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Merge pull request #483 from mishadynin/imagecache

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Introduced ImageProvider for asynchronously loading images.
This commit is contained in:
Misha Dynin 2015-11-19 13:00:29 -08:00
commit 04dfa0bf87
2 changed files with 35 additions and 18 deletions
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40
packages/flutter/lib/src/services/image_cache.dart
View File

@ -11,24 +11,44 @@ import 'fetch.dart';
import 'image_decoder.dart';
import 'image_resource.dart';
Future<ui.Image> _fetchImage(String url) async {
UrlResponse response = await fetchUrl(url);
if (response.statusCode >= 400) {
print("Failed (${response.statusCode}) to load image $url");
return null;
/// Implements a way to retrieve an image, for example by fetching it from the network.
/// Also used as a key in the image cache.
abstract class ImageProvider {
Future<ui.Image> loadImage();
}
class _UrlFetcher implements ImageProvider {
final String _url;
_UrlFetcher(this._url);
Future<ui.Image> loadImage() async {
UrlResponse response = await fetchUrl(_url);
if (response.statusCode >= 400) {
print("Failed (${response.statusCode}) to load image $_url");
return null;
}
return await decodeImageFromDataPipe(response.body);
}
return await decodeImageFromDataPipe(response.body);
bool operator ==(other) => other is _UrlFetcher && _url == other._url;
int get hashCode => _url.hashCode;
}
class _ImageCache {
_ImageCache._();
final Map<String, ImageResource> _cache = new Map<String, ImageResource>();
final Map<ImageProvider, ImageResource> _cache =
new Map<ImageProvider, ImageResource>();
ImageResource loadProvider(ImageProvider provider) {
return _cache.putIfAbsent(provider, () {
return new ImageResource(provider.loadImage());
});
}
ImageResource load(String url) {
return _cache.putIfAbsent(url, () {
return new ImageResource(_fetchImage(url));
});
return loadProvider(new _UrlFetcher(url));
}
}

13
packages/flutter/lib/src/widgets/basic.dart
View File

@ -2,7 +2,6 @@
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'dart:typed_data';
import 'dart:ui' as ui;
import 'package:flutter/rendering.dart';
@ -10,7 +9,6 @@ import 'package:flutter/services.dart';
import 'framework.dart';
export 'dart:typed_data' show Uint8List;
export 'package:flutter/rendering.dart' show
BackgroundImage,
BlockDirection,
@ -1180,10 +1178,10 @@ class DefaultAssetBundle extends InheritedWidget {
bool updateShouldNotify(DefaultAssetBundle old) => bundle != old.bundle;
}
class RawImage extends StatelessComponent {
RawImage({
class AsyncImage extends StatelessComponent {
AsyncImage({
Key key,
this.bytes,
this.provider,
this.width,
this.height,
this.colorFilter,
@ -1193,7 +1191,7 @@ class RawImage extends StatelessComponent {
this.centerSlice
}) : super(key: key);
final Uint8List bytes;
final ImageProvider provider;
final double width;
final double height;
final ColorFilter colorFilter;
@ -1203,9 +1201,8 @@ class RawImage extends StatelessComponent {
final Rect centerSlice;
Widget build(BuildContext context) {
ImageResource image = new ImageResource(decodeImageFromList(bytes));
return new ImageListener(
image: image,
image: imageCache.loadProvider(provider),
width: width,
height: height,
colorFilter: colorFilter,