flutter - 使用ImagePicker从图库中保存Flutter图像

Question

我具有此功能来保存图库中的图像并将其显示为背景:

Future _getImage() async {
// ImagePicker picker = ImagePicker();

PickedFile pickedFile = await picker.getImage(source: ImageSource.gallery);

if (pickedFile == null) return;
File tmpFile = File(pickedFile.path);
tmpFile = await tmpFile.copy(tmpFile.path);

setState(() {
  if (pickedFile != null) {
    //_image = File(pickedFile.path);
    _image = tmpFile;
    print('_image: $_image');
  } else {
    print('No image selected');
  }
});

}
但是在我调用它之后，它说图像为空:
文件:“/ data / user / 0 / com.app.flutter / cache / image_picker5156338879856055755740.jpg”为空，无法加载为图像。
我不确定这里发生了什么，因为它可以在控制台中很好地打印图像，如下所示:
_image:文件:'/ data / user / 0 / com.app.flutter / cache / image_picker51563388798560557557.jpg
所以它意味着它在缓存中，但是由于某种原因，它返回为空并且不会将图像添加到后台:

 decoration: BoxDecoration(
      image: DecorationImage(
        image: _image == null
            ? MemoryImage(kTransparentImage)
            : FileImage(_image),
        fit: BoxFit.cover,

添加构建以防万一那里有一个错误，但我认为不存在。基本上，我只需要画廊中的图像即可持久并保留在应用程序中。
编辑:将setState()添加到代码中，但是它仍然不是持久性的，肯定有我缺少的东西:

Future _getImage() async {
// ImagePicker picker = ImagePicker();

PickedFile pickedFile = await picker.getImage(source: ImageSource.gallery);

if (pickedFile == null) {
  return null;
}

Directory appDirectory = await getApplicationDocumentsDirectory();
File newImage = File(appDirectory.path + 'fileName');
newImage.writeAsBytes(File(pickedFile.path).readAsBytesSync());

setState(() {
  _image = newImage;
  print(newImage.path + ' test');
});

}

Answer 1

试试这个

Future _getImage() async {
  ImagePicker picker = ImagePicker();
  final pickedFile = await picker.getImage(source: ImageSource.gallery);
  if (pickedFile == null) {
    return null;
  }
  Directory appDirectory = await getApplicationDocumentsDirectory();
  File newImage = File(appDirectory.path + 'fileName');
  await newImage.writeAsBytes(File(pickedFile.path).readAsBytesSync());

  setState(() {
    _image = newImage;
  });
}