wrap applink signer code and return blank result when catch error

lib/provider/app_links_service.dart

@@ -88,6 +88,7 @@ class AppLinksService with PermissionCheckMixin {
     }, (app, signer) async {
       String? response;
 
+      try {
         if (type == "sign_event") {
           var tags = eventObj["tags"];
           Event? event = Event(
@@ -97,10 +98,9 @@ class AppLinksService with PermissionCheckMixin {
           event = await signer.signEvent(event);
           if (event == null) {
             log("sign event fail");
-          return;
-        }
-
+          } else {
             response = event.sig;
+          }
         } else if (type == "get_relays") {
           response = '{}';
         } else if (type == "get_public_key") {
@@ -114,22 +114,24 @@ class AppLinksService with PermissionCheckMixin {
         } else if (type == "nip44_decrypt") {
           response = await signer.nip44Decrypt(thirdPartyPubkey, authDetail);
         }
-
+      } catch (e) {
+        log("AppLinksService handleUri error: $e");
+      } finally {
         sendResponse(callbackUrl!, response);
+      }
     });
   }
 
   Future<void> sendResponse(String callbackUrl, String? response) async {
-    if (StringUtil.isBlank(response)) {
-      return;
-    }
-
-    if (callbackUrl == UNKNOWN_CODE) {
+    if (callbackUrl == UNKNOWN_CODE && StringUtil.isNotBlank(response)) {
       Clipboard.setData(ClipboardData(text: response!));
       return;
     }
 
-    var url = callbackUrl + Uri.encodeComponent(response!);
+    var url = callbackUrl;
+    if (StringUtil.isNotBlank(response)) {
+      url += Uri.encodeComponent(response!);
+    }
     var uri = Uri.parse(url);
     // if (await canLaunchUrl(uri)) {
     await launchUrl(uri);