Android Coil3 Fetcher preload批量Bitmap拼接扁平宽图，Kotlin
在这一篇文章基础上改进：
XML
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_MEDIA_IMAGES" />
<uses-permission android:name="android.permission.READ_MEDIA_VIDEO" />
XML
implementation("io.coil-kt.coil3:coil:3.1.0")
implementation("io.coil-kt.coil3:coil-gif:3.1.0")
implementation("io.coil-kt.coil3:coil-core:3.1.0")
Kotlin
import android.content.ContentUris
import android.content.Context
import android.net.Uri
import android.os.Bundle
import android.provider.MediaStore
import android.util.Log
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.lifecycleScope
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import coil3.ImageLoader
import coil3.memory.MemoryCache
import coil3.request.ImageRequest
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch
class MainActivity : AppCompatActivity() {
companion object {
const val THUMB_WIDTH = 150
const val THUMB_HEIGHT = 150
const val ROW_SIZE = 16
const val TAG = "fly/MainActivity"
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val rv = findViewById<RecyclerView>(R.id.rv)
val layoutManager = LinearLayoutManager(this)
layoutManager.orientation = LinearLayoutManager.VERTICAL
val imageLoader = MyCoilManager.INSTANCE.getImageLoader(applicationContext)
val adapter = MyAdapter(this, imageLoader)
rv.adapter = adapter
rv.layoutManager = layoutManager
rv.setItemViewCacheSize(ROW_SIZE)
rv.recycledViewPool.setMaxRecycledViews(0, ROW_SIZE)
val ctx = this
lifecycleScope.launch(Dispatchers.IO) {
val imgList = readAllImage(ctx)
val videoList = readAllVideo(ctx)
Log.d(TAG, "readAllImage size=${imgList.size}")
Log.d(TAG, "readAllVideo size=${videoList.size}")
val lists = arrayListOf<MyData>()
lists.addAll(imgList)
lists.addAll(videoList)
val total = lists.size
Log.d(TAG, "总数量=$total")
lists.shuffle()
val items = sliceDataList(lists)
lifecycleScope.launch(Dispatchers.Main) {
adapter.dataChanged(items)
}
val PRELOAD = true
if (PRELOAD) {
val probability = 0.85f
val from = 500
lists.forEachIndexed { idx, myData ->
if (idx > from && (Math.random() <= probability)) {
Log.d(TAG, "$idx/$total preload")
preload(imageLoader, myData)
}
}
}
}
}
private fun preload(imageLoader: ImageLoader, myData: MyData) {
val thumbItem = Item(uri = myData.uri, path = myData.path)
thumbItem.type = Item.THUMB
val thumbMemoryCacheKey = MemoryCache.Key(thumbItem.toString())
val thumbMemoryCache = MyCoilManager.INSTANCE.getMemoryCache(thumbMemoryCacheKey)
if (thumbMemoryCache == null) {
val thumbReq = ImageRequest.Builder(this)
.data(thumbItem)
.size(THUMB_WIDTH, THUMB_HEIGHT)
.memoryCacheKey(thumbMemoryCacheKey)
.build()
imageLoader.enqueue(thumbReq)
}
}
class MyData(var path: String, var uri: Uri)
private fun sliceDataList(data: ArrayList<MyData>): ArrayList<ArrayList<MyData>> {
var k: Int
val lists = ArrayList<ArrayList<MyData>>()
for (i in data.indices step ROW_SIZE) {
val temp = ArrayList<MyData>()
k = 0
for (j in 0 until ROW_SIZE) {
k = i + j
if (k >= data.size) {
break
}
temp.add(data[k])
}
lists.add(temp)
}
return lists
}
private fun readAllImage(ctx: Context): ArrayList<MyData> {
val photos = ArrayList<MyData>()
//读取所有图
val cursor = ctx.contentResolver.query(
MediaStore.Images.Media.EXTERNAL_CONTENT_URI, null, null, null, null
)
while (cursor!!.moveToNext()) {
//路径
val path = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA))
val id = cursor.getColumnIndex(MediaStore.Images.ImageColumns._ID)
val imageUri: Uri = ContentUris.withAppendedId(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, cursor.getLong(id))
//名称
//val name = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DISPLAY_NAME))
//大小
//val size = cursor.getLong(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.SIZE))
photos.add(MyData(path, imageUri))
}
cursor.close()
return photos
}
private fun readAllVideo(context: Context): ArrayList<MyData> {
