Flutter：如何使用Image插件调整图像大小

Question

Flutter：如何使用Image插件调整图像大小

4

我正在尝试使用Flutter插件“Image”https://pub.dartlang.org/packages/image来调整图像大小。

按照说明书上的方法，我正在使用以下方法：

  File resizeMyImage(File resizeThisFile) {
    // decodeImage will identify the format of the image and use the appropriate
    // decoder.
    File myCompressedFile;
    Image image = decodeImage(resizeThisFile.readAsBytesSync());

    // Resize the image to a 120x? thumbnail (maintaining the aspect ratio).
    Image thumbnail = copyResize(image, 120);

    // Save the thumbnail as a PNG.
    myCompressedFile = new Io.File('thumbnail.png')..writeAsBytesSync(encodePng(thumbnail));

   return myCompressedFile;
  }

我收到的错误信息

E/flutter (22897): FileSystemException: Cannot open file, path = 'thumbnail.png' (OS Error: Read-only file system, errno = 30)

任何帮助都将不胜感激 - 谢谢。

工作中的调整大小类如下所示。希望能对某些人有所帮助。

import 'dart:async';
import 'dart:io' as Io;
import 'dart:io';
import 'package:image/image.dart';
import 'package:path_provider/path_provider.dart';

class ResizeImage {

  String tempPath;

  Future main() async {
  }


  Future<Io.File> resizeMyImage(File resizeThisFile) async {
    Directory tempDir = await getTemporaryDirectory();
    tempPath = tempDir.path;

    // decodeImage will identify the format of the image and use the appropriate
    // decoder.
    File myCompressedFile;
    Image image = decodeImage(resizeThisFile.readAsBytesSync());

    // Resize the image to a 120x? thumbnail (maintaining the aspect ratio).
    Image thumbnail = copyResize(image, 120);

    // Save the thumbnail as a PNG.
    print('resizeMyImage............tempPath: '+tempPath);
    myCompressedFile = new Io.File(tempPath+'thumbnail.png')..writeAsBytesSync(encodePng(thumbnail));

   return myCompressedFile;
  }
}

- AhabLives

1个回答

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- Günter Zöchbauer · Answer 1

无法在当前目录中创建文件，因为正如错误消息所述，它是只读的。

https://pub.dartlang.org/packages/path_provider 允许您获取有效目录的路径

Directory tempDir = await getTemporaryDirectory();
String tempPath = tempDir.path;

Directory appDocDir = await getApplicationDocumentsDirectory();
String appDocPath = appDocDir.path;