Flutter is an open-source, cross-platform app development framework, and the full credit goes to Google. Thanks to Flutter, developers can tailor the appearance and functionality of their apps. Developers do not have to write code for each platform, as one code will work smoothly everywhere.
Developing Flutter apps is easy, but maintaining them is hard, especially when they have several features and a massive user base. This is when optimizing such apps becomes necessary. Flutter apps may run into size, efficiency, and performance issues if developers don’t handle them properly.
Over a million Flutter-based apps run on the Play and App Store. This indicates the popularity of Flutter among companies and the developer community. In this blog, we will discuss ways to optimize app performance and more. Let’s get started.
5 Reasons to Optimize Flutter App Performance
Although Flutter has multiple benefits, it has certain built-in features that cause problems for apps. The blame does not lie with Flutter entirely. Even developers must be aware of Flutter’s limitations and code accordingly. We won’t get into the details, but below are a few reasons why Flutter app development companies must optimize apps to deliver better performance.
Performance and Smooth UI
Flutter uses a single thread to create UI elements. Burdening the thread with too many tasks can cause a dip in performance. When using Flutter, the screen must refresh in 16 milliseconds for smooth transactions. Too much work for a thread can result in lagging videos, especially for animations, page transitions, or scrolling.
Memory and Resource Usage
Flutter apps have everything inside to ensure they stay operational. The bundle includes the Dart programming language and the Skia graphics engine, along with images, sounds, and other necessary files. If developers don’t use Flutter properly, the consequences could be disastrous. For example, uncompressed media files can consume more memory, and poor widget rebuilds can hamper efficiency.
App Size (APK, IPA/Bundle)
Unlike other apps, a Flutter app contains its own engine that powers the code and UI. This results in large app files. Flutter app developers must optimize these apps to eliminate unnecessary code and unused resources. Unoptimized apps take up a lot of space. Popular techniques to optimize the app include tree-shaking, removing unnecessary assets, and splitting the app to reduce size.
Battery and Device Efficiency
An unoptimized Flutter app strains the user's device and reduces efficiency. If the app works on many tasks simultaneously, it can make animations look blurry and unattractive. Unnecessary rebuilds can also compel the device to use more power, ruining the overall user experience.
Scalability and Maintainability
A well-structured and optimized app becomes easier to comprehend, test, and modify. Adding a new feature or bug fixing becomes easy, thanks to optimization. In contrast, a poorly optimized app can result in more errors and degrade performance. Such problems add up over time and make the app harder to maintain and fine-tune.
10 Ways to Optimize the Performance of Flutter Apps
In the above section, we discussed why Flutter apps require optimization. Let’s explore the 10 ways to optimize the performance of Flutter apps.
1) Stateless Widgets
A stateless widget remains fixed and does not store data or track actions. Due to this attribute, a stateless widget uses less memory while being easy to handle. On the other hand, a stateful widget can change itself, depending on the data it receives and how users interact with it.
Stateless widgets eliminate the need for rebuilds in case of changes. It only updates certain parts that require updates. This ensures faster and improved performance.
2) Right Use of Images and Animations
Poorly optimized images and animations can ruin the user experience. Using images of the right size, compressing them, and loading them only when required are good practices. As far as animations are concerned, they should be smooth and simple. The trick is not to overdo it.
3) Use Keys for Performance Optimization
When working with dynamic widgets, Flutter app development companies must figure out which widget needs rebuilding. In the absence of keys, Flutter apps may malfunction and build more widgets than necessary. This results in poorly executed animations and sluggish performance. Keys guide widgets, which parts to rebuild, and not mess with parts that don’t require any changes.
4) Async and Await In Place of Then ( )
Time-consuming and complex tasks can slow down app performance. Developers can handle this problem in two ways.
- .then ( ) - With this method, developers can instruct the app to run code after the completion of a particular action. However, this may not work in the case of complex steps because it may compromise the code.
- Async and Await - These help developers write code like a set of instructions. Even though the app runs in the background, the steps unfold gradually. This results in clean, easy-to-read code.
5) Use Opacity and Clipping Sparingly
Using too many transparent images or visuals can burden the app. This requires the app to put in more effort, and the same goes for trimming objects to desired shapes and sizes. If transparency is the project’s need, it is advisable to give it some structure or shape. This will make it easier for Flutter to render it.
6) Minimize Deeply Nested Widget Hierarchies
Putting one widget inside another and repeating this process requires additional development and updates. Besides additional development work, complex widget hierarchies can slow down app performance. The best practice is to keep the widget tree simple. Alternatively, tools like ListView (for lists) and GridView (for grids) can solve this problem. They can help developers handle items easily without affecting performance.
7) Flutter DevTools for Performance Monitoring
Flutter DevTools is like a magic wand for Flutter developers. It's a toolbox that allows developers to get an X-ray view of the app while it's running. It helps with the following actions.
- Rendering - How the app understands widgets and transforms them into designs. Viewing the progress in real-time ensures developers can spot issues quickly.
- Memory Usage - Highlights how much memory the app uses. This tells developers if any files/widgets are hogging space unnecessarily.
- Widget Tree - Provides a 360-degree view of the widget structure to identify unnecessary parts.
Thanks to the toolbox, developers can quickly identify issues and solve them before they hamper performance.
8) Don’t Block the Main Thread
A Flutter app must work at 60 frames per second for a smooth animation. This means each frame gets 16 milliseconds. If it takes longer than 16 milliseconds, the animation would not meet the required standards. Below are a few tips to ensure smooth animations.
- Don't Block the Main Thread
The main thread should not do the heavy lifting, such as downloading huge files or performing complex calculations. Such actions will only cause the app to hang and slow down.
- Heavy Work in the Background
Use Future to run multiple tasks at the same time without burdening the system. Isolate is preferable to run complex and system-intensive tasks.
- Keeping the UI Thread Free
The main thread should be reserved for drawing the screen and responding to user actions like touches and animations. On the other hand, the background thread should focus on handling heavy tasks such as image processing, downloads, and number computations.
9) Flutter DevOps to Monitor Performance
Use Flutter DevOps to track the time required to build each frame. This highlights parts slowing down app performance.
10) Release Mode for Testing Speed
To see the actual app performance, test the app in release mode. Debug mode may not be appropriate as it's generally slower.
Summing Up
Undoubtedly, Flutter is a powerful framework for creating innovative, high-performance apps that match the needs of businesses. That said, like every app, even Flutter apps need optimization over time to ensure they keep delivering optimal performance. These tricks and techniques can help companies and Flutter developers optimize app performance. Doing so will ensure customer satisfaction and improve market reputation.
If you lack the required expertise, tools, or in-house talent for the same, consider partnering with a leading Flutter app development company.
