Скачать или смотреть How to Display Contact Names in a List View Widget in Flutter Using Bloc

Learn how to successfully fetch and display contact names in a ListView widget in Flutter using Bloc, complete with sample code and troubleshooting tips.
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This video is based on the question https://stackoverflow.com/q/72114160/ asked by the user 'nidhi patnaik' ( https://stackoverflow.com/u/19033905/ ) and on the answer https://stackoverflow.com/a/72114370/ provided by the user 'jnk.sch' ( https://stackoverflow.com/u/16640330/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Troubleshooting Flutter: Displaying Contact Names from Phone in a List View

Flutter allows developers to create beautiful and responsive applications, but sometimes fetching and displaying data can pose a challenge. A common issue arises when trying to display contact names from a phone in a list view widget using Bloc. This post will walk you through a concise yet effective solution.

The Problem

You might be trying to fetch contacts using the Bloc pattern within Flutter, but facing an issue where no contact names are being displayed on your interface. This is particularly frustrating as you're relying on printed statements to debug and ensure data is fetched correctly, yet those statements return empty.

Understanding the Solution

Step 1: Modify the DataService Class

First, ensure that your getPhoneContacts method in the DataService class returns the list of contacts. Currently, the implementation only prints the names to the console without passing them back to where they are needed.

Change the method’s return type to Future<List<Contact>>.

At the end of this method, return the list of contacts.

Here’s the corrected code snippet:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Update the ContactCubit

Now that the DataService is correctly returning contacts, you need to update your ContactCubit class to use this returned data. You’ll assign the results of your contact fetch to a variable and emit this data as the state.

Replace your getContacts method with the following:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Implementing BlocBuilder

In your widget, you will use BlocBuilder to access the contacts and display them in the ListView. Make sure to reference the updated state:

Replace your BlocBuilder implementation with the following:

[[See Video to Reveal this Text or Code Snippet]]

Recap

By modifying the DataService to return the list of contacts and adjusting the ContactCubit to emit this data, you can successfully retrieve and display contact names in your Flutter application.

If you follow these steps, you should see the intended contact names appearing in your overlay widget’s ListView, making your app much more functional and user-friendly.

Conclusion

The Bloc pattern in Flutter is powerful for managing state, but it requires careful attention to how data flows through your application. By ensuring that your methods are returning data as expected and that your Bloc is managing state properly, you can overcome common challenges like displaying contacts.

Now that your code is updated, restart your app and check to see if you can view your contacts as intended. Happy coding!