Package com.bumptech.glide

Interface ListPreloader.PreloadModelProvider<U>

Type Parameters:
U - The type of the model being preloaded.
Enclosing class:
ListPreloader<T>
public static interface ListPreloader.PreloadModelProvider<U>
An implementation of PreloadModelProvider should provide all the models that should be preloaded.

  • Method Details

    • getPreloadItems

      @NonNull List<U> getPreloadItems(int position)
      Returns a List of models that need to be loaded for the list to display adapter items in positions between start and end.

      position is the position in the view. If the view contains a mix of types (e.g. headers and images) then not every view position will actually have any model to return here. If that's the case for the given position, then return an empty list.

      A list of any size can be returned so there can be multiple models per adapter position.

      Every model returned by this method is expected to produce a valid RequestBuilder in getPreloadRequestBuilder(Object). If that's not possible for any set of models, avoid including them in the List returned by this method.

      Although it's acceptable for the returned List to contain null models, it's best to filter them from the list instead of adding null to avoid unnecessary logic and expanding the size of the List

      Parameters:
      position - The adapter position.

    • getPreloadRequestBuilder

      @Nullable RequestBuilder<?> getPreloadRequestBuilder(@NonNull U item)
      Returns a RequestBuilder for a given item on which RequestBuilder.load(Object)} has been called or null if no valid load can be started.

      For the preloader to be effective, the RequestBuilder returned here must use exactly the same size and set of options as the RequestBuilder used when the ``View`` is bound. You may need to specify a size in both places to ensure that the width and height match exactly. If so, you can use BaseRequestOptions.override(int, int) to do so.

      The target and context will be provided by the preloader.

      If RequestBuilder.load(Object) is not called by this method, the preloader will trigger a RuntimeException. If you don't want to load a particular item or position, filter it from the list returned by getPreloadItems(int).

      Parameters:
      item - The model to load.