FlutterFlow Custom Function Frustrations? Here's How to Fix the "Empty or Cannot Be Parsed" Error

Having trouble saving your custom function in FlutterFlow, getting that cryptic "empty or cannot be parsed" error? It's a common problem, especially when trying to use async functions or custom imports like the http package. Let's break down why this happens and how to solve it.

The Problem: FlutterFlow Custom Function Limitations

FlutterFlow's Custom Functions have specific limitations:

• No Async Operations: They're designed for synchronous operations only. This means you can't use async or Future within them.
• Limited Imports: You're restricted to the FlutterFlow's automatically imported libraries. You can't add custom imports like http.

The FlutterFlow editor emphasizes this with the /// MODIFY CODE ONLY BELOW THIS LINE markers! It's easy to miss, but crucial to understand. The error is often triggered when this is not followed.

The Solution: Embrace Custom Actions

If you need to perform asynchronous tasks (like making API calls), or import custom libraries, Custom Actions are your answer. Custom Actions grant you the flexibility that custom functions lack. They fully support the use of async operations and custom imports. Making them better suited for complex operations within your FlutterFlow app.

Converting Your Function to a Custom Action: a Step-by-Step Guide

Here’s how to get your FlutterFlow code working:

1. Create a New Custom Action:

• In FlutterFlow, navigate to the "Custom Code" section, and select "Actions."
• Click "+ Create Custom Action."

2. Copy and Paste Your Code (with Modifications):

• Take code from your custom function:

import 'dart:convert';
import 'dart:math' as math;
import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.com';
import 'package:intl/intl.dart';
import 'package:timeago/timeago.dart' as timeago;
import '/flutter_flow/custom_functions.dart';
import '/flutter_flow/lat_lng.dart';
import '/flutter_flow/place.dart';
import '/flutter_flow/uploaded_file.dart';
import '/backend/schema/structs/index.dart';
import 'package:http/http.dart' as http;
Future<List<double>?> getLatLngFronAddress(String address) async{
/// MODIFY CODE ONLY BELOW THIS LINE
final apiKey =
'YOUR_API_KEY'; // Inserisci qui la tua API Key oppure usa a secret param
final url = Uri.parse(
'https://maps.googleapis.com/maps/api/geocode/json?address=${Uri.encodeComponent(address)}&key=$apiKey');
final response = await http.get(url);
if (response.statusCode == 200) {
final data = json.decode(response.body);
if (data['status'] == 'OK') {
final location = data['results'][0]['geometry']['location'];
final lat = location['lat'];
final lng = location['lng'];
return [lat, lng];
} else {
//debugPrint('Geocoding failed: ${data['status']}');
}
} else {
//debugPrint('HTTP error: ${response.statusCode}');
}
return null;
/// MODIFY CODE ONLY ABOVE THIS LINE
}

• Paste it into the Custom Action editor.
• Important: Keep the import 'package:http/http.dart' as http; statement.
• Remember to replace 'YOUR_API_KEY' with your actual Google Maps API key or use a secret parameter in FlutterFlow for safer handling. * It's best practice from a security perspective to not commit your API key to the code.

3. Configure Parameters:

• Define Inputs: Create an input parameter named address (String type) to accept the address you want to geocode.
• Define Return Value: Set the return value to "List of Double (Nullable)". This indicates that the action returns a list containing the latitude and longitude, or null if the geocoding fails.

4. Implement Error Handling:

• Wrap your http request in a try-catch block to gracefully handle exceptions.
• Return null if the API key is missing too.

5. Utilizing the Custom Action:

• Now, use this custom action in your FlutterFlow workflows.
• Pass the address to geocode as an argument, and handle a list of double values (Lat, Lng) that it will return.

Real-World Example: Geocoding Addresses for a Map

Let's say you have a form where users enter their address. You want to display their location on a map. The getLatLngFromAddress custom action helps you convert the address into latitude and longitude coordinates. Use conditional logic to display a message when geocoding fails. This improves user experience. It makes a great feature in any real estate app.

Boost Engagement with Location-based Features and Smooth Error Handling

Custom Actions empower your FlutterFlow app to perform complex tasks. By using http requests and implementing solid error handling, your FlutterFlow apps become more robust. With clear presentation of locations on a map, you will ensure higher user engagement. Don't get stuck with basic custom functions. Embrace the power of custom actions!