Avoid Glide target re-use when loading the same image into the same view #6898
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If all the models and properties are the same, Glide just re-triggers the previous target. This causes issues with .NET and Task and async/await, so we set the callback (which is unique on each run) as a fallback image. This effectively makes each request unique so targets are not reused (but still uses the cache).
mattleibow
added
t/bug
| // A special value to work around https://github.com/dotnet/maui/issues/6783 where targets | ||
| // are actually re-used if all the variables are the same. | ||
| // Adding this "error image" that will always load a null image makes each request unique, | ||
| // but does not affect the various caching levels. | ||
| builder = builder | ||
| .error(callback); |
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This is the real-magic. We set the error image as the callback instance so it will always create a unique load path.
It is magic because we actually say "if there is an error, load the java object callback from C# as the image". This may seem weird, but we need a way to mark each builder as unique but strings and ints mean things. So the next best is just a java object we already know is unique.
Now since we can't actually load a java interface as an image on screen :) we need to add the loaders that handle these callbacks and just skip the work.
| // trigger the callback out of this target | ||
| post(() -> callback.onComplete(false, errorDrawable, this::clear)); |
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Callbacks have to be on the post because if you try load a second image right after the first one, then you are still in the callback because the TaskCompletionSource.SetResult() continues on the same thread and thus all the code in C# that follows is effectively in the target still - which is not a Glide-supported operation.
| // add workaround loader for https://github.com/dotnet/maui/issues/6783 | ||
| registry.prepend(ImageLoaderCallback.class, ImageLoaderCallback.class, new ImageLoaderCallbackModelLoaderFactory()); |
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Since we added the callback as a fallback image, to avoid runtime errors in the log about unable to load the callback as an image, we create a dummy model loader that basically returns null.
Eilon
added
area-controls-image
Description of Change
If all the models and properties are the same, Glide just re-triggers the previous target.
This causes issues with .NET and Task and async/await, so we set the callback (which is unique on each run) as a fallback image. This effectively makes each request unique so targets are not reused (but still uses the cache).
Issues Fixed
Fixes #6783
This is potentially the real cause of #6464 so we may need to revisit the eager cleanups
Testing
Since all the changes are in the java code, you can simply replace the maui.aar in the workload install folders and watch the magic happen.