Fix ConcurrentModificationException for detectors (#111)

* Fix concurrent modification exception for detectors

* Construct detectors with pre-defined detectors

* Add version to CHANGELOG.md

* Fix codestyle

* Convert CircleCI build job to GHA

* Remove release from GHA main.yml and fix circle.yml

Author: jush

.github/workflows/main.yml

@@ -0,0 +1,37 @@
+name: CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ '**' ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    container:
+      image: mbgl/android-sdk:latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Check code style
+        run: make checkstyle
+
+      - name: Run Lint
+        run: ./gradlew lint
+
+      - name: Run unit-test in Android libraries
+        run: make test
+
+      - name: Upload reports
+        uses: actions/upload-artifact@v4
+        with:
+          name: reports
+          path: app/build/reports
+
+      - name: Upload test results
+        uses: actions/upload-artifact@v4
+        with:
+          name: test-results
+          path: app/build/test-results

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Changelog for the Mapbox Gestures for Android
 
+## 0.9.2 - September 29, 2025
+* Fix concurrent modification exception for detectors
+
 ## 0.9.1 - November 27, 2023
 Minor release with internal fixes for publishing library
 

build.gradle

@@ -5,13 +5,6 @@ buildscript {
         mavenCentral()
         maven {
             url 'https://api.mapbox.com/downloads/v2/releases/maven'
-            authentication {
-                basic(BasicAuthentication)
-            }
-            credentials {
-                username = "mapbox"
-                password = System.getenv("SDK_REGISTRY_TOKEN") ?: project.property("SDK_REGISTRY_TOKEN") as String
-            }
         }
     }
     dependencies {
@@ -28,13 +21,6 @@ allprojects {
         mavenCentral()
         maven {
             url 'https://api.mapbox.com/downloads/v2/releases/maven'
-            authentication {
-                basic(BasicAuthentication)
-            }
-            credentials {
-                username = "mapbox"
-                password = password = System.getenv("SDK_REGISTRY_TOKEN") ?: project.property("SDK_REGISTRY_TOKEN") as String
-            }
         }
     }
 }

circle.yml

@@ -4,7 +4,6 @@ workflows:
   version: 2
   default:
     jobs:
-      - build
       - release:
           filters:
             branches:
@@ -13,39 +12,6 @@ workflows:
               only: /^v.*/
 
 jobs:
-  build:
-    working_directory: ~/code
-    docker:
-      - image: mbgl/android-ndk-r21e:latest
-    environment:
-      JVM_OPTS: -Xmx3200m
-    steps:
-      - checkout
-      - restore_cache:
-          key: jars-{{ checksum "build.gradle" }}-{{ checksum  "app/build.gradle" }}-{{ checksum  "library/build.gradle" }}-{{ checksum  "gradle/dependencies.gradle" }}
-      - run:
-          name: Download Dependencies
-          command: ./gradlew androidDependencies
-      - save_cache:
-          paths:
-            - ~/.gradle
-          key: jars-{{ checksum "build.gradle" }}-{{ checksum  "app/build.gradle" }}-{{ checksum  "library/build.gradle" }}-{{ checksum  "gradle/dependencies.gradle" }}
-      - run:
-          name: Check code style
-          command: make checkstyle
-      - run:
-          name: Run Lint
-          command: ./gradlew lint
-      - run:
-          name: Run unit-test in Android libraries
-          command: make test
-      - store_artifacts:
-          path: app/build/reports
-          destination: reports
-      - store_test_results:
-          path: app/build/test-results
-
-# ------------------------------------------------------------------------------
   release:
     docker:
       - image: mbgl/android-ndk-r21e:latest

library/src/main/java/com/mapbox/android/gestures/AndroidGesturesManager.java

@@ -12,6 +12,7 @@
 import java.util.Arrays;
 import java.util.List;
 import java.util.Set;
+import java.util.concurrent.CopyOnWriteArrayList;
 
