Ekhlass/Flutter_Documentation · Datasets at Hugging Face

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it’s the opposite. The confirmation button is
placed at the end of the row (right side).This can be easily handled in Flutter using the
TextDirection property on Row:
<code_start>TextDirection btnDirection =
DeviceType.isWindows ? TextDirection.rtl : TextDirection.ltr;
return Row(
children: [
const Spacer(),
Row(
textDirection: btnDirection,
children: [
DialogButton(
label: 'Cancel',
onPressed: () => Navigator.pop(context, false),
),
DialogButton(
label: 'Ok',
onPressed: () => Navigator.pop(context, true),
),
],
),
],
);<code_end>
<topic_end>
<topic_start>Menu bar
Another common pattern on desktop apps is the menu bar.
On Windows and Linux, this menu lives as part of the Chrome title bar,
whereas on macOS, it’s located along the top of the primary screen.Currently, you can specify custom menu bar entries using
a prototype plugin, but it’s expected that this functionality will
eventually be integrated into the main SDK.It’s worth mentioning that on Windows and Linux,
you can’t combine a custom title bar with a menu bar.
When you create a custom title bar,
you’re replacing the native one completely,
which means you also lose the integrated native menu bar.If you need both a custom title bar and a menu bar,
you can achieve that by implementing it in Flutter,
similar to a custom context menu.<topic_end>
<topic_start>Drag and drop
One of the core interactions for both touch-based and
pointer-based inputs is drag and drop. Although this
interaction is expected for both types of input,
there are important differences to think about when
it comes to scrolling lists of draggable items.Generally speaking, touch users expect to see drag handles
to differentiate draggable areas from scrollable ones,
or alternatively, to initiate a drag by using a long
press gesture. This is because scrolling and dragging
are both sharing a single finger for input.Mouse users have more input options. They can use a wheel
or scrollbar to scroll, which generally eliminates the need
for dedicated drag handles. If you look at the macOS
Finder or Windows Explorer, you’ll see that they work
this way: you just select an item and start dragging.In Flutter, you can implement drag and drop in many
ways. Discussing specific implementations is outside
the scope of this article, but some high level options
are:Use the Draggable and DragTarget APIs
directly for a custom look and feel.Hook into onPan gesture events,
and move an object yourself within a parent Stack.Use one of the pre-made list packages on pub.dev.<topic_end>
<topic_start>
Educate yourself on basic usability principles
Of course, this page doesn’t constitute an exhaustive list
of the things you might consider. The more operating systems,
form factors, and input devices you support,
the more difficult it becomes to spec out every permutation in design.Taking time to learn basic usability principles as a
developer empowers you to make better decisions,
reduces back-and-forth iterations with design during production,
and results in improved productivity with better outcomes.Here are some resources to get you started:
<topic_end>
<topic_start>Update the UI based on orientation
In some situations,
you want to update the display of an app when the user
rotates the screen from portrait mode to landscape mode. For example,
the app might show one item after the next in portrait mode,
yet put those same items side-by-side in landscape mode.In Flutter, you can build different layouts depending
on a given Orientation.
In this example, build a list that displays two columns in
portrait mode and three columns in landscape mode using the
following steps:<topic_end>
<topic_start>
1. Build a GridView with two columns
First, create a list of items to work with.
Rather than using a normal list,
create a list that displays items in a grid.
For now, create a grid with two columns.
<code_start>return GridView.count(
// A list with 2 columns
crossAxisCount: 2,
// ...
);<code_end>
To learn more about working with GridViews,
see the Creating a grid list recipe.<topic_end>
<topic_start>
2. Use an OrientationBuilder to change the number of columns
To determine the app’s current Orientation, use the
OrientationBuilder widget.
The OrientationBuilder calculates the current Orientation by
comparing the width and height available to the parent widget,
and rebuilds when the size of the parent changes.Using the Orientation, build a list that displays two columns in portrait
mode, or three columns in landscape mode.
<code_start>body: OrientationBuilder(
builder: (context, orientation) {
return GridView.count(
// Create a grid with 2 columns in portrait mode,

it’s the opposite. The confirmation button is

placed at the end of the row (right side).This can be easily handled in Flutter using the

