Summary:
Change `RCTImageDownloader` so it stores the `RCTDownloadTaskWrapper` for reuse. Modify `RCTDownloadTaskWrapper` to use associated objects to store the completion/progress blocks.
Summary:
This PR adds 4 native events to NetworkImage.
Using these events I could wrap `Image` component into something like:
```javascript
class NetworkImage extends React.Component {
getInitialState() {
return {
downloading: false,
progress: 0
}
}
render() {
var loader = this.state.downloading ?
<View style={this.props.loaderStyles}>
<ActivityIndicatorIOS animating={true} size={'large'} />
<Text style={{color: '#bbb'}}>{this.state.progress}%</Text>
</View>
:
null;
return <Image source={this.props.source}
onLoadStart={() => this.setState({downloading: true}) }
onLoaded={() => this.setState({downloading: false}) }
onLoadProgress={(e)=> this.setState({progress: Math.round(100 * e.nativeEvent.written / e.nativeEvent.total)});
onLoadError={(e)=> {
alert('the image cannot be downloaded because: ', JSON.stringify(e));
this.setState({downloading: false});
}}>
{loader}
</Image>
}
}
```
Useful on slow connections and server errors.
There are dozen lines of Objective C, which I don't have experience with. There are neither specific tests nor documentation yet. And I do realize that you're already working right now on better `<Image/>` (pipeline, new asset management, etc.). So this is basically a proof concept of events for images, and if this idea is not completely wrong I could improve it or help somehow.
Closes https://github.com/facebook/react-native/pull/1318
Github Author: Dmitriy Loktev <unknownliveid@hotmail.com>
Alexsander Akers
Dmitriy Loktev
