IssueTracker

Definitely want to support this. Currently investigating moving the Callbacks to interfaces so that wrapping/conversion can be done:

    private abstract class WrapperDataSource<in A, B>(private val source: PositionalDataSource<A>)
            : PositionalDataSource<B>() {
        override fun loadInitial(params: LoadInitialParams, callback: LoadInitialCallback<B>) {
            source.loadInitial(params, object: LoadInitialCallback<A> {
                override fun onResult(data: List<A>, position: Int, totalCount: Int) {
                    callback.onResult(convert(data), position, totalCount)
                }

                override fun onResult(data: List<A>, position: Int) {
                    callback.onResult(convert(data), position)
                }
            })
        }

        override fun loadRange(params: LoadRangeParams, callback: LoadRangeCallback<B>) {
            source.loadRange(params) { data -> callback.onResult(convert(data)) }
        }

        protected abstract fun convert(source: List<A>): List<B>
    }

Making them interfaces makes it easy to wrap/test. Downside is that external callers can't use some of the guts of the callback impl (like validating non-negative positions), but this should make it much more reasonable to wrap, decorate, or otherwise post-process data loaded from e.g. Room. In the network case, the equivalent might be post-processing a network request in a way that's awkward to inject into network loading code.

Fixed internally by making Params constructors public, and Callbacks abstract. Will go out with next alpha release.

We're also investigating making it easier to wrap and do decoration/type conversions, since the example in #2 mostly works, but is incomplete - it needs to handle invalidates.

Released: https://developer.android.com/topic/libraries/architecture/release-notes.html#paging

Project: platform/frameworks/support
Branch: androidx-master-dev

commit 3d6aa2e9b3243dcc4de1f54bd8d40339bd69cb05
Author: Seigo Nonaka <nona@google.com>
Date:   Wed May 27 17:38:05 2020

    Adjust the Typeface display style with the style of given font
   
    This behavir is implicitly done by Typeface.Builder and
    Typeface.createXXX function but not to be done by
    Typeface.CustomFallbackBuilder since it is designed to be working
    with multiple font files which has different style.
   
    Looks like the style argument is ignored on older API implementation.
   
    Bug: 156853883
    Bug: 152023266
    Test: ResourcesCompatTest#testGetFont_adjustDisplayStyle passes on 29
    Test: ./gradlew core:core:connectedAndroidTest on API 29, 28, 23
    Change-Id: I3a377c339a7aed50973cf11df86ddf0069f4ec25

A       core/core/src/androidTest/assets/fonts/thin_italic.ttf
A       core/core/src/androidTest/assets/fonts/thin_italic.ttx
M       core/core/src/androidTest/java/androidx/core/content/res/ResourcesCompatTest.java
A       core/core/src/androidTest/res/font/thin_italic.ttf
M       core/core/src/main/java/androidx/core/graphics/TypefaceCompatApi29Impl.java

https://android-review.googlesource.com/1318947