Adjust thread pool priority

Readme.md

@@ -1,4 +1,4 @@
-[ ![Download](https://api.bintray.com/packages/peterlaurence/maven/mapview/images/download.svg?version=1.0.6) ](https://bintray.com/peterlaurence/maven/mapview/1.0.6/link)
+[ ![Download](https://api.bintray.com/packages/peterlaurence/maven/mapview/images/download.svg?version=1.0.7) ](https://bintray.com/peterlaurence/maven/mapview/1.0.7/link)
 
 # MapView
 
@@ -29,7 +29,7 @@ This project holds the source code of this library, plus a demo app (which is us
 
 Add this to your module's build.gradle
 ```groovy
-implementation 'com.peterlaurence:mapview:1.0.6'
+implementation 'com.peterlaurence:mapview:1.0.7'
 ```
 
 ## Origin and motivation

demo/build.gradle

@@ -4,11 +4,11 @@ apply plugin: 'kotlin-android-extensions'
 apply plugin: 'kotlinx-serialization'
 
 android {
-    compileSdkVersion 28
+    compileSdkVersion 29
     defaultConfig {
         applicationId "com.peterlaurence.mapview.demo"
         minSdkVersion 23
-        targetSdkVersion 28
+        targetSdkVersion 29
         versionCode 1
         versionName "1.0"
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"

mapview/build.gradle

@@ -4,7 +4,7 @@ apply plugin: 'kotlin-android'
 apply plugin: 'kotlin-android-extensions'
 apply plugin: 'kotlinx-serialization'
 
-def version = "1.0.6"
+def version = "1.0.7"
 
 androidExtensions {
     experimental = true
@@ -20,12 +20,12 @@ buildscript {
 }
 
 android {
-    compileSdkVersion 28
+    compileSdkVersion 29
 
 
     defaultConfig {
         minSdkVersion 23
-        targetSdkVersion 28
+        targetSdkVersion 29
         versionCode 2
         versionName version
     }
@@ -54,7 +54,7 @@ dependencies {
 
     implementation 'androidx.appcompat:appcompat:1.1.0'
     testImplementation 'junit:junit:4.12'
-    testImplementation 'org.robolectric:robolectric:4.3'
+    testImplementation 'org.robolectric:robolectric:4.3.1'
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
     implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.2'
     implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.2'

mapview/src/main/java/com/peterlaurence/mapview/core/TileCollector.kt

@@ -136,8 +136,10 @@ class TileCollector(private val workerCount: Int) {
             SynchronousQueue<Runnable>(), ThreadFactory { r ->
         Thread(r).apply {
             isDaemon = true
-            priority = Thread.MIN_PRIORITY
-            Process.setThreadPriority(Process.THREAD_PRIORITY_LOWEST)
+            /* Beware, using THREAD_PRIORITY_LOWEST leads to UI hang on some emulators, while
+             * THREAD_PRIORITY_BACKGROUND has similar positive impact on overall responsiveness on
+             * low-end devices while not having this side effect. */
+            Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND)
         }
     }).asCoroutineDispatcher()
 }

mapview/src/test/java/com/peterlaurence/mapview/core/TileCollectorTest.kt

@@ -2,6 +2,7 @@ package com.peterlaurence.mapview.core
 
 import android.graphics.Bitmap
 import android.graphics.BitmapFactory
+import android.os.Build
 import kotlinx.coroutines.*
 import kotlinx.coroutines.channels.Channel
 import kotlinx.coroutines.channels.ReceiveChannel
@@ -13,6 +14,7 @@ import org.junit.Assert.*
 import org.junit.Test
 import org.junit.runner.RunWith
 import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
 import java.io.File
 import java.io.FileInputStream
 import java.io.InputStream
@@ -26,6 +28,7 @@ import com.peterlaurence.mapview.core.TileStreamProvider as MapViewTileStreamPro
  * * The [Bitmap] of the [Tile]s produced should be consistent with the output of the flow
  */
 @RunWith(RobolectricTestRunner::class)
+@Config(sdk = [Build.VERSION_CODES.P])
 class TileCollectorTest {
 
     private val tileSize = 256