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}
<code_end>
if you have many items you want to wrap in a scroll,
even of different widget types, you might want to use a ListView.
this might seem like overkill, but in flutter this is
far more optimized and less intensive than a Xamarin.Forms ListView,
which is backing on to platform specific controls.
<code_start>
@override
widget build(BuildContext context) {
return ListView(
children: const <widget>[
Text('Row one'),
Text('Row two'),
Text('Row three'),
Text('Row four'),
],
);
}
<code_end>
<topic_end>
<topic_start>
how do i handle landscape transitions in flutter?
landscape transitions can be handled automatically by setting the
configChanges property in the AndroidManifest.xml:
<topic_end>
<topic_start>
gesture detection and touch event handling
<topic_end>
<topic_start>
how do i add GestureRecognizers to a widget in flutter?
in Xamarin.Forms, elements might contain a click event you can attach to.
many elements also contain a command that is tied to this event.
alternatively you would use the TapGestureRecognizer.
in flutter there are two very similar ways:
if the widget supports event detection, pass a function to it and
handle it in the function. for example, the ElevatedButton has an
onPressed parameter:
<code_start>
@override
widget build(BuildContext context) {
return ElevatedButton(
onPressed: () {
developer.log('click');
},
child: const Text('Button'),
);
}
<code_end>
if the widget doesn’t support event detection, wrap the
widget in a GestureDetector and pass a function
to the onTap parameter.
<code_start>
class SampleApp extends StatelessWidget {
const SampleApp({super.key});
@override
widget build(BuildContext context) {
return scaffold(
body: center(
child: GestureDetector(
onTap: () {
developer.log('tap');
},
child: const FlutterLogo(size: 200),
),
),
);
}
}
<code_end>
<topic_end>
<topic_start>
how do i handle other gestures on widgets?
in Xamarin.Forms you would add a GestureRecognizer to the view.
you would normally be limited to TapGestureRecognizer,
PinchGestureRecognizer, PanGestureRecognizer, SwipeGestureRecognizer,
DragGestureRecognizer and DropGestureRecognizer unless you built your own.
in flutter, using the GestureDetector,
you can listen to a wide range of gestures such as:
the following example shows a GestureDetector
that rotates the flutter logo on a double tap:
<code_start>
class RotatingFlutterDetector extends StatefulWidget {
const RotatingFlutterDetector({super.key});
@override
State<RotatingFlutterDetector> createState() =>
_RotatingFlutterDetectorState();
}
class _RotatingFlutterDetectorState extends State<RotatingFlutterDetector>
with SingleTickerProviderStateMixin {
late final AnimationController controller;
late final CurvedAnimation curve;
@override
void initState() {
super.initState();
controller = AnimationController(
duration: const duration(milliseconds: 2000),
vsync: this,
);
curve = CurvedAnimation(parent: controller, curve: Curves.easeIn);