Stop Custom Function Frustration: Unlock FlutterFlow's True Potential

Are you hitting a wall with custom functions in FlutterFlow, seeing error messages like "The function is empty or cannot be parsed"? It's a common problem, but thankfully, the solution is straightforward. This guide will show you how to work with FlutterFlow's constraints to build powerful features for your app, focusing on creating effective solutions, and understanding the limits of FlutterFlow custom functions.

The FlutterFlow Custom Function Trap: Why Your Code Isn't Saving

FlutterFlow's custom functions offer a way to extend your app's capabilities, but they come with limitations. The key is understanding where and how to write your code.

• Limited Scope: Custom functions in FlutterFlow are designed for simple, synchronous operations.
• No External Imports: You can't import new libraries like http or dart:convert within a custom function.
• Asynchronous Operations Prohibited: Custom functions cannot be async or return a Future.

Ignoring these rules leads to the "cannot be parsed" error and your function not saving. So, how do you perform complex tasks like making API calls to fetch latitude and longitude from an address without breaking the rules?

Unleash FlutterFlow's Power: Embrace Custom Actions

The answer is custom actions. Think of custom actions as the powerhouse of your FlutterFlow app, designed for tasks that go beyond simple calculations.

• Asynchronous Operations are Welcome: Custom actions are designed to be asynchronous.
• Full Import Freedom: Import any Dart package you need, including http, dart:convert, and more.
• Seamless Integration: Custom actions integrate seamlessly with your FlutterFlow UI and logic.

To implement the getLatLngFronAddress function, migrate your code from a custom function to a custom action. Here's how:

1. Create a Custom Action: In FlutterFlow, navigate to the "Custom Code" section in the left sidebar and create a new custom action.
2. Copy and Paste (with Minor Tweaks): Move your existing code into the custom action editor, remember to add the necessary imports

   import 'dart:convert';
   import 'package:http/http.dart' as http;
   
   Future<List<double>?> getLatLngFromAddress(String address) async {
     final apiKey = 'YOUR_API_KEY'; // Secure this with a secret parameter
     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 {
         print('Geocoding failed: ${data['status']}'); // Use print for debugging
         return null; // Important to return null in case of failure
       }
     } else {
       print('HTTP error: ${response.statusCode}'); // Use print for debugging
       return null; // Handle HTTP errors gracefully
     }
   }
   

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3. Configure Parameters: Define the function parameters as needed (e.g., the 'address' string).
4. Set Return Value: Specify the return type (e.g., List<double>?).
5. Use it in your project: Now you can use the custom action in your project, for example to update the lat and lng of a location in your database.

Maximizing Value: Securing Your API Key

Never hardcode your API keys directly in your code. Exposing them can lead to security vulnerabilities and unexpected costs. Leverage FlutterFlow's 'Secret Parameters' to securely store your API key and access it within your custom action.

Key Takeaways

• Custom actions are for complex operations involving API calls, asynchronous tasks, and code imports.
• Custom functions are for simple, synchronous calculations that can be performed without external libraries.

By understanding the difference and using each tool appropriately, you'll unlock the full potential of FlutterFlow and build robust, feature-rich applications.