StatelessSurface<T> Composable

Handling Single State : Implementing Reusable Data-Driven Components with StatelessSurface

Understanding StatelessSurface and Its Use Case

Scenario:

Imagine you're building a news app where you want to display a list of articles from a remote server. In this case, the primary goal of the view is to fetch and display the articles, without requiring any user interaction or state changes within the view itself.

StatelessSurface and Its Role:

The StatelessSurface composable is ideal for this scenario because it's designed to handle a single state: the loading state. It doesn't require the view to maintain its own state for displaying the data.

How It Works:

1. Data Fetching: The view model fetches the list of articles from the server.

2. Data Binding: The StatelessSurface component is provided with the RemoteData object containing the fetched articles or an error message.

3. State Handling: The component automatically handles the loading state:

   • If data is not available (initial state or loading), it displays a loading indicator.

   • If an error occurs, it displays an error message.

   • If data is available, it displays the articles.

Example Usage

@Composable
fun NewsDetailScreen(newsId: Int) {
    val newsItem = viewModel.getNewsById(newsId).collectAsState()

    StatelessSurface<News>(
        remoteData = newsItem.value,
        loadingView = {
            CircularProgressIndicator()
        },
        errorView = { errMsg ->
            Text(text = "Error: $errMsg")
        },
        content = { news ->
            NewsDetails(news)
        }
    )
}

Key Points:

• Single State: StatelessSurface is primarily concerned with the loading state.

• Data-Driven: The view's appearance and behavior are driven solely by the data provided.

• Simplified Logic: The component handles common loading and error scenarios, reducing boilerplate code in the view.

Contrast with Stateful Views:

In contrast to stateful views, where the view maintains its own state (e.g., form input values, button states), StatelessSurface is designed for scenarios where the view's primary purpose is to display data without requiring user interaction or state changes.

In Summary:

StatelessSurface is a valuable tool for building simple, data-driven views that can efficiently handle loading and error states. It's particularly well-suited for scenarios where the view's primary goal is to display data from a remote source.