val videos = ArrayList<MyData>()
//读取视频Video
val cursor = context.contentResolver.query(
MediaStore.Video.Media.EXTERNAL_CONTENT_URI,
null,
null,
null,
null
)
while (cursor!!.moveToNext()) {
//路径
val path = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.DATA))
val id = cursor.getColumnIndex(MediaStore.Images.ImageColumns._ID)
val videoUri: Uri = ContentUris.withAppendedId(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, cursor.getLong(id))
//名称
//val name = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.DISPLAY_NAME))
//大小
//val size = cursor.getLong(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.SIZE))
videos.add(MyData(path, videoUri))
}
cursor.close()
return videos
}
}
Kotlin
import android.net.Uri
class Item {
companion object {
const val THUMB = 0
const val IMG = 1
}
var uri: Uri? = null
var path: String? = null
var lastModified = 0L
var width = 0
var height = 0
var position = -1
var type = -1 //0,缩略图。 1，正图image。-1,未知。
constructor(uri: Uri, path: String) {
this.uri = uri
this.path = path
}
override fun toString(): String {
return "Item(uri=$uri, path=$path, lastModified=$lastModified, width=$width, height=$height, position=$position, type=$type)"
}
}
Kotlin
import android.content.Context
import android.view.View
import android.view.ViewGroup
import androidx.recyclerview.widget.RecyclerView
import coil3.ImageLoader
import com.appdemo.MainActivity.MyData
class MyAdapter : RecyclerView.Adapter<MyAdapter.ImageHolder> {
private var mCtx: Context? = null
private var mImageLoader: ImageLoader? = null
private var mItems = ArrayList<ArrayList<MyData>>()
private var mScreenWidth = 0
companion object {
const val TAG = "fly/ImageAdapter"
}
constructor(ctx: Context, il: ImageLoader?) : super() {
mCtx = ctx
mScreenWidth = mCtx?.resources?.displayMetrics?.widthPixels!!
mImageLoader = il
}
fun dataChanged(items: ArrayList<ArrayList<MyData>>) {
this.mItems = items
notifyDataSetChanged()
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ImageHolder {
val view = MyImgView(mCtx!!, mImageLoader, mScreenWidth)
return ImageHolder(view)
}
override fun onBindViewHolder(holder: ImageHolder, position: Int) {
holder.image.setData(mItems[position])
}
override fun getItemCount(): Int {
return mItems.size
}
class ImageHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
var image = itemView as MyImgView
}
}
Kotlin
import android.app.Application
import android.util.Log
import coil3.ImageLoader
import coil3.PlatformContext
import coil3.SingletonImageLoader
class MyApp : Application(), SingletonImageLoader.Factory {
companion object {
const val TAG = "fly/MyApp"
}
override fun newImageLoader(context: PlatformContext): ImageLoader {
Log.d(TAG, "newImageLoader")
return MyCoilManager.INSTANCE.getImageLoader(this)
}
}
Kotlin
import android.content.Context
import android.os.Environment
import android.util.Log
import coil3.ImageLoader
import coil3.disk.DiskCache
import coil3.disk.directory
import coil3.gif.AnimatedImageDecoder
import coil3.memory.MemoryCache
import coil3.request.CachePolicy
import java.io.File
class MyCoilManager {
companion object {
const val TAG = "fly/MyCoilManager"
val INSTANCE by lazy(mode = LazyThreadSafetyMode.SYNCHRONIZED) { MyCoilManager() }
}
private var mImageLoader: ImageLoader? = null
private var memoryCacheMaxSize = 0L
fun getImageLoader(ctx: Context): ImageLoader {
if (mImageLoader != null) {
Log.w(TAG, "ImageLoader已经初始化")
return mImageLoader!!
}
Log.d(TAG, "初始化ImageLoader")
//初始化加载器。
mImageLoader = ImageLoader.Builder(ctx)
.memoryCachePolicy(CachePolicy.ENABLED)
.memoryCache(initMemoryCache())
.diskCachePolicy(CachePolicy.ENABLED)
.diskCache(initDiskCache())
.components {
add(AnimatedImageDecoder.Factory())
add(ThumbFetcher.Factory(ctx))
}.build()
Log.d(TAG, "memoryCache.maxSize=${mImageLoader!!.memoryCache?.maxSize}")
return mImageLoader!!
