Memory Leaks in Flutter

Rishabh Bisht

27 November 2024

Memory management is technically a crucial operation for the computer. Without proper management, you may encounter issues like application failure, or the system slow down vastly.

So, today we will learn about the Memory Leaks in Flutter and how to handle these leaks in our code.

What is a Memory Leak?

A memory leak in Flutter, or in any programming context, is the condition or stage where your program progressively uses memory without releasing or deallocating the previous unrequired memory.

This can lead to server issues like bad performances, unresponsive applications, or even crashes due to running out of memory.

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Reasons for Memory Leak in Flutter

Memory Leaks may occur for many reasons. Here are some of the most common reasons.

Unclosed Streams: Unclosed Streams is the condition when we create the stream but forget to close it. Streams can keep references to objects in memory even after they are no longer used causing memory leaks.

import 'dart:async';

void main() {
  StreamController&lt;String&gt;  _streamSubscription = StreamController&lt;String&gt;();

   _streamSubscription.add("Hello, World!");

   _streamSubscription.stream.listen((data) {
    print("Received data: $data");
  });

}

import 'dart:async';

void main() {

StreamController<String> _streamSubscription = StreamController<String>();

_streamSubscription.add("Hello, World!");

_streamSubscription.stream.listen((data) {

print("Received data: $data");

});

}

2. Global Variables: The garbage collector does not work when storing references to objects or widgets as global variables. So we need to deallocate that memory as it can also cause memory leaks.

3. Widget Trees: In Flutter, incorrectly placing the widgets on the widget tree, especially when using the stateful widget can also cause memory leaks in Flutter.

How to Detect Memory Leak in Flutter?

Detecting memory leaks in your Flutter application can be a bit challenging but it is possible. Here are several techniques and tools that can identify and fix memory leaks in Flutter Application.

Flutter DevTools: Flutter DevTools is a performance and debugging tool for Dart programs and Flutter applications. You can use Flutter DevTools to check your app’s memory usage.

You can access the Flutter DevTools by running the following command:

flutter pub global run devtools

1	flutter pub global run devtools

Heap Snapshots: You can also take heap snapshots to check the memory usage and leaks at a specific point in time.

Heap snapshots can help you identify objects that are not being garbage collected as expected.

Analyze Your Code: You must review your code and pay close attention to objects. Now check if the objects are properly disposed of when they are no longer needed.

You must also check for the controller as they are one of the most common causes for memory leaks in Flutter.

Preventing Memory Leaks in Flutter

To prevent memory leaks in Flutter applications or in dart programming, it’s important to manage the resources, dispose of the objects, and clean up after widgets or components when we do not require them.
Also as a developer, you must pay close attention to the lifecycle of flutter widgets and objects and use predefined methods like the dispose method for widgets, and StramSubscription cancellation for streams. You should also practice using weak references to help manage memory effectively.

@override
  void dispose() {
    // Cleanup and resource release code goes here
    object = null; //dereferencing the objects 
    _streamSubscription.cancel();  // for cancelling the stram subscription
    super.dispose(); // Always call the super.dispose() method
  }

@override

void dispose() {

// Cleanup and resource release code goes here

object = null; //dereferencing the objects

_streamSubscription.cancel(); // for cancelling the stram subscription

super.dispose(); // Always call the super.dispose() method

}

Conclusion

So, In this article, we have learned various things about memory leaks, their cause and prevention techniques in flutter.

Learn more about the Prevention of Memory Leaks in Flutter. You can also check out more amazing blogs on Flutter with Mobikul Blogs.