【发布时间】：2019-07-30 06:35:47
【问题描述】：
有没有办法在颤振中创建流程图或主干？ 也许您对我如何构建它有想法或示例。我目前的尝试是将元素拖放到地方，这也有效。但是现在我遇到了无法将元素相互连接的问题。我已经尝试过失败的CustomPainter baer
class _main extends State<Main> {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Stammbaum'),
backgroundColor: Colors.pink),
body: Column(
children: <Widget>[
Container(
decoration: BoxDecoration(
border:Border.all(color: Colors.black, width: 0.3)
),
child: Row(
children: <Widget>[
Padding(
padding: EdgeInsets.all(10),
child:Draggable(
data: 1,
child: Icon(Icons.access_alarm),
feedback: Icon(Icons.access_alarm),
childWhenDragging: Icon(Icons.access_alarm),
),
),
Padding(
padding: EdgeInsets.all(10),
child: Draggable(
data: 2,
child: Icon(Icons.accessibility_new),
feedback: Icon(Icons.accessibility_new),
childWhenDragging: Icon(Icons.accessibility_new),
),
),
Padding(
padding: EdgeInsets.all(10),
child: Draggable(
data: 3,
child: Icon(Icons.delete),
feedback: Icon(Icons.delete),
childWhenDragging: Icon(Icons.delete),
),
),
],
),
),
Column(
children: <Widget>[
ContentRow(),
ContentRow(),
ContentRow(),
ContentRow(),
ContentRow(),
ContentRow(),
ContentRow(),
ContentRow(),
ContentRow(),
],
)
],
),
);
}
}
class ContentRow extends StatelessWidget{
@override
Widget build(BuildContext context) {
return Row(
children: <Widget>[
Content(),
Content(),
Content(),
Content(),
Content(),
Content(),
Content(),
],
);
}
}
var p1;
var p2;
class Content extends StatelessWidget{
bool firstTap = true;
var p1;
var p2;
@override
Widget build(BuildContext context) {
bool accepted = false;
Icon dataIcon ;
_onTapDown(TapDownDetails details) {
var x = details.globalPosition.dx;
var y = details.globalPosition.dy;
if(firstTap ){
p1 = Offset(x, y);
firstTap = false;
}else{
p2 = Offset(x, y);
firstTap=true;
print("$p1 , $p2");
}
}
return GestureDetector(
onTapDown: (TapDownDetails details) => _onTapDown(details),
child:Container(
width: 50.0,
height: 50.0,
child: DragTarget(
builder: (context, List<int> candidateData, rejectedData) {
print(candidateData);
return accepted ? dataIcon : Container();
},
onWillAccept: (data) {
return true;
},
onAccept: (data) {
if(data==1){
accepted=true;
dataIcon = Icon(Icons.access_alarm);
}
if (data==2){
accepted=true;
dataIcon=Icon(Icons.accessibility_new);
}
if(data==3){
accepted=false;
dataIcon=null;
}
},
),
) ,
) ;
}
}
class MyPainter extends CustomPainter { // <-- CustomPainter class
@override
void paint(Canvas canvas, Size size) {
final point1 = p1;
final point2 =p2;
final paint = Paint()
..color = Colors.black
..strokeWidth = 2;
canvas.drawLine(point1, point2, paint);
}
@override
bool shouldRepaint(CustomPainter old) {
return false;
}
}
【问题讨论】：
-
请发布您渲染的小部件的屏幕截图。