onCreate(savedInstanceState: Bundle?) {
            super.onCreate(savedInstanceState)
            setContentView(R.layout.activity_main)
    
            Log.d(TAG, "${getFormatTime()} onCreate ${Thread.currentThread().id}")
    
            val recyclerView: RecyclerView = findViewById(R.id.recyclerview)
            val layoutManager = GridLayoutManager(this, 5)
            recyclerView.setLayoutManager(layoutManager)
            photoAdapter = PhotoAdapter(this)
            recyclerView.setAdapter(photoAdapter)
    
            setupLoader()
        }
    
        override fun onRestart() {
            super.onRestart()
            //loaderManager?.getLoader<CursorLoader>(LOADER_ID)?.forceLoad()
        }
    
        override fun onDestroy() {
            super.onDestroy()
            loaderManager?.destroyLoader(LOADER_ID)
        }
    
        fun getFormatTime(): String {
            val sdf = SimpleDateFormat("MM-dd hh:mm:ss")
            val date: String = sdf.format(Date(System.currentTimeMillis()))
            return date
        }
    
        private fun getImages(cursor: Cursor?): List<Photo?>? {
            Log.d(TAG, "总量:${cursor?.count}")
            val photos: ArrayList<Photo> = ArrayList()
            Log.d(TAG, "Cursor start ${Thread.currentThread().id}")
    
            //读取手机图片
            //Cursor cursor = context.getContentResolver().query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, null, null, null, null);
            while (cursor?.moveToNext() == true) {
                //图片的路径
                val path: String =
                    cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA))
    
                //图片名称
                val name: String =
                    cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DISPLAY_NAME))
    
                //图片最后修改日期
                val date_modified =
                    cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATE_MODIFIED))
    
                val date: String =
                    SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(Date(date_modified.toLong()))
    
                //图片大小
                val size: Long =
                    cursor.getLong(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.SIZE))
    
                val photo = Photo(name, date, size, path, 0)
    
                photos.add(photo)
            }
    
            Log.d(TAG, "Cursor end ${Thread.currentThread().id}")
            cursor?.close()
    
            return photos
        }
    
        private fun setupLoader() {
            loaderManager = LoaderManager.getInstance(this)
            loaderManager?.initLoader(LOADER_ID, Bundle(), loaderCallbacks)
        }
    
        private val loaderCallbacks: LoaderManager.LoaderCallbacks<Cursor> =
            object : LoaderManager.LoaderCallbacks<Cursor> {
                override fun onCreateLoader(id: Int, args: Bundle?): Loader<Cursor> {
                    Log.d(TAG, "${getFormatTime()}  onCreateLoader ${Thread.currentThread().id}")
                    val loader = CursorLoader(applicationContext)
                    loader.uri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI
                    return loader
                }
    
                override fun onLoaderReset(loader: Loader<Cursor?>) {
    
                }
    
                override fun onLoadFinished(loader: Loader<Cursor?>, cursor: Cursor?) {
                    Log.d(TAG, "onLoadFinished in ${Thread.currentThread().id}")
    
                    var lists: ArrayList<Photo>
                    val time = measureTimeMillis {
                        lists = getImages(cursor) as ArrayList<Photo>
                    }
                    Log.d(TAG, "Cursor遍历耗时:$time")
    
                    photoAdapter?.dataChanged(lists)
    
                    Log.d(TAG, "onLoadFinished out ${Thread.currentThread().id}")
                }
            }
    }

import android.content.Context
    import android.view.LayoutInflater
    import android.view.View
    import android.view.ViewGroup
    import androidx.recyclerview.widget.RecyclerView
    import com.bumptech.glide.Glide
    import java.io.File
    
    
    class PhotoAdapter(private val context: Context) :
        RecyclerView.Adapter<PhotoHolder>() {
        private var items: ArrayList<Photo> = ArrayList()
    
        fun dataChanged(photos: ArrayList<Photo>) {
            this.items = photos
            notifyDataSetChanged()
        }
    
        override fun onCreateViewHolder(
            parent: ViewGroup,
            viewType: Int
        ): PhotoHolder {
            val view: View =
                LayoutInflater.from(parent.context).inflate(R.layout.item, parent, false)
            return PhotoHolder(view)
        }
    
    
        override fun onBindViewHolder(holder: PhotoHolder, pos: Int) {
            Glide.with(context).load(File(items[pos].path)).into(holder.image)
            holder.text.setText(items[pos].date)
            holder.pos.setText(pos.toString())
        }
    
        override fun getItemCount(): Int {
            return items.size
        }
    }

import android.view.View
    import android.widget.ImageView
    import android.widget.TextView
    
    import androidx.recyclerview.widget.RecyclerView
    
    class PhotoHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        var image: ImageView
        var text: TextView
        var pos: TextView
    
        init {
            image = itemView.findViewById(R.id.image)
            text = itemView.findViewById(R.id.text)
            pos = itemView.findViewById(R.id.pos)
        }
    }

class Photo(
        //名称
        var name: String,
    
        //日期
        var date: String,
    
        //大小
        var size: Long,
    
        //路径
        var path: String,
    
        var time: Long
    )

<?xml version="1.0" encoding="utf-8"?>
    <androidx.recyclerview.widget.RecyclerView xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/recyclerview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity"/>

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:padding="10dp">
    
        <ImageView
            android:id="@+id/image"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />
    
        <TextView
            android:id="@+id/text"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />
    
        <TextView
            android:id="@+id/pos"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />
    
    </LinearLayout>

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