Use android HttpResponseCache instead of an ugly implementation.

apng_library/src/main/java/oupson/apng/ApngAnimator.kt

@@ -274,20 +274,19 @@ class ApngAnimator(private val context: Context?) {
             this@ApngAnimator.speed = speed
             // Download PNG
             try {
-                Loader.load(context!!, url).apply {
+                Loader.load(url).apply {
                     try {
                         this@ApngAnimator.load(this, speed, apngAnimatorOptions)
                     } catch (e: NotPngException) {
                         if (loadNotApng) {
-                            val bytes = this.readBytes()
                             GlobalScope.launch(Dispatchers.Main) {
                                 imageView?.scaleType =
                                     this@ApngAnimator.scaleType ?: ImageView.ScaleType.FIT_CENTER
                                 imageView?.setImageBitmap(
                                     BitmapFactory.decodeByteArray(
-                                        bytes,
+                                        this@apply,
                                         0,
-                                        bytes.size
+                                        this@apply.size
                                     )
                                 )
                             }

apng_library/src/main/java/oupson/apng/Loader.kt

@@ -1,36 +1,30 @@
 package oupson.apng
 
-import android.content.Context
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
 import java.io.BufferedInputStream
-import java.io.File
+import java.io.ByteArrayOutputStream
-import java.io.FileOutputStream
 import java.io.IOException
+import java.net.HttpURLConnection
 import java.net.URL
 
 class Loader {
     companion object {
         /**
          * Download file from given url.
-         * @param context Context of app.
          * @param url Url of the file to download.
          * @return [ByteArray] of the file.
          */
-        @Throws(IOException::class, java.io.FileNotFoundException::class)
+        @Throws(IOException::class)
-        suspend fun load(context: Context, url: URL) =
+        suspend fun load(url: URL): ByteArray =
             withContext(Dispatchers.IO) {
-                val currentDir = context.filesDir
+                val connection = url.openConnection() as HttpURLConnection
-                val fileTXT = File(currentDir, "apngLoader.txt")
+                connection.useCaches = true
-                val filePNG = File(currentDir, "apngLoader.png")
+                connection.connect()
-                if (fileTXT.exists() && url.toString() == fileTXT.readText()) {
+                if (connection.responseCode == 200) {
-                    filePNG
+                    val input = BufferedInputStream(connection.inputStream)
-                } else {
+                    val output = ByteArrayOutputStream()
-                    val connection = url.openConnection()
+                    var bytesRead: Int
-                    connection.connect()
-                    val input = BufferedInputStream(connection.getInputStream())
-                    val output = FileOutputStream(filePNG)
-                    var bytesRead : Int
                     val buffer = ByteArray(4096)
                     do {
                         bytesRead = input.read(buffer)
@@ -39,8 +33,11 @@ class Loader {
                     } while (bytesRead != -1)
                     input.close()
                     output.close()
-                    fileTXT.writeText(url.toString())
+                    connection.disconnect()
-                    filePNG
+                    output.toByteArray()
+                } else {
+                    connection.disconnect()
+                    throw Exception("Error when downloading file : ${connection.responseCode}")
                 }
             }
     }

apng_library/src/main/java/oupson/apng/decoder/ApngDecoder.kt

@@ -24,10 +24,7 @@ import oupson.apng.exceptions.BadApng
 import oupson.apng.exceptions.BadCRC
 import oupson.apng.utils.Utils
 import oupson.apng.utils.Utils.Companion.isPng
-import java.io.BufferedInputStream
+import java.io.*
-import java.io.File
-import java.io.FileInputStream
-import java.io.InputStream
 import java.net.URL
 import java.nio.ByteBuffer
 import java.util.zip.CRC32
@@ -536,9 +533,7 @@ class ApngDecoder {
             withContext(Dispatchers.IO) {
                 decodeApng(
                     context,
-                    FileInputStream(
+                    ByteArrayInputStream(Loader.load(url)),
-                        Loader.load(context, url)
-                    ),
                     speed,
                     config
                 )
@@ -706,9 +701,8 @@ class ApngDecoder {
                     val drawable =
                         decodeApng(
                             context,
-                            FileInputStream(
+                            ByteArrayInputStream(
                                 Loader.load(
-                                    context,
                                     url
                                 )
                             ),

app-test/src/main/java/oupson/apngcreator/activities/MainActivity.kt

@@ -2,6 +2,7 @@ package oupson.apngcreator.activities
 
 import android.annotation.SuppressLint
 import android.content.Intent
+import android.net.http.HttpResponseCache
 import android.os.Bundle
 import android.view.MenuItem
 import androidx.appcompat.app.ActionBarDrawerToggle
@@ -17,6 +18,7 @@ import oupson.apngcreator.R
 import oupson.apngcreator.fragments.ApngDecoderFragment
 import oupson.apngcreator.fragments.JavaFragment
 import oupson.apngcreator.fragments.KotlinFragment
+import java.io.File
 
 
 class MainActivity : AppCompatActivity() {
@@ -30,11 +32,15 @@ class MainActivity : AppCompatActivity() {
 
         setContentView(R.layout.activity_main)
 
-
         setSupportActionBar(bottomAppBar)
 
         setUpBottomAppBarShapeAppearance()
 
+        val httpCacheSize = 10 * 1024 * 1024.toLong() // 10 MiB
+
+        val httpCacheDir = File(cacheDir, "http")
+        HttpResponseCache.install(httpCacheDir, httpCacheSize)
+
         fabCreate.setOnClickListener {
             startActivity(Intent(this, CreatorActivity::class.java))
         }
@@ -135,6 +141,11 @@ class MainActivity : AppCompatActivity() {
         }
     }
 
+    override fun onStop() {
+        super.onStop()
+        HttpResponseCache.getInstalled()?.flush()
+    }
+
     private fun setUpBottomAppBarShapeAppearance() {
         val fabShapeAppearanceModel: ShapeAppearanceModel = fabCreate.shapeAppearanceModel
         val cutCornersFab =