How to properly manage parent:child relationships - flutter

Card, by default, assumes the size of its child. So, if we want to change the size of that card, then we also need to change the size of its child.
Text, on the other hand, is a widget. Which, by default, only takes as much space as this text needs. Therefore, if you want to change the size of Text, you need to also change the size of its parent. Since the Card depends on the child and the Text depends on the parent.

Card by default does not have any height or width. The width/height depends on the Child or the Card. In the screenshot, the child here is Text() Widget. The Text widget takes as much space as it's font size. So more the font size is, the larger will be Card.
The last part of the explanation is incorrect. You can't change parent size here as "Card" widget does not has any size properties. So if u want bigger card and small text, use "Container" Widget instead of Card. Almost all developers use Container only to create Card. Container has more feature then a card has.
Container(
height: 100,
width: 100,
child: Material(
elevation: 5,
child: Text("Chart!"),
),
)

Related

Make widget always expand to screen border

Is there a way to make a widget, for instance a Container, always expand to a screen border, not dependent of a specific widget tree structure?
Containers impose constraints on their children so you can't make a child's width bigger than its parent when it is a container
some tips :
you can use the Expanded widget to take all the remaining space
to take all the size of the screen you can use width: double.infinity
As they said already, in Container() you can use width: double.infinity or width: MediaQuery.of(context).size.width. But for this, the parent of Container can't have a size smaller than the screen.

How to clip a variable sized widget into a fixed size in flutter?

I'm having a bunch of widgets (dynamically sized) in a ListView, and I want each of those widgets to be exactly 300 pixels. How is it possible?
(Note: Using SizedBox along with BoxFit.contain makes some of widgets too small; I want it to be cropped).
Use BoxFit.cover instead of contain to crop it. BoxFit.contain will shrink it to fit in its parent.
For more info check this out
https://api.flutter.dev/flutter/painting/BoxFit-class.html

How to set the height of a widget dynamically in flutter?

Container(
height: min(
widget.order.products.length * 20.0 + 10,
100,
),)
widget.order.products.length => will return me the list of dynamic products.
While viewing the list of these products, I want the set the height of the container dynamic which I'm not able to do with the "min" function.
Can anyone help me.
Thanks in advance.
This can be done by using an IntrinsicHeight:
https://api.flutter.dev/flutter/widgets/IntrinsicHeight-class.html
A widget that sizes its child to the child's intrinsic height.
This class is useful, for example, when unlimited height is available and you would like a child that would otherwise attempt to expand infinitely to instead size itself to a more reasonable height.
The constraints that this widget passes to its child will adhere to the parent's constraints, so if the constraints are not large enough to satisfy the child's maximum intrinsic height, then the child will get less height than it otherwise would. Likewise, if the minimum height constraint is larger than the child's maximum intrinsic height, the child will be given more height than it otherwise would.
This van be put Around things like a listView, Column etc.

Flutter - How to remove margin under GridView?

