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@rodydavis
Last active June 19, 2022 11:15
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import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Draggable Custom Painter',
home: Scaffold(
body: DraggableCustomPainter(),
),
);
}
}
class DraggableCustomPainter extends StatefulWidget {
@override
_DraggableCustomPainterState createState() => _DraggableCustomPainterState();
}
class _DraggableCustomPainterState extends State<DraggableCustomPainter> {
var xPos = 0.0;
var yPos = 0.0;
final width = 100.0;
final height = 100.0;
bool _dragging = false;
final _paint = Paint();
/// Is the point (x, y) inside the rect?
bool _insideRect(double x, double y) =>
x >= xPos && x <= xPos + width && y >= yPos && y <= yPos + height;
@override
Widget build(BuildContext context) {
return GestureDetector(
onPanStart: (details) => _dragging = _insideRect(
details.globalPosition.dx,
details.globalPosition.dy,
),
onPanEnd: (details) {
_dragging = false;
},
onPanUpdate: (details) {
if (_dragging) {
setState(() {
xPos += details.delta.dx;
yPos += details.delta.dy;
});
}
},
child: Container(
child: CustomPaint(
painter: RectanglePainter(
rect: Rect.fromLTWH(xPos, yPos, width, height),
painter: _paint,
),
child: Container(),
),
),
);
}
}
class RectanglePainter extends CustomPainter {
RectanglePainter({
@required this.rect,
@required this.painter,
});
final Rect rect;
final Paint painter;
@override
void paint(Canvas canvas, Size size) {
canvas.drawRect(rect, painter);
}
@override
bool shouldRepaint(CustomPainter oldDelegate) => true;
}
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