disposable_cached_images 0.0.5

Flutter package for displaying images from the Internet and keeping them in the cache directory.

A flutter package for displaying and releasing images from memory.

Features

Download and display images from the Internet and keep them in the cache directory.

Display images assets.

Cancel the download if the image widget has been disposed to reduce bandwidth usage.

Remove the image from memory if the image widget has been disposed to reduce device memory usage.

Usage

Setting up

Add scaffoldMessengerKey to the MaterialApp

you can read more about scaffoldMessengerKey on docs.flutter

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: const Home(),
      scaffoldMessengerKey: scaffoldMessengerKey,
    );
  }
}

final scaffoldMessengerKey = GlobalKey<ScaffoldMessengerState>();

In the main method use runAppWithDisposableCachedImage instead of runApp and pass it the scaffoldMessengerKey to initialize the package

the scaffoldMessengerKey.currentContext is used to precache the image ahead of being request in the ui, learn more about precacheImage.

void main() {
  runAppWithDisposableCachedImage(
    const MyApp(),
    scaffoldMessengerKey: scaffoldMessengerKey,
  );
}

If you are already using flutter_riverpod, you can pass ProviderScope arguments observers and overrides to the runAppWithDisposableCachedImage function.

Now your app is ready to use the package.

Displaying images

Use DisposableCachedImageWidget to display images form internet.

DisposableCachedImageWidget(
image: 'https://picsum.photos/id/23/200/300',
);

You can also display images form assets by passing the image path.

DisposableCachedImageWidget(
image: 'images/a_dot_burr.jpeg',
);

The image url must start with http and if it doesn't start with http the package will assume the image is an asset.

You can display your custom widgets while the image is loading, has an error and when it is ready as shown below

DisposableCachedImageWidget(
 image: imageUrl,
 onLoading: (context) => const Center(
   child: Icon(Icons.downloading),
 ),
 onError: (context, reDownload) => Center(
   child: IconButton(
     onPressed: reDownload,
     icon: const Icon(Icons.download),
   ),
 ),
 onImage: (context, memoryImage) => Container(
   decoration: BoxDecoration(
     borderRadius: BorderRadius.circular(20),
     image: DecorationImage(
       image: memoryImage,
       fit: BoxFit.cover,
     ),
   ),
 ),
);

You can Provide a maximum height and width values for image by passing the values to maxCacheHeight and maxCacheWidth arguments, If the actual height or width of the image is less than the provided value, the provided value will be ignored.

The image will be resized before it's displayed in the UI and saved to the device storage.

DisposableCachedImageWidget(
 image: imageUrl,
 maxCacheHeight: 300,
 maxCacheWidth: 300,
);

How it works

Stores and retrieves files using dart:io.

Disposing and changing image state using flutter_riverpod with state_notifier.

Using http to download images from the internet.

Example app

The example directory has a sample application that uses this plugin.

Roadmap

Improve package documentation

Web support

Further improvements