 /**
  * Entry point for all of the detectors. Set listener for gestures you'd like to be notified about
@@ -58,7 +59,7 @@ public class AndroidGesturesManager {
   public static final int GESTURE_TYPE_QUICK_SCALE = 15;
 
   private final List<Set<Integer>> mutuallyExclusiveGestures = new ArrayList<>();
-  private final List<BaseGesture> detectors = new ArrayList<>();
+  private final List<BaseGesture> detectors;
 
   private final StandardGestureDetector standardGestureDetector;
   private final StandardScaleGestureDetector standardScaleGestureDetector;
@@ -128,13 +129,15 @@ public AndroidGesturesManager(Context context, List<Set<Integer>> exclusiveGestu
     moveGestureDetector = new MoveGestureDetector(context, this);
     standardGestureDetector = new StandardGestureDetector(context, this);
 
-    detectors.add(rotateGestureDetector);
-    detectors.add(standardScaleGestureDetector);
-    detectors.add(shoveGestureDetector);
-    detectors.add(sidewaysShoveGestureDetector);
-    detectors.add(multiFingerTapGestureDetector);
-    detectors.add(moveGestureDetector);
-    detectors.add(standardGestureDetector);
+    detectors = new CopyOnWriteArrayList<BaseGesture>(Arrays.asList(
+            rotateGestureDetector,
+            standardScaleGestureDetector,
+            shoveGestureDetector,
+            sidewaysShoveGestureDetector,
+            multiFingerTapGestureDetector,
+            moveGestureDetector,
+            standardGestureDetector
+    ));
 
     if (applyDefaultThresholds) {
       initDefaultThresholds();

library/src/test/java/com/mapbox/android/gestures/AndroidGesturesManagerTest.java

@@ -1,5 +1,11 @@
 package com.mapbox.android.gestures;
 
+import static junit.framework.Assert.assertEquals;
+import static junit.framework.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import android.view.MotionEvent;
+
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -11,9 +17,6 @@
 import java.util.List;
 import java.util.Set;
 
-import static junit.framework.Assert.assertEquals;
-import static junit.framework.Assert.assertNotNull;
-
 @RunWith(RobolectricTestRunner.class)
 public class AndroidGesturesManagerTest {
   private AndroidGesturesManager androidGesturesManager;
@@ -44,9 +47,9 @@ public void setUp() throws Exception {
     mutuallyExclusivesList.add(set3);
 
     androidGesturesManager =
-      new AndroidGesturesManager(
-        RuntimeEnvironment.application.getApplicationContext(),
-        mutuallyExclusivesList, true);
+            new AndroidGesturesManager(
+                    RuntimeEnvironment.application.getApplicationContext(),
+                    mutuallyExclusivesList, true);
   }
 
   @Test
@@ -69,4 +72,24 @@ public void setMutuallyExclusivesTest() throws Exception {
     androidGesturesManager.setMutuallyExclusiveGestures(mutuallyExclusivesList);
     assertEquals(androidGesturesManager.getMutuallyExclusiveGestures(), mutuallyExclusivesList);
   }
+
+  @Test
+  public void onSingleTapModifyDetectorsTest() {
+    final StandardGestureDetector standardGestureDetector = new StandardGestureDetector(
+            RuntimeEnvironment.getApplication().getApplicationContext(),
+            androidGesturesManager
+    );
+
+    androidGesturesManager.setStandardGestureListener(new StandardGestureDetector.SimpleStandardOnGestureListener() {
+      @Override
+      public boolean onDown(MotionEvent e) {
+        androidGesturesManager.getDetectors().add(standardGestureDetector);
+        return true;
+      }
+    });
+
+    MotionEvent downEvent = TestUtils.INSTANCE.getMotionEvent(MotionEvent.ACTION_DOWN, 0, 0, null);
+    androidGesturesManager.onTouchEvent(downEvent);
+    assertTrue(androidGesturesManager.getDetectors().contains(standardGestureDetector));
+  }
 }