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.
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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'm trying to live copy the content 1:1 to another widget. Is there some Widget that already has this functionality?
For some Context: I have the Surface Duo and the hinge blocks some of the content in the middle (under the hinge) when spanning the app across both screens. There seems no way to avoid that, so I'm trying to build an app that prevents this as follows:
Build a custom browser
Render at full screen resolution
Copy content to second widget
Overlay/stack second widget on top of first widget, clip/crop and move it so that the content continues without loss of information.
I'm happy to elaborate on the problem if you have any questions. Of course any other solution that you might come up with is appreciated (for example, if there is some way to skip rendering a Widget for part of the screen).
Thanks in advance and best,
Daniel
I'm trying to implement a breadcrumb widget in my Flutter app and I would like to achieve the following behavior:
Let's say the red outlined area is the space I have for my breadcrumb and that each element of the breadcrumb has a different width. The breadcrumb should be responsive, i.e. it should show elements as long as there is enough space to show them, otherwise, remove some of the elements and add that '...' button in the middle. Clicking on that button shows an overlay that contains the removed elements.
Now, I want to know how much space each breadcrumb element will take before it is laid out on the screen. Only then, I can decide whether there is enough space for it to be shown in the breadcrumb or it should be part of the '...' button.
I tried to use CustomMultiChildLayout which gives you information about how much space a widget takes after laying it out. It also needs to layout each child once, which makes it unuseful in my use case.
P.S: Think about the breadcrumb used in the apple documentation. That's the same behavior I want to achieve.
Short answer, you can't.
You were already using CustomMultiChildLayout, that's good, it shows me that you should have some basic understanding of how flutter rendering pipeline works. Then it should be clear to you of the 3 steps: parent passes down constraints, child reports its size, parent decides where to place the child. So in short, again, you cannot get children's size before layout.
Now move on to the thing you want to achieve. I agree CustomMultiChildLayout cannot achieve what you want to do, but not for the reason you listed. The main problem is CustomMultiChildLayout forces you to layout each child once, and then position them. You must position each child, you cannot skip a child if you don't like it (too big), and you cannot fabricate new stuff that's not your children. If you could achieve these 2 things, then getting children's size after layout isn't going to be a problem.
To achieve those, the easiest way is to use CustomPaint, if everything you need to do, are text-based or just simple shapes. Use TextPainter to layout a text, get its size, then decide whether to paint that text, or paint "..." (skip a child and fabricate your own) instead. You can search on how to do these things easily, but mostly search on TextPainter.
If you want to paint other widgets as your children, and optionally skip some of them while fabricating others, you should write your own RenderObject. That is one level lower than "widgets-level". If you have never done that before, you can research on that topic as well.
I'm trying to find a way to check the visibility of a Flutter widget when it's either off screen or when it's obscured by another, for example Drawer, Dialog or BottomSheet.
visibility_detector helps with checking whether it's on the screen or not but does not work with the second use case (known limitation).
Is there a lower lever api that I can use to check whether a widget is actually visible to the user?
My use case: I'm adding a widget to the Overlay when something external happens (similar to Tooltip but not on long press). If the user opens for example the Drawer, the widget will appear on top. I want to detect that the child is not visible and delay or cancel the action.
Do I understand your problem?
You have a widget you want to always be on top?
You want the user to interact with that widget first before doing other things?
Use design patterns to make coding easier, your users will thank you.
You can show a Dialog on-top of other widgets with the showGeneralDialog or showDialog functions. Because Dialogs are a design-pattern used in many apps, users will already know how to use them.
Define app behavior with explicit state.
It is too hard to derive app behavior from rendered UI, not all devices are the same size and shape. This means you should try to write a variable that describes your situation and then write the code you need to make that variable's value correct. It sounds like you want a variable like bool overlayIsShowing.
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.