I am new in flutter I can't understand that is infinity size render in flutter
If I use container with infinity width then it will render but in box constraints documentation infinity size can't render
This is because there is something constraining the widget, when you set as an example:
Container(
width: double.infinity,
),
it will try to take an infinity size, which usually will throw an error to you, but it's constrained so it takes the max possible width.
The Container widget is built on top of different multiples widgets such as ConstrainedBox, DecoratedBox, Align, LimitedBox... , the ConstrainedBox defaults to the BoxConstraints.expand(), check it's source code:
// ...
child: ConstrainedBox(constraints: const BoxConstraints.expand()),
);
but if you check also the Scaffold source code :
// ....
final BoxConstraints fullWidthConstraints = looseConstraints.tighten(width: size.width);
so trying to expand that Container even within infinity, will expand it at maximum on the fullWidthConstraints which is, in this case, the screen's width.
Related
Because Flutter Stepper is scrollable, it can't be set the step content to fill its height.
I want to make a layout like this
While I'm getting this layout
I've used SizedBox with fixed height, but it's incorrect way while screens have different height values.
You can use SizedBox , just specify a non-fixed height and get the current screen height via
MediaQuery. of(context). size. height
this is how it works normally regardless of the screen size
Step(
isActive: currentStep >=0,
title: Text('Account'),
content: SizedBox(
height: MediaQuery. of(context). size. height - 300,
child: Text("sdf"),),
),
I and my team are working on a different screen size emulator. While integrating we notice that some properties are overlapped by others, and some are not visible only. So how we can make our app adaptive to different screen sizes. Went through the mediaquery() widget but I didn't understood much.
Using MediaQuery class:
MediaQueryData queryData;
queryData = MediaQuery.of(context);
MediaQuery: Establishes a subtree in which media queries resolve
to the given data.
MediaQueryData: Information about a piece of media (e.g., a
window).
To get Device Pixel Ratio:
queryData.devicePixelRatio
To get width and height of the device screen:
queryData.size.width
queryData.size.height
To get text scale factor:
queryData.textScaleFactor
Using AspectRatio class:
From doc:
A widget that attempts to size the child to a specific aspect ratio.
The widget first tries the largest width permitted by the layout
constraints. The height of the widget is determined by applying the
given aspect ratio to the width, expressed as a ratio of width to
height.
For example, a 16:9 width:height aspect ratio would have a value of
16.0/9.0. If the maximum width is infinite, the initial width is determined by applying the aspect ratio to the maximum height.
Now consider a second example, this time with an aspect ratio of 2.0
and layout constraints that require the width to be between 0.0 and
100.0 and the height to be between 0.0 and 100.0. We'll select a width of 100.0 (the biggest allowed) and a height of 50.0 (to match the
aspect ratio).
//example
new Center(
child: new AspectRatio(
aspectRatio: 100 / 100,
child: new Container(
decoration: new BoxDecoration(
shape: BoxShape.rectangle,
color: Colors.orange,
)
),
),
),
Also you can use:
LayoutBuilder
FittedBox
CustomMultiChildLayout
MediaQuery is a good option for this scenario
for example, I just want to create a container with half of the available width and height of my mobile screen
class MyContainer extends StatelessWidget {
#override
Widget build(BuildContext context) {
final size = MediaQuery.of(context).size;
return Container(
color:Colors.orange,
width: size.width/2,
height: size.height/2
);
}
}
I'm building an expansible card in flutter, which I wanto to animate. I want the parent Container to have a limited height while the card is collapsed, and to have whatever height is necessary for the child when it's expanded. I can reach this result using maxHeight: double.infinity:
Container(
alignment: Alignment.topCenter,
clipBehavior: Clip.hardEdge,
constraints: isExpanded
? BoxConstraints(maxHeight: double.infinity)
: BoxConstraints(maxHeight: 76),
decoration: BoxDecoration(),
child: widget.child,
),
)
But whatever maxHeight value I use other than double.infinity causes the parent to have that exact height, instead of just having the height needed by the child. I can't use double.infinity because that's not animatable. I've tried following this answer's tips, but whatever I wrap the child with, the parent always grows. I've tried changing the child, but even if I use maxHeight on the child itself, the parent always grows to the defined maxHeight.
