[android] #3891 - capture the callback by copy, avoid GC, and declare…

… a new JNIEnv
mapbox · Feb 19, 2016 · debcaa2 · debcaa2
1 parent 79f918e
commit debcaa2
Showing 1 changed file with 12 additions and 9 deletions.
diff --git a/platform/android/src/jni.cpp b/platform/android/src/jni.cpp
@@ -1720,36 +1720,39 @@ void JNICALL createOfflineRegion(JNIEnv *env, jobject obj, jlong defaultFileSour
     // Metadata
     mbgl::OfflineRegionMetadata metadata;
 
+    createCallback = reinterpret_cast<jobject>(env->NewGlobalRef(createCallback));
+
     // Launch createCallback
     mbgl::DefaultFileSource *defaultFileSource = reinterpret_cast<mbgl::DefaultFileSource *>(defaultFileSourcePtr);
-    defaultFileSource->createOfflineRegion(definition, metadata, [&env, &createCallback] (std::exception_ptr error, mbgl::optional<mbgl::OfflineRegion> region) {
+    defaultFileSource->createOfflineRegion(definition, metadata, [createCallback] (std::exception_ptr error, mbgl::optional<mbgl::OfflineRegion> region) {
 
         // Reattach, the callback comes from a different thread
-        jboolean renderDetach = attach_jni_thread(theJVM, &env, "Offline Thread");
+        JNIEnv *env2;
+        jboolean renderDetach = attach_jni_thread(theJVM, &env2, "Offline Thread");
         if (renderDetach) {
             mbgl::Log::Debug(mbgl::Event::JNI, "Attached.");
         }
 
         if (error) {
             std::string message = mbgl::util::toString(error);
-            env->CallVoidMethod(createCallback, createOnErrorMethodId, std_string_to_jstring(env, message));
+            env2->CallVoidMethod(createCallback, createOnErrorMethodId, std_string_to_jstring(env2, message));
         } else if (region) {
             mbgl::Log::Error(mbgl::Event::JNI, "Region created.");
-            jobject jRegion = env->NewObject(offlineRegionClass, offlineRegionConstructorId, region->getID());
-            // env->SetLongField(jRegion, offlineRegionIdId, region->getID());
+            jobject jRegion = env2->NewObject(offlineRegionClass, offlineRegionConstructorId, region->getID());
+            // env2->SetLongField(jRegion, offlineRegionIdId, region->getID());
 
-            if (env->ExceptionCheck()) {
+            if (env2->ExceptionCheck()) {
                 mbgl::Log::Error(mbgl::Event::JNI, "Exception.");
-                env->ExceptionDescribe();
+                env2->ExceptionDescribe();
             } else {
                 // This currently causes an exception on Android
                 mbgl::Log::Error(mbgl::Event::JNI, "Triggering Java callback.");
-                env->CallVoidMethod(createCallback, createOnCreateMethodId, jRegion);
+                env2->CallVoidMethod(createCallback, createOnCreateMethodId, jRegion);
             }
         }
 
         // Detach when we're done
-        detach_jni_thread(theJVM, &env, renderDetach);
+        detach_jni_thread(theJVM, &env2, renderDetach);
     });
 }