Develop Reference

Flutter Navbar UI Border Radius

I am currently working on my first mobile app, and need some help with some of the code pertaining to my navbar. I have watched some videos and read some docs on using the tag BottomNavigationBar to better sort and make my navigation bar but I am struggling to make it look how I want. Right now I have the default navbar it gives you with a different background color but I added padding to give it space from the edges of the screen. I now want to round the corners but it seems wherever I try to apply a border-radius it just doesn't work. Any idea how I can go about rounding these corners to give a good-looking floating navbar look? Thanks!
Current Navbar Look
Widget build(BuildContext context) {
return Scaffold(
// ignore: prefer_const_literals_to_create_immutables
bottomNavigationBar: Container(
padding: const EdgeInsets.all(8.0),
child: Material(
borderRadius: BorderRadius.circular(10),
color: Colors.black,
child: BottomNavigationBar(
fixedColor: Colors.white,
unselectedItemColor: Colors.white,
backgroundColor: Color.fromARGB(255, 27, 27, 27),
currentIndex: _selectedIndex,
// ignore: prefer_const_literals_to_create_immutables
items: [
BottomNavigationBarItem(icon: Icon(Icons.home), label: 'Home'),
BottomNavigationBarItem(icon: Icon(Icons.add), label: 'Add Friend'),
BottomNavigationBarItem(icon: Icon(Icons.search), label: 'Search Friends'),
],
),
),
),
);
}

Flutter: How to prevent an container overflowing inside a padding

The Problem
I have a card that contains a row of two elements, the second one being a column of two texts. One of the texts can be long, so the column-element itself can overflow.
Coming from CSS, a "width: 100%" would usually be enough here.
What I already tried
I learned you could wrap the column with something like Expanded or Flexible, but it leads the text to become invisible (and the overflow still existing).
I am not sure where exactly I have to put the Flexible/Expanded.
I looked into similar questions and there was always an "Expanded", but I could not apply any of said solutions to my layout so far.
Question
What is the cleanest way to get the outlined box to be only as wide as the padding should allow?
Code
#override
Widget build(BuildContext context) {
return (Card(
child: InkWell(
onTap: () {
print("tab" + name);
},
child: Padding(
padding: const EdgeInsets.all(16),
child: Row(
children: <Widget>[
ClipRRect(
borderRadius: BorderRadius.circular(25),
child: SizedBox(
width: 50,
height: 50,
child: Image(
image: NetworkImage(imageUrl),
),
),
),
Padding(
padding: const EdgeInsets.all(16),
child: Container(
decoration: BoxDecoration(
border: Border.all(width: 1, color: Colors.purpleAccent),
),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(
name,
overflow: TextOverflow.ellipsis,
style: const TextStyle(fontWeight: FontWeight.bold),
textAlign: TextAlign.left,
),
Text(
description,
overflow: TextOverflow.ellipsis,
textAlign: TextAlign.left,
),
],
),
),
),
],
),
),
),
));
}

You can surround the Padding widget inside your Row with an Expanded widget - The child of Expanded will then size itself to the space available.
For some additional context, Rows and Columns are both Flex widgets. Flex widgets layout their children along an axis, and the size of this axis is unbounded by default. Even though the widget "knows" how much space it has available on the display, it doesn't pass that information along to its children, so the children are free to take whatever size they want, which means they can potentially overflow the container.
An Expanded widget can only be placed as a direct child of a Flex widget, and it automatically takes up a given proportion (given by the flex property) of the space available to it (by default that will simply be all of the space which is not taken up by other widgets in the children list).
So essentially, Expanded will take up as much space as the parent widget has available, and then will constrain it's child to be no larger than that (along whichever axis pertains).
The link above to the Flex documentation has more info.

Background Image

return Stack(
children: <Widget>[
Image.asset(
'assets/logo/greenframe.png',
height: MediaQuery.of(context).size.height,
width: MediaQuery.of(context).size.width,
fit: BoxFit.fill,
),
...
I'm using this code for using a background image on my app. It is a rectangle frame. It works okay with my Redmi Note 8 screen but on another phone with a different size of the screen, it's not looking good. Not fitting the screen. Is there a way to fix this?

How can I set the size based on screen size?
You can use MediaQuery.of(context).size to get a responsive design for all screen sizes. For example, defining the size of the icon button will look like this:
IconButton(
iconSize: MediaQuery.of(context).size.height * 0.03, // Here!
icon: Icon(
Icons.arrow_back,
color: Colors.black,
),
onPressed: () => Navigator.pop(context),
),
Read more from here.

How do I set the background colour/image to be stacked above another expanded widget? Or is there another way

Currently the only way I could make this kind of curved effect would be through making 2 container, making 1 a child of another and making 1 container's colour into the background colour.
However I cannot replicate this effect if the background is an image. Could anyone assist?
Example of the code I use:
Scaffold(
body: SafeArea(
child: Column(
children: <Widget>[
Container(
height: 100,
color: Color(0xFF0D6068),
),
Expanded(
child: Container(
color: Color(0xFF0D6068),
child: Container(
decoration: BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.only(
topLeft: Radius.circular(50),
topRight: Radius.circular(50),
)),
),
))
],
)),
);

You can make use of a Stack widget to achieve this, such that the background color or image would be at the back then the curved container would be stacked on it. Here is an example code.
Stack(children <Widget> [
Image.asset(''),
Container()
]
)
Instead of using an image asset, you can make use of BoxDecoration with the decoration parameter of a container. The BoxDecoration has an image parameter where you can provide your image with a DecorationImage() widget.

Flutter mask a circle into a container

I want to add a circle effect over a container, but I want the circle to not extend the dimensions of the container, but instead get clipped by it. This is what I'm trying to achieve:
As you can see the white circle naturally would extend the red container but instead, I'm trying to make it stay into the borders. How can I do it?

The simplest way to do this is to using an overlap and cliprect.
class OverlapSquare extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Container(
height: 200,
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(10),
color: Colors.red,
),
child: ClipRect(
clipBehavior: Clip.hardEdge,
child: OverflowBox(
maxHeight: 250,
maxWidth: 250,
child: Center(
child: Container(
decoration: BoxDecoration(
color: Colors.white,
shape: BoxShape.circle,
),
),
),
),
),
);
}
}
The OverFlowBox allows the circle to draw outside the bounds of its parent, and then the cliprect cuts it back to the edge.
Just an FYI - on my device I'm getting a tiny red line at the top & bottom of the white circle. I'm fairly sure that's a recently-introduced bug in flutter as I'm also seeing something similar if I put a white border around the container. I've raised an issue on github for that.

ClipRRect worked best for me.
See reference video: https://www.youtube.com/watch?v=eI43jkQkrvs&vl=en
ClipRRect(
borderRadius: BorderRadius.cirular(10),
child: myContainerWithCircleWidget,
);