Why does this happen? Shouldn't maxHeight only cause the parent to expand if needed? How come it works correctly with double.infinity, but doesn't with anything else?
Also, I have tried reaching this result with AnimatedSize, it sort of works. When it is expanding, it works perfectly, but when the child is collapsing, it collapses instantly, and the AnimatedSize's animation follows after.
Edit:
I see what you mean, you want to use AnimatedContainer, but in order to be animated like you want it, it requires you to specify the height. double.infinity won't do in this case, the error message you're getting is correct.
There are ways to get widget height.. I suggest you check this answer: https://stackoverflow.com/a/49650741/7248289
Also, this one might help: https://stackoverflow.com/a/54173729/7248289
I'm creating a widget that presents a Stack inside a Container. Inside the Stack there is a dynamic Column inside a Positioned widget, which sticks the Column to the Bottom.
I am trying to wrap the Stack in a SingleChildScrollView, that if the dynamic Column will have lots of children it will be able to scroll.
But after I add the scroll view I get this error message:
RenderStack object was given an infinite size during layout.
A scrollView doesn't have height, it will use infinite height for it's children. So the stack should be wrapped in a sizedBox widh a known height in case that you want that. If you want the stack to fill the screen then remove the singleChildScrollview completely. And if you want the stack to be scrollable from the inside. Just add SingleChildScrollView inside the stack
return Scaffold(
body: Container(
color: Colors.blue[100],
child: Stack(
children: [
Positioned.fill(child: SingleChildScrollView(child: MyColumn()))
],
),
),
);
EDIT 1:
Ok the problem is the layout itself. Since you only use the stack to position the image. And you know the widht and height of the image, and the background shape fills all the items. We could
Isolate the stack only to the image, and use padding and some calculation to have the layout build in a similar way.
Then render everything else inside a normal column
My implementation https://dartpad.dev/230b14d8f0b22b45929a75c208786257
From the RenderStack documentation:
First, the non-positioned children (those with null values for top, right, bottom, and left) are laid out and initially placed in the upper-left corner of the stack. The stack is then sized to enclose all of the non-positioned children. If there are no non-positioned children, the stack becomes as large as possible.
Since all of your Stack's children are positioned, Stack will match the maximum size constraint passed down by the SingleChildScrollView. This size has infinite height, so the Stack is forced to have infinite height as well.
To fix this, you will need to find another way to accomplish what you want. One option that comes to mind involves a ConstrainedBox providing a minimum height (obtained from a LayoutBuilder), a non-positioned Column, and a bottomCenter alignment on the Stack itself. This is similar to the first code sample in the SingleChildScrollView documentation:
LayoutBuilder(
builder: (context, constraints) {
return SingleChildScrollView(
child: ConstrainedBox(
// This ensures that the Stack fills the entire viewport,
// even if the Column is small.
constraints: BoxConstraints(
minHeight: constraints.maxHeight,
),
child: Stack(
// Place the only non-positioned child (the column) at the bottom
alignment: Alignment.bottomCenter,
children: [
Column(
mainAxisSize: MainAxisSize.min,
children: [ /* ... */ ]
)
]
)
)
);
}
)
I want to have a line that has 100% parent height, the line should has a fluid height following it's parent's height. the parent's height would be dynamic because every content has it's own height. Just like in Path app.
This is my app, currently I'm setting the height as a constant, how to make it dynamic following it's parent's height? :
Container(
width: 1,
color: Colors. redAccent,
height: 300, // <-- this height
)
try to use the Expanded Widget which uses the available space. you just have to definewhat is the available space here
Expanded(
child: Container(
color: Colors.amber,
width: 100,
),
),
here, if you dont put something on top of the expanded, it will take all the screen
and if not on the bottom, it will reach the bottom of the screen.
it takes the whole free space.
I solved this by adding container and add border left :)