public void Fetch(string artUrl, FetchListener listener) {
// WARNING: for the sake of simplicity, simultaneous multi-thread fetch requests
// are not handled properly: they may cause redundant costly operations, like HTTP
// requests and bitmap rescales. For production-level apps, we recommend you use
// a proper image loading library, like Glide.
var bMap = cache [artUrl];
if (bMap != null) {
LogHelper.Debug(Tag, "getOrFetch: album art is in cache, using it", artUrl);
listener.OnFetched(artUrl, bMap[BigBitmapIndex], bMap[IconBitmapIndex]);
return;
}
LogHelper.Debug(Tag, "getOrFetch: starting asynctask to fetch ", artUrl);
Task.Run (async () => {
Bitmap[] bitmaps;
try {
var bitmap = await BitmapHelper.FetchAndRescaleBitmap(artUrl, MaxArtWidth, MaxArtHeight);
var icon = BitmapHelper.Scale(bitmap, MaxArtWidthIcon, MaxArtHeightIcon);
bitmaps = new [] {bitmap, icon};
cache.Put(artUrl, bitmaps);
} catch(IOException) {
return null;
}
LogHelper.Debug(Tag, "doInBackground: putting bitmap in cache. cache size=" + cache.Size());
return bitmaps;
}).ContinueWith ((antecedent) => {
var bitmaps = antecedent.Result;
if (bitmaps == null)
listener.OnError(artUrl, new ArgumentException("got null bitmaps"));
else
listener.OnFetched(artUrl, bitmaps[BigBitmapIndex], bitmaps[IconBitmapIndex]);
}, TaskContinuationOptions.OnlyOnRanToCompletion);
}
public void Fetch(string artUrl, FetchListener listener)
{
// WARNING: for the sake of simplicity, simultaneous multi-thread fetch requests
// are not handled properly: they may cause redundant costly operations, like HTTP
// requests and bitmap rescales. For production-level apps, we recommend you use
// a proper image loading library, like Glide.
Bitmap[] bMap = cache[artUrl];
if (bMap != null)
{
LogHelper.Debug(Tag, "getOrFetch: album art is in cache, using it", artUrl);
listener.OnFetched(artUrl, bMap[BigBitmapIndex], bMap[IconBitmapIndex]);
return;
}
LogHelper.Debug(Tag, "getOrFetch: starting asynctask to fetch ", artUrl);
Task.Run(async() => {
Bitmap[] bitmaps;
try
{
Bitmap bitmap = await BitmapHelper.FetchAndRescaleBitmap(artUrl, MaxArtWidth, MaxArtHeight);
Bitmap icon = BitmapHelper.Scale(bitmap, MaxArtWidthIcon, MaxArtHeightIcon);
bitmaps = new[] { bitmap, icon };
cache.Put(artUrl, bitmaps);
}
catch (IOException)
{
return(null);
}
LogHelper.Debug(Tag, "doInBackground: putting bitmap in cache. cache size=" + cache.Size());
return(bitmaps);
}).ContinueWith((antecedent) => {
var bitmaps = antecedent.Result;
if (bitmaps == null)
{
listener.OnError(artUrl, new ArgumentException("got null bitmaps"));
}
else
{
listener.OnFetched(artUrl, bitmaps[BigBitmapIndex], bitmaps[IconBitmapIndex]);
}
}, TaskContinuationOptions.OnlyOnRanToCompletion);
}
