LayoutManagers.java

package me.tatarka.bindingcollectionadapter2;

import android.support.annotation.IntDef;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

/**
 * A collection of factories to create RecyclerView LayoutManagers so that you can easily set them
 * in your layout.
 */
public class LayoutManagers {
    protected LayoutManagers() {
    }

    public interface LayoutManagerFactory {
        RecyclerView.LayoutManager create(RecyclerView recyclerView);
    }

    /**
     * A {@link LinearLayoutManager}.
     */
    public static LayoutManagerFactory linear() {
        return new LayoutManagerFactory() {
            @Override
            public RecyclerView.LayoutManager create(RecyclerView recyclerView) {
                return new LinearLayoutManager(recyclerView.getContext());
            }
        };
    }

    /**
     * A {@link LinearLayoutManager} with the given orientation and reverseLayout.
     */
    public static LayoutManagerFactory linear(@Orientation final int orientation, final boolean reverseLayout) {
        return new LayoutManagerFactory() {
            @Override
            public RecyclerView.LayoutManager create(RecyclerView recyclerView) {
                return new LinearLayoutManager(recyclerView.getContext(), orientation, reverseLayout);
            }
        };
    }

    /**
     * A {@link GridLayoutManager} with the given spanCount.
     */
    public static LayoutManagerFactory grid(final int spanCount) {
        return new LayoutManagerFactory() {
            @Override
            public RecyclerView.LayoutManager create(RecyclerView recyclerView) {
                return new GridLayoutManager(recyclerView.getContext(), spanCount);
            }
        };
    }

    /**
     * A {@link GridLayoutManager} with the given spanCount, orientation and reverseLayout.
     **/
    public static LayoutManagerFactory grid(final int spanCount, @Orientation final int orientation, final boolean reverseLayout) {
        return new LayoutManagerFactory() {
            @Override
            public RecyclerView.LayoutManager create(RecyclerView recyclerView) {
                return new GridLayoutManager(recyclerView.getContext(), spanCount, orientation, reverseLayout);
            }
        };
    }

    /**
     * A {@link StaggeredGridLayoutManager} with the given spanCount and orientation.
     */
    public static LayoutManagerFactory staggeredGrid(final int spanCount, @Orientation final int orientation) {
        return new LayoutManagerFactory() {
            @Override
            public RecyclerView.LayoutManager create(RecyclerView recyclerView) {
                return new StaggeredGridLayoutManager(spanCount, orientation);
            }
        };
    }

    @IntDef({LinearLayoutManager.HORIZONTAL, LinearLayoutManager.VERTICAL})
    @Retention(RetentionPolicy.SOURCE)
    public @interface Orientation {
    }
}