IssueTracker

androidx.recyclerview:recyclerview:1.2.0-alpha03

First of all, thank you for the new MergeAdapter! This is my first time using and benefiting from it.

When I create a merge adapter configuration via MergeAdapter.Config.Builder().build(), I receive a configuration with Config::isolateViewTypes set to false. The value of this same field in MergeAdapter.Config::DEFAULT is true.

This violated the principle of least surprise for me. I was evolving code that initially used "no" (= the default) configuration:

mAdapter = MergeAdapter(adapter1, adapter2)

I wanted to update this code to change the stable ID mode. I tried to achieve that by building and passing in a custom configuration:

mAdapter = MergeAdapter(
    MergeAdapter.Config.Builder()
        .setStableIdMode(ISOLATED_STABLE_IDS)
        .build(),
    adapter1,
    adapter2
)

but this temporarily broke my code because view type isolation changed compared to the initial code. I instead needed to explicitly write

mAdapter = MergeAdapter(
    MergeAdapter.Config.Builder()
        .setIsolateViewTypes(true)
        .setStableIdMode(ISOLATED_STABLE_IDS)
        .build(),
    adapter1,
    adapter2
)

to retain default view type isolation behavior.

Please evaluate whether it would be less surprising to initialize

private boolean mIsolateViewTypes = true;

in MergeAdapter.Config::Builder instead!