Develop Reference

How to make a background gradient fill the screen in a SingleChildScrollView? (but not ConstrainedBox)

What is the best way to have a background gradient fill the entire screen, all while being in a SingleChildScrollView? I would like the screen to scroll only when necessary (when the items and bottom text overflow the screen). Note the Back button is a FAB.
Note: I have tried ConstrainedBox (but the scroll is weird when there's no overflow in the listview)
What's the best way to 1) fill the background completely, and 2) have scrolling activity only activate when the listview overflows?
My code:
Widget body() {
return SingleChildScrollView(
child: Container(
decoration: background(),
child: Column(children: [
listViewReminderBuilder(),
SizedBox(height: 10),
Container(
padding: EdgeInsets.all(5),
child: bottomText()),
SizedBox(height: 10),
])));
}
BoxDecoration Background() {
return BoxDecoration(
gradient: LinearGradient(
begin: Alignment.topRight,
end: Alignment.bottomLeft,
colors: [
topColor,
bottomColor,
],
));
}
This is the result of the above code is shown below. The scroll works as I'd like (only scrolls when there's an overflow of listview items), but obviously the background doesn't fill the screen.
Many solutions online led me to the ConstrainedBox. My code and result is as follows:
Widget body() {
_screenHeight = MediaQuery.of(context).size.height;
return SingleChildScrollView(
child: Container(
decoration: background(),
child: ConstrainedBox(
constraints: BoxConstraints(minHeight: _screenHeight),
child: Column(children: [
listViewReminderBuilder(),
SizedBox(height: 10),
Container(
padding: EdgeInsets.all(5),
child: bottomText()),
SizedBox(height: 10),
]))));
}
// background() was the same
The result. In this case, the background nicely fills the screen, but the screen is always scrollable and looks weird if the listview items aren't overflowing.
What's the best way to 1) fill the background completely, and 2) have scrolling activity only activate when the listview overflows?

first of all: wraping ListView with SingleChildScrollView is not good practice.
workaround:
use container only for background. by setting width infinity to fill entire screen.
no need to wrap with SingleChildScrollView if you have a ListView. just use Expanded widget.
Widget body() {
return Container(
width: double.infinity,
// here you can set height if you want.
// but since we use Column,by default it will expand the maximum height.
decoration: background(),
child: Column(children: [
// using Listview will make you widget not overflowing.
// wrap with expanded to make it fill available screen.
Expanded(child: listViewReminderBuilder(),),
SizedBox(height: 10),
Container(padding: EdgeInsets.all(5), child: Text('Back')),
SizedBox(height: 10),
]));
}
i just tried on dartpad. and it works fine.

How do I prevent the background image from shrinking when a value is entered from the phone keyboard in Flutter?

View before the keyboard is seen
The view after the keyboard is seen
I want the background image to always stay at the size before the keyboard is seen.
return Scaffold(
body: Container(
decoration: const BoxDecoration(
image: DecorationImage(
image: AssetImage('assets/back.png'),
fit: BoxFit.cover,
),
),
alignment: Alignment.center,
padding: const EdgeInsets.fromLTRB(50, 100, 70, 0),
child: Column(
mainAxisAlignment: MainAxisAlignment.start,
children: [
Center(
child: TextFormWidget(form: name, hint: 'Name',),
),
SizedBox(
height: 15,
),
TextFormWidget(form: surname, hint: 'Surname'),
],
),
),
);

resizeToAvoidBottomInset on scaffold
If true the [body] and the scaffold's floating widgets should size themselves to avoid the onscreen keyboard whose height is defined by the ambient [MediaQuery]'s [MediaQueryData.viewInsets] bottom property.
For example, if there is an onscreen keyboard displayed above the scaffold, the body can be resized to avoid overlapping the keyboard, which prevents widgets inside the body from being obscured by the keyboard.
Defaults to true.
Also you might also like to wrap Scaffold with SafeArea to get view after statusBar.

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.

How to increase the overall thickness of a banner in flutter?

I'm making a flutter app where there's a gridview of cards that shows details of different items in a list. In the top right corner of the card I added a banner using the banner widget that shows the current status of the item.
This is what the banner looks like. But I want to move the banner a bit more to the corner as well as make it more wider.
Card(
elevation: 1.0,
child: ClipRect(
child: Banner(
textStyle: TextStyle(color: Colors.white),
message: 'OPEN'
location: BannerLocation.topEnd,
color: const Color(0xFF0db3ae),
child: InkWell(
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Text('......')
),
onTap: () {},
),
),
),
);
This is the basic structure of the code I used to make the cards and to make sure the banner wraps around the card. But i can't find a way to increase it's width or move it a bit more to the corner.

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.