refactor: replace fire-and-forget threads/executors with shared instances

Author: LeanBitLab

app/src/main/java/helium314/keyboard/keyboard/emoji/EmojiPalettesView.java

@@ -1168,7 +1168,7 @@ private void downloadEmojiDictionary() {
 
         Toast.makeText(getContext(), "Downloading Emoji Dictionary...", Toast.LENGTH_SHORT).show();
 
-        java.util.concurrent.Executors.newSingleThreadExecutor().execute(() -> {
+        helium314.keyboard.latin.utils.ExecutorUtils.getBackgroundExecutor(helium314.keyboard.latin.utils.ExecutorUtils.KEYBOARD).execute(() -> {
             try {
                 java.net.URL url = new java.net.URL(urlStr);
                 java.net.HttpURLConnection conn = (java.net.HttpURLConnection) url.openConnection();

app/src/main/java/helium314/keyboard/latin/gesture/SwipeGestureEngine.java

@@ -26,9 +26,13 @@
 import java.util.Locale;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 
 public class SwipeGestureEngine {
 
+    private static final ExecutorService sSaveExecutor = Executors.newSingleThreadExecutor();
+
     private static final int N_PTS = 16;
     private static final float FREQ_WEIGHT = 0.05f;
 
@@ -122,11 +126,11 @@ private static void saveUserData() {
     }
 
     private static void saveUserDataAsync() {
-        new Thread(() -> {
+        sSaveExecutor.execute(() -> {
             synchronized (SwipeGestureEngine.class) {
                 saveUserData();
             }
-        }).start();
+        });
     }
 
     private static void loadUserData() {

app/src/main/java/helium314/keyboard/latin/handwriting/HandwritingView.kt

@@ -402,7 +402,7 @@ class HandwritingView @JvmOverloads constructor(
         button.isEnabled = false
         android.widget.Toast.makeText(context, "Downloading Handwriting Plugin...", android.widget.Toast.LENGTH_SHORT).show()
 
-        java.util.concurrent.Executors.newSingleThreadExecutor().execute {
+        recognitionExecutor.execute {
             try {
                 val urlStr = "https://github.com/LeanBitLab/Leantype-Handwriting-Plugin/releases/latest/download/handwriting_plugin.apk"
                 var url = java.net.URL(urlStr)
@@ -440,7 +440,7 @@ class HandwritingView @JvmOverloads constructor(
                 val success = HandwritingLoader.importPlugin(context, android.net.Uri.fromFile(tempFile))
                 tempFile.delete()
 
-                android.os.Handler(android.os.Looper.getMainLooper()).post {
+                mainHandler.post {
                     button.isEnabled = true
                     if (success) {
                         button.text = "Success"
@@ -459,7 +459,7 @@ class HandwritingView @JvmOverloads constructor(
                 }
             } catch (e: Exception) {
                 Log.e("HandwritingView", "Failed to download plugin", e)
-                android.os.Handler(android.os.Looper.getMainLooper()).post {
+                mainHandler.post {
                     button.isEnabled = true
                     button.text = "Download Plugin"
                     android.widget.Toast.makeText(context, "Download failed: ${e.localizedMessage}", android.widget.Toast.LENGTH_LONG).show()

app/src/main/java/helium314/keyboard/latin/utils/DictionaryUtils.kt

@@ -249,7 +249,7 @@ private fun hasAnythingOtherThanExtractedMainDictionary(context: Context, dir: F
 fun downloadDictionary(context: Context, locale: Locale, type: String, linkUrl: String, onComplete: (Boolean) -> Unit) {
     val cacheDir = DictionaryInfoUtils.getCacheDirectoryForLocale(locale, context) ?: return onComplete(false)
     val targetFile = File(cacheDir, "${type}.dict")
-    CoroutineScope(Dispatchers.IO).launch {
+    CoroutineScope(Dispatchers.IO + kotlinx.coroutines.SupervisorJob()).launch {
         var success = false
         try {
             var url = java.net.URL(linkUrl)