}
private fun initMemoryCache(): MemoryCache {
//内存缓存。
val memoryCache = MemoryCache.Builder()
.maxSizeBytes(1024 * 1024 * 1024 * 2L) //2GB
.build()
memoryCacheMaxSize = memoryCache.maxSize
return memoryCache
}
private fun initDiskCache(): DiskCache {
//磁盘缓存。
val diskCacheFolder = Environment.getExternalStorageDirectory()
val diskCacheName = "coil_disk_cache"
val cacheFolder = File(diskCacheFolder, diskCacheName)
if (cacheFolder.exists()) {
Log.d(TAG, "${cacheFolder.absolutePath} exists")
} else {
if (cacheFolder.mkdir()) {
Log.d(TAG, "${cacheFolder.absolutePath} create OK")
} else {
Log.e(TAG, "${cacheFolder.absolutePath} create fail")
}
}
val diskCache = DiskCache.Builder()
.maxSizeBytes(1024 * 1024 * 1024 * 2L) //2GB
.directory(cacheFolder)
.build()
Log.d(TAG, "cache folder = ${diskCache.directory.toFile().absolutePath}")
return diskCache
}
fun getMemoryCache(key: MemoryCache.Key): MemoryCache.Value? {
return mImageLoader?.memoryCache?.get(key)
}
fun calMemoryCache(): String {
val sz = mImageLoader?.memoryCache?.size
return "${sz?.toFloat()!! / memoryCacheMaxSize.toFloat()} , $sz / $memoryCacheMaxSize"
}
}
Kotlin
import android.content.Context
import android.graphics.Bitmap
import android.graphics.Canvas
import android.graphics.Color
import android.graphics.Picture
import android.graphics.RectF
import android.util.Log
import androidx.appcompat.app.AppCompatActivity
import androidx.appcompat.widget.AppCompatImageView
import androidx.core.graphics.toRect
import androidx.lifecycle.lifecycleScope
import coil3.ImageLoader
import coil3.memory.MemoryCache
import coil3.request.ErrorResult
import coil3.request.ImageRequest
import coil3.request.SuccessResult
import coil3.toBitmap
import com.appdemo.MainActivity.MyData
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch
class MyImgView : AppCompatImageView {
companion object {
const val TAG = "fly/MyImgView"
//整数相除，精度损失的平衡因子
const val BALANCE_FACTOR = 1
}
private var mCtx: Context? = null
private var mImageLoader: ImageLoader? = null
private var mScreenWidth: Int = 0
private var mHeight: Int = 0
private var mRealSize: Int = 0
private var mBmp = mutableListOf<DataBean>()
constructor(ctx: Context, il: ImageLoader?, screenWidth: Int) : super(ctx) {
mCtx = ctx
mImageLoader = il
mScreenWidth = screenWidth
mHeight = mScreenWidth / MainActivity.ROW_SIZE + BALANCE_FACTOR
scaleType = ScaleType.CENTER_CROP
}
fun setData(data: ArrayList<MyData>) {
mRealSize = data.size
(mCtx as AppCompatActivity).lifecycleScope.launch(Dispatchers.IO) {
var loadCount = 0
// this for-loop will cost some time
// if no memory cache, for-loop more , time cost more
data.forEachIndexed { _, myData ->
val thumbItem = Item(uri = myData.uri, path = myData.path)
thumbItem.type = Item.THUMB
val thumbMemoryCacheKey = MemoryCache.Key(thumbItem.toString())
val thumbMemoryCache = MyCoilManager.INSTANCE.getMemoryCache(thumbMemoryCacheKey)
// be careful, this block will cost time
// time cost point
if (thumbMemoryCache == null) {
val t = System.currentTimeMillis()
val thumbReq = ImageRequest.Builder(mCtx!!)
