我应该如何从根本上提高 flutter 应用程序性能？

Question

Okay, so this might be a long read for your, but may solve many problems for newbies like me. Ok now straight to the point, How exactly should I improve performance, while loading a bunch of list data from firestore and preventing the application from crashing. Here is what happened with me, I'm developing a food delivery application and till now there are around 50 restaurants in this app, to what happened is, many of the low budget phones (specially vivo) didn't take the load and the app got crashed, so I limited the number of document to load at a time, but this actually affects the UX, there are competitors here which are way faster than our, I don't know what technology they've used but they're loading 98 restaurant in instant without any loading time and well I also tried to load data in the background, but the app crash with this to, So right now I'm stuck with limiting the number of document, but how can I improve? Currently the Homepage consists 10.network image cards, 3 asset image stack cards with gradient color and the list of 5 restaurants, which will be increased as the usee scrolls down but loading data isn't fast enough. Any one suggest me a way to speed it up or do I have to change the database?

Answer 1

So, I think your app is slow because when something changes in the app, it renders all the widgets again and again, and it slows the app. Some basic solutions are:

1- Use const on the variables that never changes. (For example: const Color colorPrimary = Color(0xffaabbcc));

2- Use Provider package to load and store your data, so that you can use your data everywhere. Also, it prevents all widgets to render. It only renders the widget which uses that data. (For example, you don't want to render AppBar if you don't change your AppBar title everytime)

3- Divide your large widgets into separate small widgets. It makes your project management easy.

4- Maybe your images are big, and your app can't load them fast, then it crashes. Make their size smaller. (For example: 256x256 instead 512x512)

5- Use lazy loading when loading your data. Maybe your app tries to load all the data once, and it makes your app slow. With lazy load, most of the data won't be loaded until user scrolls down. (I think you're already using it, but I just wanted to mention it)

These are possible solutions.

Answer 2

You can shrink your app if you're concerned about your application performance in release mode it uses different techniques to make your app more efficient by removing unused code from your app which is known as shrinking and many other techniques like Obfuscation which shorten the class names and methods, you can check this link for more information https://developer.android.com/studio/build/shrink-code .

Answer 3

Not sure if you still need an answer, but I believe your problem is related to loading all the views at once.

If your app crashes on startup only when you are loading too many results, most probably you are not using a ListView.builder to asynchronously load all the views.

My advice for you would be the following:

1. Lazy load your UI using ListView.builder . This will allocate memory only for the views visible on the screen.
2. Double check that you are loading the data only once. You haven't share any code, but I ran into this issue once, where my Future was being called every time the state of the widget would rebuild.
3. Use stateless widgets as much as possible. Split your widgets into reusable components and make as many const stateless widgets as possible.

If you want a detailed exampled you can check Tip number 4 in this article .

Answer 4

I did found a solution in 2020 itself, the reason for crash and slow speed were images, large images.