Скачать или смотреть How to Remove Map from List in Dart | Flutter

Learn how to effectively remove an item from a list of maps in Dart and Flutter. This guide provides step-by-step instructions and example code for your Flutter application.
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How to Remove Map from List in Dart | Flutter

When working with lists in Dart, particularly when handling collections of maps like JSON data, it's common to encounter situations where you need to remove certain items based on specific criteria. In this guide, we will address a common problem: removing an item from a list of maps. Specifically, we will focus on how to delete an item based on its vehicleNumber when a user presses a delete button in a Flutter application.

The Problem

You have a JSON list of vehicles where each item is represented as a map containing details such as vehicleNumber and vehicleType. Here is a sample of your list:

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

You want to delete a specific vehicle from _vehicleList based on the vehicleNumber when the delete button is pressed, but your initial code does not perform the operation as expected.

Your Current Approach

In your UI code, you set up a GestureDetector for handling delete actions:

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

However, using removeAt(_vehicleList[index]); is incorrect as removeAt expects an index, not the map itself.

The Solution

To effectively remove an item from the list, you can use the removeWhere method which allows you to specify a condition for removing elements from the list. Here's how you can do it:

Updated Code

Replace your delete button logic with the following:

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

Explanation of the Code

removeWhere Method: This method takes a test function that defines the criteria for removal. In this case, we check if the vehicleNumber matches the one you want to delete.

Anonymous Function: The expression (element) => element["vehicleNumber"] == 'KL-14-V-5208' is an anonymous function that returns true for any element matching the specified vehicle number, leading to its removal from the list.

Dynamic Deletion

If you want to dynamically delete the vehicle based on the vehicle number of the tapped item, you can modify your code snippet to use the vehicle number from that specific item like this:

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

Conclusion

With the removeWhere method, you can easily manage and manipulate lists of maps in Dart and Flutter. This approach allows for flexible item removal based on various criteria, providing a straightforward solution to the problem of deleting items from a list.

Now, you can implement this in your Flutter application and ensure users can delete vehicles as needed. Happy coding!