I get a strange margin under my GridView:
This image is from an IOS simulator, here's how it looks on a smaller screen on Android where the margin appears to be gone or a lot smaller:
Here's the code:
Column(
children: [
GridView.count(
shrinkWrap: true,
crossAxisCount: 8,
children: tiles
),
Text('mamma')
]
)
Each element in the grid (tiles) is an EmptyTile widget:
class EmptyTile extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Container(
decoration: BoxDecoration(
color: bgColor,
border: Border.all(color: borderColor)
)
);
}
}
I really can't figure out what this margin is or where it comes from, whether it has something to do with shrinkWrap or something else.
How can I remove this margin?
EDIT:
As requested here's the fullscreen images without the simplified example.
IOS:
Android:
Try this. by default it has padding and you should set padding to zero.
GridView.builder(
padding: EdgeInsets.all(0),
The difference in layout you experience comes from a combination of things:
How GridView manages its size.
How widgets are placed in a Column.
GridView tiles and size
When you build a GridView, its width and height are implicitly deduced from the crossAxisCount parameter and the constraints given by its parent.
The constraints are the limits in size in which the widget is allowed to draw.
The crossAxisCount defines how many tiles should fit in one line (row or column). Depending on its scrollDirection, it will either try to fill all the available width or height. By default this direction is set to Axis.vertical, which means that the width will be filled.
So when we come back to your example, this means that the size of each tile will depend on the width of the Column containing your grid, divided by the number of tiles you set in crossAxisCount. This size will be both the width and the height of every tile in your GridView.
Once Flutter knows the size of each of your tiles, it sets them on each row, until all tiles are placed or there isn't any available space.
Column layout
Now that we know more about GridView, we need to understand how Column builds its layout.
Columns allocates space to each widget in its children, following an algorithm best describes in the docs.
tl;dr:
Your GridView will only fill its own height in the Column, leaving the rest as free space. This is why you get empty space in your Column.
Possible fix
I actually don't really see how this is a problem. GridViews are supposed to only extend to display their children, so it totally makes sense for it to stop when it completed.
The thing is, most of the times this ind of grids are not used with a finite list of children, and more likely with a growing list.
If you only want to have one line of tiles, that will extend using the available space, you could use a simple Row.
If you want multiple lines of tiles, with non-square tiles, you need to dive a little deeper into GridView.custom.
Edit after question was updated with more screenshots:
It is possible that you need to rethink your layout so that the player panels are in the same Column than the game board. You will have a much better control over the layout this way.

What does actutally Bottom overflowed by 123 pixels mean in flutter

I am learning flutter and currently switched from android to flutter.In flutter i mostly get an error something like
bottom overflowed by 234 pixels or renderbox overflowed by 340 pixels.And i fixes that problem by increase the height of the widget.If so then how to know that what much size giving to widget.I mean in android we can declare the height of the layout to be wrap content and its works perfectly.Please explain me that how can i avoid this situation because if i fixes the issue by changing the height of widget in one device then in devices of other screen sizes if throws same error ?Here is a image which throws an error.Ignore the red error , see the error in below screen.Thanks in advance.
!https://imgur.com/a/PsZzeMp
If you want to give fixed width and height to your widgets wrap it with SizedBox.
You can specify fixed width and height and you child widget will be the exact dimension.
If you want one of the dimension fixed and the other as big as the parent widget, you can try something like this:
SizedBox(
width: double.inifinity,
height: 50.0
child: Conttainer()
)
If you are worried about giving fixed dimensions. You can give the height or width according to the ratio of the screen size. You can get the height and width of the screen like this:
double width = MediaQuery.of(context).size.width;
Use the above value to give the width to your widgets like below:
Container(
width: MediaQuery.of(context).size.width * 0.8,
height: 100,
)
To answer question in the comment. You can do the following to wrap the text with dynamic content.
ConstrainedBox(
constraints: BoxConstraints(
maxWidth: 100
),
child: Text(
'ADASFASF ssss'
),
)
The above code will wrap the text to next line if the text widget is more than 100 pixels wide. As we don't have any constraints on the height.
Overflow happens when the minimum size of a child widget is bigger than the parent's constraints (width and/or height).
Which means you can:
make the parent widget bigger (eg: SizedBox(height:, width:,))
make the child smaller (eg: using a FittedBox(fit: BoxFit.scaleDown) widget)
Though the first method will not allow you a size bigger than the parent's parent widget. It should be enough to build the children relatively to their parents and not the other way.
In your case, it seems like you text + image widget is taking a little too much space. I recommend wrapping it in a FittedBox that will scale down the child widget until it fits in you bottom bar.
FittedBox(
fit: BoxFit.scaleDown,
child: _buildChildWidget(),
)
You can then wrap it in other widgets to build the layout you want (Row, Expanded, Flexible, LayoutBuilder, ...).
As the overflow issue usually happens because text or images are too big. A good exercise is trying to make your app work while setting text size to the maximum value allowed by the accessibility options of your device. You can do the same with images by setting an image size relative to your text size for example.
Paddings and margins can also cause problems because they leave less space for the child widget.