.data(thumbItem)
.size(MainActivity.THUMB_WIDTH, MainActivity.THUMB_HEIGHT)
.memoryCacheKey(thumbMemoryCacheKey)
.listener(object : ImageRequest.Listener {
override fun onSuccess(request: ImageRequest, result: SuccessResult) {
loadCount++
refresh(loadCount, result.image.toBitmap())
}
override fun onCancel(request: ImageRequest) {
Log.w(TAG, "onCancel")
loadCount++
refresh(loadCount, null)
}
override fun onError(request: ImageRequest, result: ErrorResult) {
Log.e(TAG, "onError")
loadCount++
refresh(loadCount, null)
}
}).build()
mImageLoader?.enqueue(thumbReq)
Log.d(TAG, "加载... 耗时=${System.currentTimeMillis() - t}")
} else {
Log.d(TAG, "命中缓存 ${MyCoilManager.INSTANCE.calMemoryCache()}")
loadCount++
refresh(loadCount, thumbMemoryCache.image.toBitmap())
}
}
}
}
private fun refresh(loadCount: Int, bmp: Bitmap?) {
val bean = DataBean(bmp)
mBmp.add(bean)
if (loadCount == mRealSize) {
val jBmp = joinBitmap()
(mCtx as AppCompatActivity).lifecycleScope.launch(Dispatchers.Main) {
this@MyImgView.setImageBitmap(jBmp)
}
mBmp.clear()
}
}
data class DataBean(var bitmap: Bitmap?)
private fun joinBitmap(): Bitmap {
val bmp = Bitmap.createBitmap(mHeight * mRealSize, mHeight, Bitmap.Config.RGB_565)
val canvas = Canvas(bmp)
canvas.drawColor(Color.LTGRAY)
val bitmaps = mBmp.toMutableList()
bitmaps.forEachIndexed { idx, dataBean ->
if (dataBean.bitmap != null) {
if (Bitmap.Config.HARDWARE == dataBean.bitmap!!.config) {
Log.d(TAG, "Bitmap.Config.HARDWARE")
dataBean.bitmap = convert(dataBean.bitmap)
}
val w = dataBean.bitmap!!.width
val h = dataBean.bitmap!!.height
val mini = Math.min(w, h)
val left = (w - mini) / 2f
val top = (h - mini) / 2f
val right = (w + mini) / 2f
val bottom = (h + mini) / 2f
val srcRct = RectF(left, top, right, bottom)
val dstRctLeft = idx * mHeight.toFloat()
val dstRct = RectF(dstRctLeft, 0f, dstRctLeft + mHeight, mHeight.toFloat())
canvas.drawBitmap(dataBean.bitmap!!, srcRct.toRect(), dstRct.toRect(), null)
}
}
bitmaps.clear()
return bmp
}
private fun convert(src: Bitmap?): Bitmap {
val w = src?.width
val h = src?.height
val picture = Picture()
val canvas = picture.beginRecording(w!!, h!!)
canvas.drawBitmap(src, 0f, 0f, null)
picture.endRecording()
return Bitmap.createBitmap(picture, w, h, Bitmap.Config.RGB_565)
}
override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec)
if (mHeight == 0) {
setMeasuredDimension(mScreenWidth, MainActivity.THUMB_HEIGHT)
} else {
setMeasuredDimension(mHeight * mRealSize, mHeight)
}
}
}
Kotlin
import android.content.Context
import android.graphics.Bitmap
import android.util.Log
import android.util.Size
import coil3.ImageLoader
import coil3.asImage
import coil3.decode.DataSource
import coil3.fetch.FetchResult
import coil3.fetch.Fetcher
import coil3.fetch.ImageFetchResult
import coil3.request.Options
/**
* 例如 FileUriFetcher
*/
class ThumbFetcher(private val ctx: Context, private val thumbItem: Item, private val options: Options) : Fetcher {
companion object {
const val TAG = "fly/ThumbFetcher"
}
override suspend fun fetch(): FetchResult {
var bmp: Bitmap? = null
val t = System.currentTimeMillis()
try {
bmp = ctx.contentResolver.loadThumbnail(thumbItem.uri!!, Size(MainActivity.THUMB_WIDTH, MainActivity.THUMB_HEIGHT), null)
Log.d(TAG, "loadThumbnail time cost=${System.currentTimeMillis() - t} $thumbItem ${MyCoilManager.INSTANCE.calMemoryCache()}")
} catch (e: Exception) {
Log.e(TAG, "e=$e ThumbItem=$thumbItem")
}
return ImageFetchResult(
bmp?.asImage()!!,
true,
dataSource = DataSource.DISK
)
}
class Factory(private val ctx: Context) : Fetcher.Factory<Item> {
override fun create(
data: Item,
options: Options,
imageLoader: ImageLoader,
): Fetcher {
return ThumbFetcher(ctx, data, options)
}
}
}