Merge pull request #469 from easemob/flutter2_dev

Flutter2 dev

Author: dujiepeng

android/src/main/java/com/easemob/im_flutter_sdk/EMHelper.java

@@ -526,7 +526,44 @@ static Map<String, Object> toJson(EMMessage message) {
         }
 
         if (message.ext().size() > 0 && null != message.ext()) {
-            data.put("attributes", message.ext());
+            HashMap<String, Object> map = new HashMap<>();
+            for (Map.Entry entry:message.ext().entrySet()) {
+                String key = entry.getKey().toString();
+                try {
+                    JSONObject value = message.getJSONObjectAttribute(key);
+                    map.put(key, value);
+                    continue;
+                }
+                catch (HyphenateException e) {
+                }
+                try {
+                    boolean value =  message.getBooleanAttribute(key);
+                    map.put(key, value);
+                    continue;
+                } catch (HyphenateException e) {
+                }
+
+                try {
+                    JSONArray value = message.getJSONArrayAttribute(key);
+                    map.put(key, value);
+                    continue;
+                } catch (HyphenateException e) {
+                }
+                try {
+                    int value = message.getIntAttribute(key);
+                    map.put(key, value);
+                    continue;
+                } catch (HyphenateException e){
+                }
+
+                try {
+                    String value = message.getStringAttribute(key);
+                    map.put(key, value);
+                    continue;
+                } catch (HyphenateException e) {
+                }
+            }
+            data.put("attributes", map);
         }
         data.put("from", message.getFrom());
         data.put("to", message.getTo());