text
stringlengths 1
474
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@override
|
final code = 'Center(\n'
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' child: Container(width: 100, height: 100, color: red))';
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@override
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final String explanation =
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'The screen forces the Center to be exactly the same size as the screen, '
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'so the Center fills the screen.'
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'\n\n'
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'The Center tells the Container that it can be any size it wants, but not bigger than the screen.'
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'Now the Container can indeed be 100x100.';
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@override
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Widget build(BuildContext context) {
|
return Center(
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child: Container(width: 100, height: 100, color: red),
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);
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}
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}
|
//////////////////////////////////////////////////
|
class Example4 extends Example {
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const Example4({super.key});
|
@override
|
final code = 'Align(\n'
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' alignment: Alignment.bottomRight,\n'
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' child: Container(width: 100, height: 100, color: red))';
|
@override
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final String explanation =
|
'This is different from the previous example in that it uses Align instead of Center.'
|
'\n\n'
|
'Align also tells the Container that it can be any size it wants, but if there is empty space it won\'t center the Container. '
|
'Instead, it aligns the Container to the bottom-right of the available space.';
|
@override
|
Widget build(BuildContext context) {
|
return Align(
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alignment: Alignment.bottomRight,
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child: Container(width: 100, height: 100, color: red),
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);
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}
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}
|
//////////////////////////////////////////////////
|
class Example5 extends Example {
|
const Example5({super.key});
|
@override
|
final code = 'Center(\n'
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' child: Container(\n'
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' color: red,\n'
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' width: double.infinity,\n'
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' height: double.infinity))';
|
@override
|
final String explanation =
|
'The screen forces the Center to be exactly the same size as the screen, '
|
'so the Center fills the screen.'
|
'\n\n'
|
'The Center tells the Container that it can be any size it wants, but not bigger than the screen.'
|
'The Container wants to be of infinite size, but since it can\'t be bigger than the screen, it just fills the screen.';
|
@override
|
Widget build(BuildContext context) {
|
return Center(
|
child: Container(
|
width: double.infinity, height: double.infinity, color: red),
|
);
|
}
|
}
|
//////////////////////////////////////////////////
|
class Example6 extends Example {
|
const Example6({super.key});
|
@override
|
final code = 'Center(child: Container(color: red))';
|
@override
|
final String explanation =
|
'The screen forces the Center to be exactly the same size as the screen, '
|
'so the Center fills the screen.'
|
'\n\n'
|
'The Center tells the Container that it can be any size it wants, but not bigger than the screen.'
|
'\n\n'
|
'Since the Container has no child and no fixed size, it decides it wants to be as big as possible, so it fills the whole screen.'
|
'\n\n'
|
'But why does the Container decide that? '
|
'Simply because that\'s a design decision by those who created the Container widget. '
|
'It could have been created differently, and you have to read the Container documentation to understand how it behaves, depending on the circumstances. ';
|
@override
|
Widget build(BuildContext context) {
|
return Center(
|
child: Container(color: red),
|
);
|
}
|
}
|
//////////////////////////////////////////////////
|
class Example7 extends Example {
|
const Example7({super.key});
|
@override
|
final code = 'Center(\n'
|
' child: Container(color: red\n'
|
' child: Container(color: green, width: 30, height: 30)))';
|
@override
|
final String explanation =
|
'The screen forces the Center to be exactly the same size as the screen, '
|
'so the Center fills the screen.'
|
'\n\n'
|
'The Center tells the red Container that it can be any size it wants, but not bigger than the screen.'
|
'Since the red Container has no size but has a child, it decides it wants to be the same size as its child.'
|
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