RecyclerView styling at theme level

Question

I'm trying to implement generic style parameters for RecyclerView at theme levels. As in contrast to ListView, I used something like this:

Defined a style:

<style name="StyleListView" parent="Widget.AppCompat.ListView">
     <item name="android:requiresFadingEdge">vertical</item>
     <item name="android:fadingEdgeLength">10dp</item>
     <item name="android:scrollbars">vertical</item>
</style>

and later used in my custom theme:

<item name="android:listViewStyle">@style/StyleListView</item>

This works perfectly fine for ListView. However, I'm unable to reflect this for RecyclerView as I thought it would work for any type of list.

So, is there any predefined style attribute available for RecyclerView, for example android:recyclerViewStyle or anything?

If not, then how can I achieve this at theme level?

Answer 1

RecyclerView styling at theme level

RecyclerView now has a default style attribute: recyclerViewStyle, which allows setting of the default style in your theme

The following attributes are supported

    <!-- Class name of the Layout Manager to be used. -->
    <attr name="layoutManager" format="string" />
   
    <!-- ============================= -->
    <!-- Attributes for Layout Manager -->
    <!-- ============================= -->
    <attr name="android:orientation" />
    <attr name="android:descendantFocusability" />
    <attr name="android:clipToPadding" />
    <attr name="spanCount" format="integer"/>
    <attr name="reverseLayout" format="boolean" />
    <attr name="stackFromEnd" format="boolean" />
    <attr name="fastScrollEnabled" format="boolean" />
    <attr name="fastScrollVerticalThumbDrawable" format="reference" />
    <attr name="fastScrollVerticalTrackDrawable" format="reference" />
    <attr name="fastScrollHorizontalThumbDrawable" format="reference" />
    <attr name="fastScrollHorizontalTrackDrawable" format="reference" />

To use the above feature, add/update the following dependency in your build.gradle file.

dependencies {
    implementation 'androidx.recyclerview:recyclerview:1.1.0-beta05'
}

You can see the commit here.

Example:

1. Define your default style

<style name="DefaultRecyclerViewStyle">

    <item name="layoutManager">androidx.recyclerview.widget.GridLayoutManager</item>
    <item name="android:orientation">vertical</item>
    <item name="spanCount">2</item>

</style>

2. Add the above style into your default theme

<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
    <!-- Customize your theme here. -->
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
    <item name="recyclerViewStyle">@style/DefaultRecyclerViewStyle</item>
</style>

Thats, all. You have defined an application wide default style for your RecyclerView widgets.

Answer 2

There's not an equivalent to listViewStyle for RecylerView, unfortunately.

I think the best you can do is define a style for your RecyclerView, then have whichever views you want to use that style use style="@style/RecyclerViewStyle" (if you're just wanting to define a couple attributes like in your example).

If you really just don't want to have to do that for every RecyclerView, then you'd have to subclass it and return a non-zero parameter for defStyle in the constructor. You'd have to replace all instances of your RecyclerView in XML with your newly subclassed class, though.

Answer 3

As @Jason Robinson says you can subclass RecyclerView in this way, replace RecyclerView with RecyclerViewStyleable in xml and then style it with recyclerViewStyle

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="RecyclerViewStyleable">
        <attr name="recyclerViewStyle"/>
    </declare-styleable>
</resources>

-

public class RecyclerViewStyleable extends RecyclerView {
    public RecyclerViewStyleable(Context context) {
        super(context);
    }

    public RecyclerViewStyleable(Context context, AttributeSet attrs) {
        this(context, attrs, R.attr.recyclerViewStyle);
    }

    public RecyclerViewStyleable(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }
}