yulkin

yulkin

Programming Flutter: Image.toByteData() does not exist (page40)

your book suggests to use Image.toByteData() to convert image to bytes, however I get the following error: "the getter ‘toByteData’ isn’t defined for the type ‘Image’. "

I tried importing the dart:typed_data package, but seems that this method does not exist. Can you please explain how to access it? It would be very useful for my app.

Most Liked

carminezacc

carminezacc

Author of Programming Flutter

I’m terribly sorry for being so late to answer, but I wasn’t 100% aware of how DevTalk worked and I wasn’t getting notified of new posts, but now it should never happen again.

Anyway, you’re confusing the dart:ui’s Image class with the Image widget, on page 253 there is a little section about using ui.Image with a link to the page of the official reference about it, which tells you how to get an ui.Image object, in that code you’re just getting an Image widget and trying to cast it to an ui.Image object, when instead you should follow the instructions in the book (and in the official reference).

What you’re actually trying to do seems to me to have nothing to do with the Image object, as you can get the bytes for the image by running readAsBytes on the io.File directly.

Hope this answers your question, feel free to reply back and, again, I’m really sorry for being very late.

Where Next?

Popular Pragmatic Bookshelf topics Top

jimschubert
In Chapter 3, the source for index introduces Config on page 31, followed by more code including tests; Config isn’t introduced until pag...
New
jeffmcompsci
Title: Design and Build Great Web APIs - typo “https://company-atk.herokuapp.com/2258ie4t68jv” (page 19, third bullet in URL list) Typo:...
New
sdmoralesma
Title: Web Development with Clojure, Third Edition - migrations/create not working: p159 When I execute the command: user=> (create-...
New
lirux
Hi Jamis, I think there’s an issue with a test on chapter 6. I own the ebook, version P1.0 Feb. 2019. This test doesn’t pass for me: ...
New
Chrichton
Dear Sophie. I tried to do the “Authorization” exercise and have two questions: When trying to plug in an email-service, I found the ...
New
swlaschin
The book has the same “Problem space/Solution space” diagram on page 18 as is on page 17. The correct Problem/Solution space diagrams ar...
New
taguniversalmachine
Hi, I am getting an error I cannot figure out on my test. I have what I think is the exact code from the book, other than I changed “us...
New
Henrai
Hi, I’m working on the Chapter 8 of the book. After I add add the point_offset, I’m still able to see acne: In the image above, I re...
New
bjnord
Hello @herbert ! Trying to get the very first “Hello, Bracket Terminal!" example to run (p. 53). I develop on an Amazon EC2 instance runn...
New
dachristenson
I just bought this book to learn about Android development, and I’m already running into a major issue in Ch. 1, p. 20: “Update activity...
New

Other popular topics Top

AstonJ
SpaceVim seems to be gaining in features and popularity and I just wondered how it compares with SpaceMacs in 2020 - anyone have any thou...
New
DevotionGeo
I know that -t flag is used along with -i flag for getting an interactive shell. But I cannot digest what the man page for docker run com...
New
Exadra37
On modern versions of macOS, you simply can’t power on your computer, launch a text editor or eBook reader, and write or read, without a ...
New
AstonJ
I have seen the keycaps I want - they are due for a group-buy this week but won’t be delivered until October next year!!! :rofl: The Ser...
New
dimitarvp
Small essay with thoughts on macOS vs. Linux: I know @Exadra37 is just waiting around the corner to scream at me “I TOLD YOU SO!!!” but I...
New
PragmaticBookshelf
Learn different ways of writing concurrent code in Elixir and increase your application's performance, without sacrificing scalability or...
New
mafinar
Crystal recently reached version 1. I had been following it for awhile but never got to really learn it. Most languages I picked up out o...
New
AstonJ
Continuing the discussion from Thinking about learning Crystal, let’s discuss - I was wondering which languages don’t GC - maybe we can c...
New
mafinar
This is going to be a long an frequently posted thread. While talking to a friend of mine who has taken data structure and algorithm cou...
New
PragmaticBookshelf
Author Spotlight: Karl Stolley @karlstolley Logic! Rhetoric! Prag! Wow, what a combination. In this spotlight, we sit down with Karl ...
New

Sub Categories: