There are many questions related to how we can improve the performance of our Flutter app. Usually, Flutter apps are productive by default, so you only need to avoid making some mistakes when writing the code to make the application run in an excellent and fast way. With the tips that we will consider in this article, we could avoid frequent errors, that are made during the optimization of Flutter applications.
Large Build Function
One of those mistakes is a very large build function. Instead of having one big widget, you better have to split it into many small widgets. Let’s also not forget to use const as much as possible for our widgets, this allows us to catch and reuse widgets to avoid unnecessary rebuilds that are caused by their ancestors.
Secondly, you should avoid of repetitive and costly work in build() method. Since build method can be called frequently when ancestor Widgets are rebuild, a costly build method will consume more CPU power than needed.
Thirdly, use the Opacity Widget only when necessary, especially during the animation. As we see the animation works, however, animating Opacity widget directly causes the widget to rebuild each frame, which is not very efficient. Instead of it, try to use its alternatives: AnimatedOpacity, TransparentImage, FadeInTransition.
The fourth mistake is the use of “Expensive Widgets”. Clipping Widgets, ShaderMask, ColorFilter, Chip and Text may prove expensive. Use effects carefully, as they can be expensive too. Some of them invoke saveLayer() behind the scenes, which can be a costly operation.
The next is “Lazy Widgets”. Try to use Lazy Lists and Lazy Grids whenever needed. This will only create those elements that are currently seen on the screen.
Everybody knows that Flutter is powerful enough to run our apps without mistakes, but it is always good to follow good practices and optimize our app as much as possible. Because during the rebuild, if the widget does not change, then Flutter internally does the optimization for you. The widget will be treated as constant and will not be rebuild.