如何在 Flutter 中获取 Asset 对象的路径？

Posted 2023-02-16

【中文标题】如何在 Flutter 中获取 Asset 对象的路径？

【英文标题】：How to get path of an Asset object in Flutter?

【发布时间】：2020-06-19 17:13:20

【问题描述】：

我在颤振中使用多图像选择器，我必须将这些图像加载到文件中才能在照片视图中显示它们..

我确定我将资产转换为文件的方法不合适。 我无法做到这一点，因为我总是收到文件未找到异常。

这是我的代码：

import 'package:multi_image_picker/multi_image_picker.dart';
import 'package:flutter/material.dart';
import 'dart:async';
import 'dart:io';
import 'package:flutter_swiper/flutter_swiper.dart';
import 'package:photo_view/photo_view.dart';
import 'package:flutter_absolute_path/flutter_absolute_path.dart';
import 'package:path_provider/path_provider.dart';
import 'package:path_provider_platform_interface/path_provider_platform_interface.dart';
void main() => runApp(AddPost());
class AddPost extends StatefulWidget 
@override
_MyAppState createState() => new _MyAppState();


class _MyAppState extends State<AddPost> 
List<Asset> images = List<Asset>();
//File images;
List<File>files=List<File>();
String _error = 'No Error Dectected';
var width;
var height;
@override
void initState() 
super.initState();
 
void getFileList() async 
for (int i = 0; i < images.length; i++) 
  String filename=images[i].name;
String dir = (await getApplicationDocumentsDirectory()).path;
String path='$dir/$filename';
  var path2 = await FlutterAbsolutePath.getAbsolutePath(path);
  //var path = await images[i].filePath; ( the file path thing is not found)
  print(path2);
  var file = await getImageFileFromAsset(path2);
  print(file);
  files.add(file);
  
  

  Future<File> getImageFileFromAsset(String path) async 
  final file = File(path);
  return file;
     




  Widget buildGridView() 

return new Swiper(
    loop: false,

    itemCount: files==null?0:files.length,
    pagination: new SwiperPagination(
      // margin: new EdgeInsets.all(5.0),
        builder: new DotSwiperPaginationBuilder(
            color: Colors.purple, activeColor: Colors.green)),
    itemBuilder: (BuildContext context, int index) 
      return Container(

          child: PhotoView(
            gaplessPlayback: false,
            backgroundDecoration: BoxDecoration(color: Colors.transparent),
            minScale: PhotoViewComputedScale.contained ,
            maxScale: PhotoViewComputedScale.covered ,
            imageProvider: ,

          ));
    
);
 

Future<void> loadAssets() async 
List <Asset>resultList ;
try 

  resultList = await  MultiImagePicker.pickImages(
      maxImages: 6,
      enableCamera: true,
      selectedAssets: images,
      cupertinoOptions: CupertinoOptions(takePhotoIcon: "chat"),
      materialOptions: MaterialOptions(
        actionBarColor: "#abcdef",
        actionBarTitle: "Example App",
        allViewTitle: "All Photos",
        useDetailsView: false,
        selectCircleStrokeColor: "#000000",
      ));

 on Exception catch (e) 
  error = e.toString();


// If the widget was removed from the tree while the asynchronous platform
// message was in flight, we want to discard the reply rather than calling
// setState to update our non-existent appearance.
if (!mounted) return;

setState(() 
  images = resultList;
  _error = error;
  getFileList();
);




 

 @override
 Widget build(BuildContext context) 

return new MaterialApp(
  home: new Scaffold(
    appBar: new AppBar(
      title: const Text('Plugin example app'),
    ),
    body: Column(
      children: <Widget>[
        Center(child: Text('Error: $_error')),
        RaisedButton(
          child: Text("Pick images"),
          onPressed: loadAssets,
        ),
        Expanded(
          child: buildGridView(),
        ),

      ],
    ),
  ),
);
 
 

这些是我得到的错误：

java.io.FileNotFoundException：没有内容提供者：/data/user/0/xperience.flutter_app/app_flutter/Camera

除了：

未处理的异常：MissingPluginException（在通道 flutter_absolute_path 上找不到方法 getAbsolutePath 的实现）

感谢任何帮助。

【参考方案1】：

我通过放置 images[i].identifier 解决了我的问题

 void getFileList() async 
 files.clear();
 for (int i = 0; i < images.length; i++) 
  var path2 = await FlutterAbsolutePath.getAbsolutePath(images[i].identifier);
  //var path = await images[i].filePath;
  print(path2);
  var file = await getImageFileFromAsset(path2);
  print(file);
  files.add(file);

【讨论】：

你好，是返回原图的路径还是复制到应用缓存目录的图片？