class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});
  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;
  List pickerChildren = ["1", "2", "3","4","5","6","7","8","9","10"];
  var controllr=FixedExtentScrollController(initialItem:0);


  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
              Container(
                height: 200,
                child:CupertinoPicker(
                  //子项高度，选中位置的高度
                  itemExtent: 30,
                  scrollController: controllr,
                  //直径比
                  diameterRatio: 1.1,
                  //轴偏移，默认是0.0。控制选中的子widget的左右偏移   正数 >   负数 <  0不偏移
                  offAxisFraction:0,
                  //放大效果 默认false  false关闭  true开启
                  useMagnifier:true,
                  //放大倍数，需先开启放大效果，此参数才有作用。
                  magnification:1.3,
                  //压缩，这个控制的children之间的空隙，和diameterRatio的效果有相似之处。
                  squeeze:1.6,
                  backgroundColor:Colors.white,
                  //滚动选择的回调，每次滚动，都会触发此回调，会将选中的子widget的position返回。
                  onSelectedItemChanged: (int value) {
                    _counter=value;
                    print('The position is $value');
                    //controllr.selectedItem 相当于onSelectedItemChanged中position
                    //当前选择的第几个item
                    print(controllr.selectedItem);
                  },
                  children: pickerChildren.map((e){
                    return Text("${e}天",style:TextStyle(color:Colors.black));
                  }).toList(),
                ),
              ),
            ],
        ),
      ),
    );
  }
}