Modify result response protocol

shell/platform/android/io/flutter/embedding/engine/systemchannels/SpellCheckChannel.java

@@ -11,7 +11,6 @@
 import io.flutter.plugin.common.JSONMethodCodec;
 import io.flutter.plugin.common.MethodCall;
 import io.flutter.plugin.common.MethodChannel;
-import java.util.ArrayList;
 import org.json.JSONArray;
 import org.json.JSONException;
 
@@ -44,9 +43,6 @@ public class SpellCheckChannel {
   public final MethodChannel channel;
   private SpellCheckMethodHandler spellCheckMethodHandler;
 
-  private String textAwaitingResponse;
-  private MethodChannel.Result resultAwaitingResponse;
-
   @NonNull
   final MethodChannel.MethodCallHandler parsingMethodHandler =
       new MethodChannel.MethodCallHandler() {
@@ -67,10 +63,8 @@ public void onMethodCall(@NonNull MethodCall call, @NonNull MethodChannel.Result
                 final JSONArray argumentList = (JSONArray) args;
                 String locale = argumentList.getString(0);
                 String text = argumentList.getString(1);
-                textAwaitingResponse = text;
-                resultAwaitingResponse = result;
 
-                spellCheckMethodHandler.initiateSpellCheck(locale, text);
+                spellCheckMethodHandler.initiateSpellCheck(locale, text, result);
               } catch (JSONException exception) {
                 result.error("error", exception.getMessage(), null);
               }
@@ -87,18 +81,6 @@ public SpellCheckChannel(@NonNull DartExecutor dartExecutor) {
     channel.setMethodCallHandler(parsingMethodHandler);
   }
 
-  /** Responsible for sending spell check results and corresponding text through this channel. */
-  public void updateSpellCheckResults(ArrayList<String> spellCheckResults) {
-    spellCheckResults.add(0, textAwaitingResponse);
-
-    if (resultAwaitingResponse != null && textAwaitingResponse != null) {
-      resultAwaitingResponse.success(spellCheckResults);
-    }
-
-    resultAwaitingResponse = null;
-    textAwaitingResponse = null;
-  }
-
   /**
    * Sets the {@link SpellCheckMethodHandler} which receives all requests to spell check the
    * specified text sent through this channel.
@@ -110,11 +92,11 @@ public void setSpellCheckMethodHandler(
 
   public interface SpellCheckMethodHandler {
     /**
-     * Requests that spell check is initiated for the specified text, which will automatically
-     * result in a call to {@code
-     * SpellCheckChannel#setSpellCheckMethodHandler(SpellCheckMethodHandler)} once spell check
-     * results are received from the native spell check service.
+     * Requests that spell check is initiated for the specified text, which will respond to the
+     * {@code result} with either success if spell check results are received or error if the
+     * request is skipped.
      */
-    void initiateSpellCheck(@NonNull String locale, @NonNull String text);
+    void initiateSpellCheck(
+        @NonNull String locale, @NonNull String text, @NonNull MethodChannel.Result result);
   }
 }

shell/platform/android/io/flutter/plugin/editing/SpellCheckPlugin.java

@@ -11,8 +11,10 @@
 import android.view.textservice.TextServicesManager;
 import androidx.annotation.NonNull;
 import io.flutter.embedding.engine.systemchannels.SpellCheckChannel;
+import io.flutter.plugin.common.MethodChannel;
 import io.flutter.plugin.localization.LocalizationPlugin;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Locale;
 
 /**
@@ -32,9 +34,11 @@ public class SpellCheckPlugin
   private final TextServicesManager mTextServicesManager;
   private SpellCheckerSession mSpellCheckerSession;
 
+  private MethodChannel.Result pendingResult;
+  private String pendingResultText;
+
   // The maximum number of suggestions that the Android spell check service is allowed to provide
-  // per word.
-  // Same number that is used by default for Android's TextViews.
+  // per word. Same number that is used by default for Android's TextViews.
   private static final int MAX_SPELL_CHECK_SUGGESTIONS = 5;
 
   public SpellCheckPlugin(
@@ -62,8 +66,21 @@ public void destroy() {
     }
   }
 
+  /**
+   * Initiates call to native spell checker to spell check specified text if there is no result
+   * awaiting a response.
+   */
   @Override
-  public void initiateSpellCheck(@NonNull String locale, @NonNull String text) {
+  public void initiateSpellCheck(
+      @NonNull String locale, @NonNull String text, @NonNull MethodChannel.Result result) {
+    if (pendingResult != null) {
+      result.error("error", "Previous spell check request still pending.", null);
+      return;
+    }
+
+    pendingResult = result;
+    pendingResultText = text;
+
     performSpellCheck(locale, text);
   }
 
@@ -96,13 +113,13 @@ public void performSpellCheck(@NonNull String locale, @NonNull String text) {
    */
   @Override
   public void onGetSentenceSuggestions(SentenceSuggestionsInfo[] results) {
-    ArrayList<String> spellCheckerSuggestionSpans = new ArrayList<String>();
-
     if (results.length == 0) {
-      mSpellCheckChannel.updateSpellCheckResults(spellCheckerSuggestionSpans);
+      pendingResult.success(new ArrayList<>(Arrays.asList(pendingResultText, "")));
+      pendingResult = null;
       return;
     }
 
+    ArrayList<String> spellCheckerSuggestionSpans = new ArrayList<String>();
     SentenceSuggestionsInfo spellCheckResults = results[0];
 
     for (int i = 0; i < spellCheckResults.getSuggestionsCount(); i++) {
@@ -128,7 +145,9 @@ public void onGetSentenceSuggestions(SentenceSuggestionsInfo[] results) {
           spellCheckerSuggestionSpan.substring(0, spellCheckerSuggestionSpan.length() - 1));
     }
 
-    mSpellCheckChannel.updateSpellCheckResults(spellCheckerSuggestionSpans);
+    spellCheckerSuggestionSpans.add(0, pendingResultText);
+    pendingResult.success(spellCheckerSuggestionSpans);
+    pendingResult = null;
   }
 
   @Override