Скачать или смотреть How to Fill a List in Flutter from Another Page

Learn how to easily fetch data from one Dart page and populate a dropdown list in Flutter using clean, efficient coding techniques.
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How to Fill a List in Flutter from Another Page

When developing applications in Flutter, you may often encounter scenarios where you need to fetch data from one page and use it in another. One common challenge is populating a dropdown list with data fetched from an external source. In this guide, we will explore how to achieve this using the fetchDept function to fill a list on a different Dart page effectively.

Understanding the Problem

You have a method fetchDept() designed to retrieve a list of departments from a remote server. This data needs to be loaded into a dropdown list on a separate page — in this case, the DropListPage. The goal is to ensure that once the data is fetched, it can be displayed in the dropdown menu. Let's break down the solution into manageable steps.

Step-by-Step Solution

1. Define Your Data Fetch Function

In the fetchDept.dart file, you already have the fetch function defined:

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This function retrieves data from a specified URL. It's important to handle both the data retrieval and any potential errors that may occur.

2. Setting Up the DropListPage State Class

In your Details.dart file, you need to modify the DropListPage to hold a list that will store the fetched data from fetchDept(). Here’s what the updated code looks like:

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In this code:

State Management: We create a deptList to hold the fetched departments.

initState: This is where we call asyncMethod() to initiate the fetching process as soon as the page loads.

asyncMethod: This method handles fetching the data and updates the state with the results using setState().

3. Building the Dropdown Widget

Now that we have the data populated in the deptList, we can use it to construct our dropdown list. You would typically incorporate a widget like below to display your dropdown:

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This dropdown will populate with items based on the data available in deptList and will allow the user to make a selection.

Conclusion

By following these steps, you can easily fetch data from one Dart page and use it to populate a dropdown list in another page within your Flutter application. Leveraging asynchronous methods and updating the UI with setState() ensures your application remains responsive and user-friendly.

With this structured approach, you can handle similar data fetching tasks in your Flutter projects efficiently. Happy coding!