我正在使用Flutter构建照片编辑应用程序，可以将内置的照片滤镜应用于从图库中选取的图像

编程问答 2022-06-05

问题描述

我已经从每个插件的官方文档中获取帮助来编写代码。尽管如此，我还是收到下面提到的错误。谁能帮忙解决什么问题？

import 'dart:html';

import 'package:Flutter/material.dart';
import 'package:Flutter/semantics.dart';
import 'package:path/path.dart';
import 'package:photofilters/photofilters.dart';
import 'package:image_picker/image_picker.dart';
import 'package:image/image.dart' as imageLib;

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  File _image;
  String fileName;
  Filter _filter;
  List<Filter> filters = presetFiltersList;
  final picker = ImagePicker();
  Future getimage() async {
    final pickedFile = await picker.getimage(source: ImageSource.gallery);
    fileName = basename(pickedFile.path);
    var image = imageLib.decodeImage(pickedFile.readAsBytesSync());
    setState(() {
      if (pickedFile != null) {
        _image = File(pickedFile.path);
      } else {
        print('No image selected.');
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      floatingActionButton: FloatingActionButton.extended(
        onpressed: () {
          getimage();
          Navigator.push(
              context,MaterialPageRoute(
                builder: (context) => PhotoFilterSelector(
                  image: _image,filters: filters,filename: fileName,loader: Center(child: CircularProgressIndicator()),),));
        },label: Text("+"),icon: Icon(
          Icons.print,color: Colors.black,);
  }
}

错误：

  1. 未为类型“ PickedFile”定义方法“ readAsBytesSync”。 尝试将名称更正为现有方法的名称，或定义一个名为“ readAsBytesSync”的方法。

  2. 2个位置参数，但找到1个。 尝试添加缺少的参数。

3。无法将参数类型“字符串”分配给参数类型“列表”。

  1. 不能将参数类型“文件”分配给参数类型“图像”。

解决方法

您可以在下面复制粘贴运行完整代码
步骤1：使用imageLib.Image _image;而不是File _image;
步骤2：使用_file.readAsBytesSync() 

 File _file = File(pickedFile.path);
_image = imageLib.decodeImage(_file.readAsBytesSync());

第3步：onPressed需要使用async和await 

onPressed: () async{
          await getImage();

工作演示

enter image description here

完整代码

import 'package:flutter/material.dart';
import 'dart:io';
import 'package:flutter/semantics.dart';
import 'package:path/path.dart';
import 'package:photofilters/photofilters.dart';
import 'package:image_picker/image_picker.dart';
import 'package:image/image.dart' as imageLib;

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  imageLib.Image _image;
  //File _image;
  String fileName;
  Filter _filter;
  List<Filter> filters = presetFiltersList;
  final picker = ImagePicker();
  Future getImage() async {
    PickedFile pickedFile = await picker.getImage(source: ImageSource.gallery);
    fileName = basename(pickedFile.path);
    File _file = File(pickedFile.path);
    _image = imageLib.decodeImage(_file.readAsBytesSync());
    setState(() {
      if (pickedFile != null) {
        //_image = File(pickedFile.path);
      } else {
        print('No image selected.');
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      floatingActionButton: FloatingActionButton.extended(
        onPressed: () async{
          await getImage();
          Navigator.push(
              context,MaterialPageRoute(
                builder: (context) => PhotoFilterSelector(
                  title: Text("Photo Filter Example"),image: _image,filters: filters,filename: fileName,loader: Center(child: CircularProgressIndicator()),),));
        },label: Text("+"),icon: Icon(
          Icons.print,color: Colors.black,);
  }
}

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',theme: ThemeData(
        primarySwatch: Colors.blue,visualDensity: VisualDensity.adaptivePlatformDensity,home: MyHomePage(),);
  }
}
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