text
stringlengths 1
372
|
|---|
material widgets
|
<topic_end>
|
<topic_start>
|
container
|
many layouts make liberal use of containers to separate
|
widgets using padding, or to add borders or margins.
|
you can change the device’s background by placing the
|
entire layout into a container and changing its background
|
color or image.
|
<topic_end>
|
<topic_start>
|
summary (container)
|
<topic_end>
|
<topic_start>
|
examples (container)
|
this layout consists of a column with two rows, each containing
|
2 images. a container is used to change the background color
|
of the column to a lighter grey.
|
a container is also used to add a rounded border and margins
|
to each image:
|
<code_start>
|
widget _buildDecoratedImage(int imageIndex) => expanded(
|
child: container(
|
decoration: BoxDecoration(
|
border: border.all(width: 10, color: colors.black38),
|
borderRadius: const BorderRadius.all(Radius.circular(8)),
|
),
|
margin: const EdgeInsets.all(4),
|
child: Image.asset('images/pic$imageIndex.jpg'),
|
),
|
);
|
widget _buildImageRow(int imageIndex) => row(
|
children: [
|
_buildDecoratedImage(imageIndex),
|
_buildDecoratedImage(imageIndex + 1),
|
],
|
);
|
<code_end>
|
you can find more container examples in the tutorial.
|
app source: container
|
<topic_end>
|
<topic_start>
|
GridView
|
use GridView to lay widgets out as a two-dimensional
|
list. GridView provides two pre-fabricated lists,
|
or you can build your own custom grid. when a GridView
|
detects that its contents are too long to fit the render box,
|
it automatically scrolls.
|
<topic_end>
|
<topic_start>
|
summary (gridview)
|
info note
|
when displaying a two-dimensional list where it’s important which
|
row and column a cell occupies (for example,
|
it’s the entry in the “calorie” column for the “avocado” row), use
|
table or DataTable.
|
<topic_end>
|
<topic_start>
|
examples (gridview)
|
uses GridView.extent to create a grid with tiles a maximum
|
150 pixels wide.
|
app source: grid_and_list
|
uses GridView.count to create a grid that’s 2 tiles
|
wide in portrait mode, and 3 tiles wide in landscape mode.
|
the titles are created by setting the footer property for
|
each GridTile.
|
dart code:
|
grid_list_demo.dart
|
<code_start>
|
widget _buildGrid() => GridView.extent(
|
maxCrossAxisExtent: 150,
|
padding: const EdgeInsets.all(4),
|
mainAxisSpacing: 4,
|
crossAxisSpacing: 4,
|
children: _buildGridTileList(30));
|
// the images are saved with names pic0.jpg, pic1.jpg...pic29.jpg.
|
// the list.generate() constructor allows an easy way to create
|
// a list when objects have a predictable naming pattern.
|
List<Container> _buildGridTileList(int count) => list.generate(
|
count, (i) => container(child: image.asset('images/pic$i.jpg')));
|
<code_end>
|
<topic_end>
|
<topic_start>
|
ListView
|
ListView, a column-like widget, automatically
|
provides scrolling when its content is too long for
|
its render box.
|
<topic_end>
|
<topic_start>
|
summary (listview)
|
<topic_end>
|
<topic_start>
|
examples (listview)
|
uses ListView to display a list of businesses using
|
ListTiles. a divider separates the theaters from
|
the restaurants.
|
app source: grid_and_list
|
uses ListView to display the colors from
|
the material 2 design palette
|
for a particular color family.
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.