无法打开文件，路径=“文件：///路径”（OS错误：没有这样的文件或目录，错误号= 2）

Question

你好我试图缩小图像尺寸使用图像库 从画廊挑选，而试图，我这样

E/flutter (13796): [ERROR:lib/tonic/logging/dart_error.cc(16)] Unhandled exception: 
E/flutter (13796): FileSystemException: Cannot open file, path = 'file:///storage/emulated/0/WhatsApp/Media/WhatsApp%20Images/IMG-20171016-WA0020.jpg' (OS Error: No such file or directory, errno = 2) 
E/flutter (13796): #0  _File.throwIfError (file_impl.dart:618) 
E/flutter (13796): #1  _File.openSync (file_impl.dart:473) 
E/flutter (13796): #2  _File.readAsBytesSync (file_impl.dart:533) 
E/flutter (13796): #3  _AddNewUserState.qqq (/data/data/com.prayuta.chitfunds/cache/chitfundsUNFPRG/chitfunds/lib/users.dart:420:97) 
E/flutter (13796): <asynchronous suspension> 
E/flutter (13796): #4  _AddNewUserState.build.<anonymous closure> (/data/data/com.prayuta.chitfunds/cache/chitfundsUNFPRG/chitfunds/lib/users.dart:686:19) 
E/flutter (13796): #5  GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:102:24) 
E/flutter (13796): #6  TapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:149:9) 
E/flutter (13796): #7  TapGestureRecognizer.acceptGesture (package:flutter/src/gestures/tap.dart:119:7) 
E/flutter (13796): #8  GestureArenaManager.sweep (package:flutter/src/gestures/arena.dart:156:27) 
E/flutter (13796): #9   BindingBase&SchedulerBinding&GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:147:20) 
E/flutter (13796): #10  BindingBase&SchedulerBinding&GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:121:22) 
E/flutter (13796): #11  BindingBase&SchedulerBinding&GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:101:7) 
E/flutter (13796): #12  BindingBase&SchedulerBinding&GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:64:7) 
E/flutter (13796): #13  BindingBase&SchedulerBinding&GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:48:7) 
E/flutter (13796): #14  _invoke1 (file:///b/build/slave/Linux_Engine/build/src/flutter/lib/ui/hooks.dart:100) 
    E/flutter (13796): #15  _dispatchPointerDataPacket (file:///b/build/slave/Linux_Engine/build/src/flutter/lib/ui/hooks.dart:58) 

面临的错误任何一个可以帮助我的代码看起来像这样

import 'package:image/image.dart' as convertinglib; 
File imageFile = await ImagePicker.pickImage(); 
convertinglib.Image image = convertinglib.decodeImage(new Io.File(imageFile.uri.toString()).readAsBytesSync()); 
convertinglib.Image thumbnail = convertinglib.copyResize(image, 120); 

Answer 1

的问题不是在读取文件图片选择器或转换为更小的尺寸，但与将文件写入文件系统。我拿它，你拿了dart image package 的示例代码，它在调整文件大小后将文件写入文件系统。这种形式在智能手机上不可能实现。

您发布实际上并没有造成错误，但该行做的代码：

new Io.File(imageFile.uri.toString()) 
    ..writeAsBytesSync(convertingLib.encodePng(thumbnail)) 

这样做的问题是，imagePicker隐藏图像的实际URI。它为您提供了一条如下所示的路径：.../tmp/image_picker_1547A964-791E-426F-A682-33D3AFA995BA-18295-0003861F9255294A.jpg不能用于保存您的新缩略图。

您可以尝试避免将文件保存在第一位或将其保存到实际存在的位置（例如，您可以使用path_provider plugin作为此目的）。

Answer 2

我想这个问题是通过图像URI作为一个字符串。 有一个fromUri构造函数，您可以在其中传递文件URI。

使用try

new Io.File.fromUri(imageFile.uri) 

代替

new Io.File(imageFile.uri.toString())