Im new to null safety how can u solve this ? I made the custom painter but its giving me error

Flutter Discussion
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#1

class SetDrawingArea{
Offset points;
Paint paintArea ;

SetDrawingArea({
this.points,
this.paintArea,
});
}

class MyCustomPainter extends CustomPainter
{
List allPoints ;

MyCustomPainter({required List allPoints }) : this.allPoints = allPoints.toList();

@override
void paint(Canvas canvas, Size size) {
// TODO: implement paint
Paint background = Paint()…color = Colors.black;
Rect rect = Rect.fromLTWH(0, 0, size.width, size.height);
canvas.drawRect(rect,background);
canvas.clipRect(rect);

for(int i=0;i<allPoints.length-1;i++){
  if(allPoints[i] != null && allPoints[i+1] != null){
    canvas.drawLine(allPoints[i].points,allPoints[i+1].points,allPoints[i].paintArea);
  }else if(allPoints[i] != null && allPoints[i+1] == null){
    canvas.drawPoints(PointMode.points,[allPoints[i].points],allPoints[i].paintArea);
  }
}

}

@override
bool shouldRepaint(MyCustomPainter oldDelegate) {
// TODO: implement shouldRepaint
return oldDelegate.allPoints != allPoints;
}

}