This tutorial briefly describes the use of RecyclerViews in an MVC component. For the
prerequisites to this tutorial, see Additional Resources.
Using RecyclerViews in a basic way in MVC is now very similar to how basic non-recycler
lists work. The general flow is as follows:
- Build and maintain a
ModelList. - Create a
SimpleRecyclerViewAdapter. - Register each type of view with the adapter.
- Clean up recycled views if necessary.
Both the ModelListAdapter and the SimpleRecyclerViewAdapter implement the
MVCListAdapter interface. That is to say that usage of the two adapters is roughly identical.
The main reason to use one or the other is dependent on the capabilities needed by the views that
each adapter is attached to. Changing from using a ListView to a RecyclerView should be
simple once the adapter is implemented.
A SimpleRecyclerViewAdapter is instantiated the same way a ModelListAdapter is; you
only need to provide a handle to the ModelList for the data the view will display.
Typical usage of RecyclerView requires the creation of a ViewHolder to cache the views
that frequently have new content bound to them. The SimpleRecyclerViewAdapter does away with
this concept.
A generic solution to fast view lookup can be found in
ViewLookupCachingFrameLayout. This version of a
FrameLayout exposes a method: fastFindViewById. The added method attempts to find the
specified view, and if it exists, it will be cached for faster lookups. See the full documentation
for this class here.
In some cases complex views can hold on to expensive resources; the most common cases is holding a
reference to a large bitmap. The SimpleRecyclerViewAdapter does not explicitly provide a way
to do resource cleanup, but this can still be achieved with RecyclerView#RecyclerListener.
recyclerListener = (holder) -> {
// Do cleanup for |holder| here. The root view can be accessed via |holder#itemView|
};
// Optionally the listener can be defined in-line below.
mRecyclerView.setRecyclerListener(recyclerListener);