TextDirection property on Row:

<code_start>TextDirection btnDirection =

DeviceType.isWindows ? TextDirection.rtl : TextDirection.ltr;

return Row(

children: [

const Spacer(),

Row(

textDirection: btnDirection,

children: [

DialogButton(

label: 'Cancel',

onPressed: () => Navigator.pop(context, false),

),

DialogButton(

label: 'Ok',

onPressed: () => Navigator.pop(context, true),

),

],

),

],

);<code_end>

<topic_end>

<topic_start>Menu bar

Another common pattern on desktop apps is the menu bar.

On Windows and Linux, this menu lives as part of the Chrome title bar,

whereas on macOS, it’s located along the top of the primary screen.Currently, you can specify custom menu bar entries using

a prototype plugin, but it’s expected that this functionality will

eventually be integrated into the main SDK.It’s worth mentioning that on Windows and Linux,

you can’t combine a custom title bar with a menu bar.

When you create a custom title bar,

you’re replacing the native one completely,

which means you also lose the integrated native menu bar.If you need both a custom title bar and a menu bar,

you can achieve that by implementing it in Flutter,

similar to a custom context menu.<topic_end>

<topic_start>Drag and drop

One of the core interactions for both touch-based and

pointer-based inputs is drag and drop. Although this

interaction is expected for both types of input,

there are important differences to think about when

it comes to scrolling lists of draggable items.Generally speaking, touch users expect to see drag handles

to differentiate draggable areas from scrollable ones,

or alternatively, to initiate a drag by using a long

press gesture. This is because scrolling and dragging

are both sharing a single finger for input.Mouse users have more input options. They can use a wheel

or scrollbar to scroll, which generally eliminates the need

for dedicated drag handles. If you look at the macOS

Finder or Windows Explorer, you’ll see that they work

this way: you just select an item and start dragging.In Flutter, you can implement drag and drop in many

ways. Discussing specific implementations is outside

the scope of this article, but some high level options

are:Use the Draggable and DragTarget APIs

directly for a custom look and feel.Hook into onPan gesture events,

and move an object yourself within a parent Stack.Use one of the pre-made list packages on pub.dev.<topic_end>

<topic_start>

Educate yourself on basic usability principles

Of course, this page doesn’t constitute an exhaustive list

of the things you might consider. The more operating systems,

form factors, and input devices you support,

the more difficult it becomes to spec out every permutation in design.Taking time to learn basic usability principles as a

developer empowers you to make better decisions,

reduces back-and-forth iterations with design during production,

and results in improved productivity with better outcomes.Here are some resources to get you started:

<topic_end>

<topic_start>Update the UI based on orientation

In some situations,

you want to update the display of an app when the user

rotates the screen from portrait mode to landscape mode. For example,

the app might show one item after the next in portrait mode,

yet put those same items side-by-side in landscape mode.In Flutter, you can build different layouts depending

on a given Orientation.

In this example, build a list that displays two columns in

portrait mode and three columns in landscape mode using the

following steps:<topic_end>

<topic_start>

1. Build a GridView with two columns

First, create a list of items to work with.

Rather than using a normal list,

create a list that displays items in a grid.

For now, create a grid with two columns.

<code_start>return GridView.count(

// A list with 2 columns

crossAxisCount: 2,

// ...

);<code_end>

To learn more about working with GridViews,

see the Creating a grid list recipe.<topic_end>

<topic_start>

2. Use an OrientationBuilder to change the number of columns

To determine the app’s current Orientation, use the

OrientationBuilder widget.

The OrientationBuilder calculates the current Orientation by

comparing the width and height available to the parent widget,

and rebuilds when the size of the parent changes.Using the Orientation, build a list that displays two columns in portrait

mode, or three columns in landscape mode.

<code_start>body: OrientationBuilder(

builder: (context, orientation) {

return GridView.count(

// Create a grid with 2 columns in portrait mode,