network_to_file_image 2.0.7 network_to_file_image: ^2.0.7 copied to clipboard
Opens a local image file, if it exists there. If it doesn't, fetches the image from the network and then saves to the local file for next time.
network_to_file_image #
This is a mixture of FileImage
and NetworkImage
.
It will download the image from the url once, save it locally in the file system,
and then use it from there in the future.
In more detail:
Given a file and url of an image, it first tries to read it from the local file.
It decodes the given File
object as an image, associating it with the given scale.
However, if the image doesn't yet exist as a local file, it fetches the given URL from the network, associating it with the given scale, and then saves it to the local file. The image will be cached regardless of cache headers from the server.
Notes:
-
If the provided url is null or empty,
NetworkToFileImage
will default toFileImage
. It will read the image from the local file, and won't try to download it from the network. -
If the provided file is null,
NetworkToFileImage
will default toNetworkImage
. It will download the image from the network, and won't save it locally.
Usage #
Import the package #
First, add network_to_file_image as a dependency in your pubspec.yaml
Then, import it:
import 'package:network_to_file_image/network_to_file_image.dart';
Use the package #
If you also listed path_provider
in your pubspec.yaml file:
path_provider: ^0.4.1
Then you can create a file from a file name:
Future<File> file(String filename) async {
Directory dir = await getApplicationDocumentsDirectory();
String pathName = p.join(dir.path, filename);
return File(pathName);
}
var myFile = await file("myFileName.png"),
Then, create the image:
Image(image: NetworkToFileImage(url: "http://example.com/someFile.png", file: myFile))
If you make debug: true
it prints to the console whether the image was read from
the file or fetched from the network:
Image(image: NetworkToFileImage(url: "http://example.com/someFile.png", file: myFile, debug: true))
Don't forget to check the example tab.
Tests #
You can set mock files. Please see methods:
setMockFile(File file, Uint8List bytes)
setMockUrl(String url, Uint8List bytes)
clearMocks()
clearMockFiles()
clearMockUrls()
See also #
The Flutter packages I've authored:
- async_redux
- align_positioned
- network_to_file_image
- matrix4_transform
- back_button_interceptor
- indexed_list_view
- animated_size_and_fade
---
Marcelo Glasberg:
https://github.com/marcglasberg
https://twitter.com/glasbergmarcelo
https://stackoverflow.com/users/3411681/marcg
https://medium.com/@marcglasberg