[英]Flutter: how to create moveable widget
我試圖創建一個可移動的文本小部件。
當我按下小部件並開始在屏幕上移動手指(仍然按下小部件)時,小部件的 position 也應該移動。
我試圖用 GestureDetector 和 Transform 小部件來做到這一點。
這是代碼:
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
debugShowCheckedModeBanner: false,
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
final String title;
MyHomePage({Key? key, required this.title}) : super(key: key);
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
MoveText(),
],
),
),
);
}
}
class MoveText extends StatefulWidget{
@override
_MoveTextState createState() => _MoveTextState();
}
class _MoveTextState extends State<MoveText> {
Offset offset = Offset(0.0, 0.0);
@override
Widget build(BuildContext context) {
return GestureDetector(
onLongPressMoveUpdate: (LongPressMoveUpdateDetails details) {
print('${details.localPosition}');
},
onPanStart: (details){
},
onPanUpdate: (details){
print('Pan update ${details.localPosition}');
setState((){
offset = details.localPosition;
});
},
onPanCancel: (){
print('Pan cancel');
},
child: Transform(
transform: Matrix4.translationValues(offset.dx, offset.dy, 0.0),
child: Container(
height: 50,
width: 200,
color: Colors.yellow,
child: Text('Some text for test'),
),
),
);
}
}
當我第一次點擊小部件並開始移動時,一切正常,但是當我停止並想再次開始移動時,不會調用 onPanUpdate。
有沒有人有解決這個問題的方法?
您需要的是一個Draggable
小部件。
訪問以獲取更多信息: https://api.flutter.dev/flutter/widgets/Draggable-class.html
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