在Xamarin Android中如何通过FFImageLoading将图片加载至内存？

Hey there! Let's dig into your FFImageLoading code and that caching behavior you're noticing where images only seem to cache to disk.

First off, let's look at your current code snippet:

ImageService.Instance.LoadUrl(item.profileImg) 
    .DownSample() 
    .BitmapOptimizations(true) 
    .LoadingPlaceholder("blank_profile_img.png", FFImageLoading.Work.ImageSource.CompiledResource) 
    .Into(holder.imgIcon);

Default Caching Behavior #

By default, FFImageLoading uses a two-level cache system: it keeps images in both memory (for fast, repeated access) and disk (for persistence across app restarts). If you're only seeing disk caching happen, here are a few things to check and adjust:

1. Explicitly Enable Memory Caching #

While memory cache is on by default, sometimes explicit settings can help ensure it's working for this specific request. Add the .CacheMemory(true) method to your chain to lock in memory caching:

ImageService.Instance.LoadUrl(item.profileImg) 
    .DownSample() 
    .BitmapOptimizations(true)
    .CacheMemory(true) // Force memory caching for this image
    .LoadingPlaceholder("blank_profile_img.png", FFImageLoading.Work.ImageSource.CompiledResource) 
    .Into(holder.imgIcon);

2. Check Global App Configuration #

If memory caching still isn't kicking in, double-check your app's global FFImageLoading setup (usually in your startup code like App.xaml.cs). Make sure memory cache isn't disabled globally:

ImageService.Instance.Initialize(new Configuration {
    MemoryCacheSize = 1024 * 1024 * 50, // Set a reasonable memory cache limit (50MB here)
    EnableMemoryCache = true // Confirm this is set to true
});

3. If You Want Only Disk Cache (Double-Check) #

Wait, if your intention is actually to only use disk cache (and skip memory), your current code might already be doing that if memory cache was disabled elsewhere. But to explicitly enforce it, you can add .CacheMemory(false):

ImageService.Instance.LoadUrl(item.profileImg) 
    .DownSample() 
    .BitmapOptimizations(true)
    .CacheMemory(false) // Disable memory caching entirely
    .LoadingPlaceholder("blank_profile_img.png", FFImageLoading.Work.ImageSource.CompiledResource) 
    .Into(holder.imgIcon);

Quick Troubleshooting Tips #

• Restart your app between tests—memory cache can stick around during debug sessions, making it hard to test changes.
• Use ImageService.Instance.InvalidateMemoryCache() to manually clear the memory cache if you need to start fresh.
• If your images are larger than the configured memory cache limit, FFImageLoading might skip storing them in memory to avoid bloat. Adjust the MemoryCacheSize if that's the case.

内容的提问来源于stack exchange，提问作者Jim Layhey