解决了，原来是引用那写错了，应该直接调用函数就行了。

代码照着你视频搞的。
import ‘dart:io’;

import ‘package:flutter/material.dart’;
import ‘package:flutter_color_plugin/flutter_color_plugin.dart’;
import ‘package:image_picker/image_picker.dart’;

class PhotoApp extends StatefulWidget {
// This widget is the root of your application.
@override
State createState() => _PhotoApp();
}

class _PhotoApp extends State {
List _images = [];

Future getImage(bool isTakePhoto) async {
var image = await ImagePicker.pickImage(
source: isTakePhoto ? ImageSource.camera : ImageSource.gallery);
Navigator.pop(context);
setState(() {
_images.add(image);
});
}

TextStyle textStyle = TextStyle(fontSize: 20);

@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(‘Image Picker Example’),
),
body: Center(
child: Wrap(
spacing: 5,
runSpacing: 5,
children: [_genImages()],
)),
floatingActionButton: FloatingActionButton(
onPressed: _PickImage,
tooltip: ‘Pick Image’,
child: Icon(Icons.add_a_photo),
),
);
}

_PickImage() {
showModalBottomSheet(
context: context,
builder: (context) => Container(
height: 120,
child: Column(
children: [
_item(‘拍照’, true),
_item(‘从相册选择’, false),
],
),
));
}

_item(String title, bool isTakePhoto) {
return GestureDetector(
child: ListTile(
leading: Icon(isTakePhoto ? Icons.camera_alt : Icons.photo),
title: Text(title),
onTap: () => getImage(isTakePhoto),
));
}

_genImages() {
return _images.map((file) {
return Stack(
children: [
ClipRRect(
//圆角效果
borderRadius: BorderRadius.circular(5),
child: Image.file(file, width: 120,height: 90,fit: BoxFit.fill,),//BoxFit.fill填充满容器
),
Positioned(
right: 5,
top: 5,
child: GestureDetector(
onTap: (){
setState(() {
_images.remove(file);
});
},
child: ClipOval(
//圆角删除按钮
child: Container(
padding: EdgeInsets.all(3),
decoration: BoxDecoration(color: Colors.black54),
child: Icon(Icons.close, size: 18,color: Colors.white,),
),
),
),
)
],
);
}).toList();
}
}