FutureBuilder Explained | Flutter for Android Developers

What’s FutureBuilder?

The FutureBuilder class is a widget that builds itself based on the latest snapshot of interaction with a Future. It is essential for handling asynchronous data in Flutter applications. Key properties include ‘future’, which holds the asynchronous computation, and ‘builder’, which is a callback that defines how to build the widget based on the snapshot.

Check the official documentation for more.

FutureBuilder explained for Android Developers

For Android developers, the FutureBuilder can be compared to using LiveData or RxJava in Android. Just like LiveData observes data changes and updates the UI accordingly, FutureBuilder listens to the completion of a Future and rebuilds the widget when the data is available. This is similar to how Kotlin coroutines work with suspend functions to handle asynchronous tasks.

Example Code

Here is an example of how to use FutureBuilder:

FutureBuilder<String>(
  future: fetchData(), // a function that returns a Future
  builder: (BuildContext context, AsyncSnapshot<String> snapshot) {
    if (snapshot.connectionState == ConnectionState.waiting) {
      return CircularProgressIndicator();
    } else if (snapshot.hasError) {
      return Text('Error: ${snapshot.error}');
    } else {
      return Text('Data: ${snapshot.data}');
    }
  },
);

FutureBuilder Remarks

In conclusion, the FutureBuilder class is a powerful tool for Flutter developers to handle asynchronous data. By understanding its properties and how it compares to familiar Android concepts, developers can effectively manage data loading states in their applications.