flutter-futurebuilder

问题 I have a comment page for each post in my app that I use streambuilder to fetch the comments from Firebase database. For each comment, I am displaying user's image and their comment. To get the user's image, I need to use a futurebuilder to find the user in the userData document and then grab the image url and display it (users can change their image profile, name, etc. at any time and I have to grab the updated one from the userData document every time I want to display their name or image

来源： https://stackoverflow.com/questions/64540805/why-futurebuilder-callback-is-not-calling-after-facebook-logged-in-data-in-flutt

来源： https://stackoverflow.com/questions/64540805/why-futurebuilder-callback-is-not-calling-after-facebook-logged-in-data-in-flutt

来源： https://stackoverflow.com/questions/64540805/why-futurebuilder-callback-is-not-calling-after-facebook-logged-in-data-in-flutt

来源： https://stackoverflow.com/questions/64540805/why-futurebuilder-callback-is-not-calling-after-facebook-logged-in-data-in-flutt

来源： https://stackoverflow.com/questions/63894705/futurebuilder-rangeerror-rangeerror-index-invalid-value-valid-value-range

来源： https://stackoverflow.com/questions/57224251/flutter-how-to-update-state-or-value-of-a-future-list-used-to-build-listvie

来源： https://stackoverflow.com/questions/57224251/flutter-how-to-update-state-or-value-of-a-future-list-used-to-build-listvie

来源： https://stackoverflow.com/questions/57224251/flutter-how-to-update-state-or-value-of-a-future-list-used-to-build-listvie

问题 I get the following error: A value of type 'Future<int>' can't be assigned to a variable of type 'int' It might be another type instead of int , but basically the pattern is A value of type 'Future<T>' can't be assigned to a variable of type 'T' So... What exactly is a Future ? How do I get the actual value I want to get? What widget do I use to display my value when all I have is a Future<T> ? 回答1: In case you are familiar with Task<T> or Promise<T> and the async / await pattern, then you