I want to display some widgets in a Wrap, and if the widgets are too many to fit on one row, I want to display different widgets (more compact versions of the normal widgets).
How can I achieve this, without resorting to manual measurements of screen width and children? Is there any built-in way to do this with a Wrap or some other widget?
What if with the compact version, the row is still full. Do you want to display the children in multiline then or wrap them with the next line? If it's the latter, then I think it's best to use Wrap from the beginning.
Another practical way is to make the child adaptable as well, by using FittedBox or make it scrollable horizontally by using SingleChildScrollView or ListView.
There can be other scenarios when it's better to show just 4-5 children that's enough to fit a row. Then have a button allowing user to navigate to a detail screen display all the children in a grid or list.
Related
Problem summary
I'm building simple animation in which, simply, a panel expands to the right on a onTap event. The layout can be summarized as follows:
The panel has many tiles. Each tile has its own:
leading icon
title text
trailing icon
Each tile, when expanded, shows the three widgets above
Each tile, when shrinked, just shows the leading icon
The panel is scrollable to hold many icons such as these
At the end of the panel there's a simple icon which, when tapped, triggers the "expand" or "shrink" animation
The animation is built with an AnimatedContainer on the panel and a SizeTransition on the single tiles (via one single controller on the parent class)
The problem is simple: when the tiles shrink, their inner text overflows in the row.
Sample code
I just made this reproducible example on DartPad.
The obvious solution isn't helping me out
The most obvious solution is to simply wrap the Text inside a Flexible Widget: this advised by Flutter's docs and it makes sense, but unluckily it completely breaks my Layout.
Flexible introduces a flex factor that in this context is 100% unwanted.
I want my leading icons to be always at the end of the row, so my Spacer widget should "prevail" there.
I can't just play with flex factors there, as it would unintendedly hide text depending on its value.
Another code smell
Another thing I really don't like is the fact that I have to build a controller on the parent class, but I'm not actually using it on the parent class (I'm just exploiting it so I can give it to the children).
I'm new to animations in Flutter so I'm kinda confused on how I should orchestrate the whole thing here.
Any help will be appreciated / upvoted / accepted. Thank you!
As far as I understood you in a right way you just need set sizes for Row inside of SizeTransition instead of Container sizes
Here is your modified sample https://dartpad.dev/?id=a2408d29a1e8c6ce7a1cef8f21e7491d
I'd try an OverflowBox or a FittedBox (wrapping your text), depending on the result you want to achieve.
Consider the case that I have 3 adjacent list view with each list view having a sized widget of some height. Each list view has around 24 child items. I'm trying to scale the widget using onScaleUpdate in GestureDetector.
onScaleUpdate I want to change the height of each child item of all the 3 listviews.
Is rebuilding all child better or should I rebuild the whole widget?
As #Yeasin Sheikh pointed out, using ListView.builder is good because it builds only the needed children (the ones inside the screen and just a few ones outside as precaution). And as to actually answering your question, I'm no Flutter expert, but using ListView.builder I don't think it makes that much difference, Flutter is intelligent enough to solve this by itself.
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 try to solve the following problem: I want to have a dynamically generated set of cards widgets which should be layed out horizontal and wrap the line when the card is getting too big:
I was thinking of a ListView.builder but this can either go horizontal or vertical. More, a gridview seems also not the best option as I have no fixed columns or rows. Is there any way in doing so or exists there maybe a widget I am not aware of currently?
I use GridView in my Flutter's app. Size my GridView is 30x4(with different widgets).
I need to update one widget in my gridView. I have two solutions and I need to choose the best.
Update all GridView. It is easy but I think this is not optimal (rebuild the entire grid for one change).
Update one widget. it is more complicated. but I know how to do it. This is a similar example.
what do you advise?