This project is a sample Flutter/Dart app demonstrating how to find the
user's location from the device, look up weather information from the
NWS, and display a table and a graph of the data. Currently, it only
deals in barometric pressure, so the app is called pressure. This
might change later.
The scope of this sample is very limited since it was mostly an exercise in teaching myself Flutter/Dart over a weekend, but perhaps it will be useful for someone who finds it! As implied in that statement, I am not an expert by any means. But hopefully, if you're reading this, you can find something useful in the example code to help your own project.
- I have not tested this with iOS (only Android Pie on a Pixel 1)
- I have not tested this outside of the US (or really anywhere besides my home in Seattle)
This project is licensed under the MIT license.
You'll need to have a working Flutter setup, preferably on Android Studio. More information about that setup can be found here:
After opening the project in Android Studio, you may need to open the
pubspec.yaml and click Packages get. You should then be able to
start the app in a connected Android device.
The code is organized into four main lib modules, and one test module.
The app entry point and the top level app widget live here. This also creates location and weather lookup objects for a real device.
Implements a stateful widget that contains most of the app's user interface.
A top level build() method takes care of putting together all of the
pieces, which are chosen based on the app's current state. Before
information is available, the user is shown a spinner with some text
describing what the app is waiting for. (Note that the app does not
auto-request the information, but waits for the user to tap the refresh
button. This is done to make it simpler to control the execution for
debugging and inspection, since this is a sample app and not a production
app.)
When the user taps the refresh button, _requestUpdate() is called,
which kicks off an async update process using the location and weather
data collector objects that were passed down from the app container.
The final widget build pulls together a larger title Text with the
name of the user's city and postal code, a table of observations from
the NWS API, and a graph showing the past few hours of values.
The LocationInfo class is defined here to contain information about
the user's location. As the raw Dart location API returns a simple
map from string to value, the RealLocation class converts that "soft"
data structure into something more strongly typed for the rest of the
app to use. FakeLocation is also available for unit testing, and to
let you plug in synthetic locations for app testing.
The actual query logic is written asynchronously, using the async
keyword.
The Observation class contains strongly typed information about a
single weather observation; the weather data objects will return
several. (Currently, it is hard-coded to four hours of data, but this
could be changed to be more flexible.) Observation also provides a
formatting function for the tabular display in the UI.
RealWeather implements an actual RESTful client which talks to the NWS
REST services. (As of this writing, it does not require an explicit
API key, but they do request mentioning the client name and contact
info in the User-Agent header; if you fork this project, please change
the headers to have your contact information.) FakeWeather implements
a mock for unit testing, and to let you plug in synthetic data for app
testing.
The actual query logic is written asynchronously, using the async
keyword.
Contains a minimally updated version of the default Flutter test suite, adapted for the Weather Pressure app. A test app container widget is created, which passes in fake location and weather query objects. A user tap on the refresh button is simulated, and the results are checked.