jacobqvist/demo-flutter

Flutter application that communicates with ESP32 devices through toit.io.

Demo of controlling IoT devices with Flutter

A project showcasing how a Flutter app can talk to an embedded device using Toit.

This project is intended to be used as starting point for Flutter applications that want to communicate with embedded devices or the Toit server. Just pick the functionality that is most similar to what you need, and remove the remaining pages.

Implementation Note

The Flutter app needs access to the Internet. The android/app/src/main/AndroidManifest.xml thus must include:

<uses-permission android:name="android.permission.INTERNET"/>

We have used Riverpod as state-management framework. It would be straight-forward to switch to a different framework, like Bloc.

Run the Demo

flutter run

For running the tests:

flutter test

Managing Devices

The "List Devices" page demonstrates how the Flutter app can connect to the Toit server to query all available devices.

It serves as a starting point for applications that want to manage the Toit fleet, or simply want to show the status of existing devices.

Device Logs

The "Log" example connects to the Toit server to receive the logs of a selected device. It is one of the simplest API calls and serves as a good starting example.

However, the logs often contain valuable information, so this example is frequently useful in real apps.

Run

This page shows how to run code on the device. This functionality is used in multiple demos, which is why a separate run-widget has been created.

The used 'run' command has many limitations. It doesn't support multiple files, and the program can only run for a limited time. Different API endpoints are responsible for managing the installed applications.

Pubsub Send

A simple pubsub example that sends a notification to the device.

This functionality can be used to send commands to devices. The Toit server will make sure that all notifications are eventually sent to the corresponding device (only giving up after 7 days).

Since this demo requires a receiving application on the device side, it also has functionality to temporarily run a Toit program on the device (similar to the "Run" demo). This functionality is independent and would normally be removed from the Flutter application.

Pubsub Listen In

This page demonstrates how a Flutter application can listen to events that are sent to a specific topic.

The application creates a fresh subscription, which means that it will only receive data that is sent once the subscription was created. Having its own subscription also means that it won't interfere with other listeners to the same topic.

This demo is primarily useful for devices that regularly send sensor data (like temperature, or distance) to the Toit servers, but where the Flutter application doesn't need stale data.

Pubsub Listen Heartbeat

This example illustrates how a Flutter app can request a device to start producing data, so it can listen to it.

If producing data is expensive (in terms of power, bandwidth, ...), then devices should only generate data if there is a listener for it. The listeners thus initiate the generation of data by sending a request. The listeners are furthermore supposed to send a 'stop' signal, when they don't need data anymore. However, listeners may misbehave (for example by losing power). To protect against missing 'stop' events, the device requires listeners to send heartbeat notifications at fixed intervals to ensure that they are still alive and are still interested in the data.

Note: in this example, the request to receive data, and the heartbeat notification have been merged.

Pubsub RPC

In this demo, the pubsub API is used to establish an RPC (remote procedure call) channel, so that the Flutter app can invoke methods on the device.

It uses the 'publish' functionality to send requests to the device, and receives the response in a stream.

The demo only supports methods that are initiated by the Flutter app, but it would be trivial to extend it so that the device can invoke end-points on the Flutter side as well.