I am currently using a TabBarView to display a long list of images (think picture gallery or manga reader).
It seems that each image is only loaded when I start swiping to the new page, i. e. when the edge of the new page becomes visible.
In an Android ViewPager we had setOffscreenPageLimit to be able to pre-create pages that are still off screen.
Is there a similar functionality in TabBarView or would I have to implement the preloading at a lower level, e. g. prefetching the images and caching them locally?
Bonus question: Is TabBarView even the correct widget for this use case or is there a more light weight alternative (considering I do not want simple scrolling but swiping and self-centering pages).
I don't think we currently have built-in support for preloading tabs in TabBarView. You could add it yourself, or using createLocalImageConfiguration and NetworkImage.resolve, you could cause images to be cached.
Related
I'm building a web app with Flutter, and I was wondering what the best options are for displaying a modal data entry form that does not need to take the whole screen space.
Initially, I was looking at pushing another Scaffold based screen, but that takes up the whole screen space.
Any suggestions?
My humble solution is to wrap your Scaffold's body's Widgets in a Stack.
You can choose whether or not to display the form using if (someState) ... inside the children list.
The form itself can be wrapped in a Card that is wrapped in a Center Widget.
There might be better solutions but that's what I use.
I designed three onboarding pages in figma which contains information about my app, while wireframing the app, I added smart animate to the three pagesThis is the first onboarding page
The second one
The third one
The smart animate enables smooth transition from each page to each page
While using flutter, I created 3 different pages for each onboarding pages and added a navigation widget to each button
But the navigation from each page to each page was stacked
I also tried using gesturedetection() onhorizontalswipe still same result
The pages navigate in a stacked way totally different from figma's smart animate option.
Is there anyway I can do this?
I'll appreciate any help
Thanks in advance.
From what I understood,
You want to build an onboarding screen with some animation. But the pages are being stacked.
It is happening because you are navigating to different pages with each button press. That is very bad practice for building an onboarding screen.
You should be using a PageView widget that allows you to transit between pages without navigating to them.
If you want to use a plugin that suits you, I would recommend introduction_screen
my job is to create a few widgets using widgetkit and swiftui, however the main project is build on uikit so I am not very good with swiftUI. Nevertheless, I would like to know whether I can add a graph inside of, for example, medium sized widget, and can the graph be scrollable to reveal more information? Or could it only be clickable? Thank you.
I know how widgets work, just interested in whether it is possible to create a scrollable graph inside of a medium sized widget.
I'm only just getting started with widgets myself, so happy to be corrected. But interactivity with widgets is very limited - effectively to taps and nothing else. They're designed more to be informational displays than interactive user interfaces.
If your widget is larger than the small size (the square one that takes up the same space as 2x2 app icons on the iPhone home screen), you can have multiple tap targets. For example, if your widget had a list of calendar items, you could set it up so that a user tapping on a specific item opened the app with a view showing that item in more detail.
So no, a scrollable graph isn't feasible. But what you can do is create a graph that shows a snapshot of data that a user is most likely to find useful when glancing at their home screen – and making sure that if they tap on it, they go straight through to a more interactive version of the same data.
I have a PageView with a large amount of pages in my app. Each of the pages is very complex with a PageView and its own pages.
I'm new to Flutter and my first hunch is that it needs optimization. So within the build() function of the outmost PageView I check the index and only make full page for current, previous and the next page(I guess swipe animation needs current page and the page next to it built ahead). For other pages I just give it an empty Container().
Is this necessary and the right thing to do? I felt this is an obvious optimization that the Flutter should do, but I can't find any related discussion online. Any suggestions are appreciated!
Flutter's PageView is lazily calling itemBuilder you provided. For an index it's called only when the page is really needed and you don't need to do anything more. But for further improvements you can make your view hierarchy simpler and prevent unnecessary build method calls. Here you can read more about Performance best practices.
No, it's not. ListView, GridView, and widgets alike are already optimized to build and render only what is needed in the moment. You get a hint of that in the PageView.builder description :
Creates a scrollable list that works page by page using widgets that
are created on demand
I think the difference between a regular PageView and a PageView.builder is that PageView initializes all children at startup, while PageView.builder are initialized lazily.
This is a Flutter Specific Query.
I Want to achieve the Layout Referenced in the Image above. Two Tabs
Below a Container.
The Tabs can be switched using Swipe Animation like that in a
Page View.
The Tabs Contain Dynamically Generated Widgets from Provider.
The Entire Page along with the Fixed Container must be
Scroll-able.
When Switching between the Tabs the fixed container should stay
in place and only tab Content(Column of Widgets) should swipe
left and right.
What I've Tried :
Using a Parent List View and Nesting the Fixed Container Child
and Using Tab Bar to switch the Widget using Animated Switcher and
Slide Animation. Here the Problem is i cannot swipe left and right
and create the Page View like Effect. I also tried Nesting Page-View
inside List-View but since the Page-View does not have a fixed height
( because the tab contents are dynamically generated ).
A few many more concepts i tried to tackle but the issue every time was
that the tab contents are not having a fixed height.
I really want to achieve this Layout and i want to know if there's any way.