Proper handling network unavailable error for images

app/src/main/kotlin/org/koitharu/kotatsu/core/util/ext/Throwable.kt

@@ -172,8 +172,9 @@ fun Throwable.getCauseUrl(): String? = when (this) {
 }
 
 private fun getHttpDisplayMessage(statusCode: Int, resources: Resources): String? = when (statusCode) {
-	404 -> resources.getString(R.string.not_found_404)
-	403 -> resources.getString(R.string.access_denied_403)
+	HttpURLConnection.HTTP_NOT_FOUND -> resources.getString(R.string.not_found_404)
+	HttpURLConnection.HTTP_FORBIDDEN -> resources.getString(R.string.access_denied_403)
+	HttpURLConnection.HTTP_GATEWAY_TIMEOUT -> resources.getString(R.string.network_unavailable)
 	in 500..599 -> resources.getString(R.string.server_error, statusCode)
 	else -> null
 }

app/src/main/kotlin/org/koitharu/kotatsu/image/ui/CoverImageView.kt

@@ -1,13 +1,16 @@
 package org.koitharu.kotatsu.image.ui
 
 import android.content.Context
+import android.graphics.drawable.LayerDrawable
 import android.os.Build
 import android.util.AttributeSet
+import android.view.Gravity
 import android.view.ViewGroup
 import android.view.ViewTreeObserver
 import android.view.ViewTreeObserver.OnPreDrawListener
 import androidx.annotation.AttrRes
 import androidx.annotation.RequiresApi
+import androidx.core.content.ContextCompat
 import androidx.core.content.withStyledAttributes
 import androidx.core.graphics.ColorUtils
 import androidx.core.graphics.drawable.toDrawable
@@ -33,6 +36,7 @@ import org.koitharu.kotatsu.core.ui.image.TrimTransformation
 import org.koitharu.kotatsu.core.util.ext.bookmarkExtra
 import org.koitharu.kotatsu.core.util.ext.decodeRegion
 import org.koitharu.kotatsu.core.util.ext.getThemeColor
+import org.koitharu.kotatsu.core.util.ext.isNetworkError
 import org.koitharu.kotatsu.core.util.ext.mangaExtra
 import org.koitharu.kotatsu.core.util.ext.mangaSourceExtra
 import org.koitharu.kotatsu.favourites.domain.model.Cover
@@ -185,10 +189,19 @@ class CoverImageView @JvmOverloads constructor(
 
 		override fun onError(request: ImageRequest, result: ErrorResult) {
 			super.onError(request, result)
-			foreground = result.throwable.getShortMessage()?.let { text ->
+			foreground = if (result.throwable.isNetworkError()) {
+				ContextCompat.getDrawable(context, R.drawable.ic_offline)?.let {
+					LayerDrawable(arrayOf(it)).apply {
+						setLayerGravity(0, Gravity.CENTER)
+						setTint(ContextCompat.getColor(context, R.color.dim_lite))
+					}
+				}
+			} else {
+				result.throwable.getShortMessage()?.let { text ->
 					TextDrawable.create(context, text, materialR.attr.textAppearanceTitleSmall)
 				}
 			}
+		}
 
 		private fun Throwable.getShortMessage(): String? = when (this) {
 			is HttpException -> response.code.toString()

app/src/main/res/drawable/ic_offline.xml

@@ -0,0 +1,11 @@
+<vector
+	xmlns:android="http://schemas.android.com/apk/res/android"
+	android:width="24dp"
+	android:height="24dp"
+	android:tint="?attr/colorControlNormal"
+	android:viewportWidth="24.0"
+	android:viewportHeight="24.0">
+	<path
+		android:fillColor="#000000"
+		android:pathData="M2.28,3L1,4.27L2.47,5.74C2.04,6 1.61,6.29 1.2,6.6L3,9C3.53,8.6 4.08,8.25 4.66,7.93L6.89,10.16C6.15,10.5 5.44,10.91 4.8,11.4L6.6,13.8C7.38,13.22 8.26,12.77 9.2,12.47L11.75,15C10.5,15.07 9.34,15.5 8.4,16.2L12,21L14.46,17.73L17.74,21L19,19.72M12,3C9.85,3 7.8,3.38 5.9,4.07L8.29,6.47C9.5,6.16 10.72,6 12,6C15.38,6 18.5,7.11 21,9L22.8,6.6C19.79,4.34 16.06,3 12,3M12,9C11.62,9 11.25,9 10.88,9.05L14.07,12.25C15.29,12.53 16.43,13.07 17.4,13.8L19.2,11.4C17.2,9.89 14.7,9 12,9Z" />
+</vector>

app/src/main/res/values-night/colors.xml

@@ -11,6 +11,7 @@
 	<color name="common_yellow">#FFF176</color>
 	<color name="common_red">#E57373</color>
 	<color name="dim2">#C8000000</color>
+	<color name="dim_lite">#66FFFFFF</color>
 	<color name="nsfw_18">#BF360C</color>
 	<color name="nsfw_16">#FF6F00</color>
 

app/src/main/res/values/colors.xml

@@ -16,6 +16,7 @@
 	<color name="grey">#424242</color>
 	<color name="dim">#99000000</color>
 	<color name="dim2">#C8FFFFFF</color>
+	<color name="dim_lite">#66000000</color>
 	<color name="warning">#E65100</color>
 	<color name="launcher_background">#FFFFFF</color>
 	<color name="common_green">#388E3C</color>