How to add dividers and spaces between items in RecyclerView?

Question

This is an example of how it could have been done previously in the ListView class, using the divider and dividerHeight parame

Answer 1

Taken from a google search, add this ItemDecoration to your RecyclerView:

public class DividerItemDecoration extends RecyclerView.ItemDecoration {

private Drawable mDivider;
private boolean mShowFirstDivider = false;
private boolean mShowLastDivider = false;


public DividerItemDecoration(Context context, AttributeSet attrs) {
    final TypedArray a = context
            .obtainStyledAttributes(attrs, new int[]{android.R.attr.listDivider});
    mDivider = a.getDrawable(0);
    a.recycle();
}

public DividerItemDecoration(Context context, AttributeSet attrs, boolean showFirstDivider,
        boolean showLastDivider) {
    this(context, attrs);
    mShowFirstDivider = showFirstDivider;
    mShowLastDivider = showLastDivider;
}

public DividerItemDecoration(Drawable divider) {
    mDivider = divider;
}

public DividerItemDecoration(Drawable divider, boolean showFirstDivider,
        boolean showLastDivider) {
    this(divider);
    mShowFirstDivider = showFirstDivider;
    mShowLastDivider = showLastDivider;
}

@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
        RecyclerView.State state) {
    super.getItemOffsets(outRect, view, parent, state);
    if (mDivider == null) {
        return;
    }
    if (parent.getChildPosition(view) < 1) {
        return;
    }

    if (getOrientation(parent) == LinearLayoutManager.VERTICAL) {
        outRect.top = mDivider.getIntrinsicHeight();
    } else {
        outRect.left = mDivider.getIntrinsicWidth();
    }
}

@Override
public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
    if (mDivider == null) {
        super.onDrawOver(c, parent, state);
        return;
    }

    // Initialization needed to avoid compiler warning
    int left = 0, right = 0, top = 0, bottom = 0, size;
    int orientation = getOrientation(parent);
    int childCount = parent.getChildCount();

    if (orientation == LinearLayoutManager.VERTICAL) {
        size = mDivider.getIntrinsicHeight();
        left = parent.getPaddingLeft();
        right = parent.getWidth() - parent.getPaddingRight();
    } else { //horizontal
        size = mDivider.getIntrinsicWidth();
        top = parent.getPaddingTop();
        bottom = parent.getHeight() - parent.getPaddingBottom();
    }

    for (int i = mShowFirstDivider ? 0 : 1; i < childCount; i++) {
        View child = parent.getChildAt(i);
        RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();

        if (orientation == LinearLayoutManager.VERTICAL) {
            top = child.getTop() - params.topMargin;
            bottom = top + size;
        } else { //horizontal
            left = child.getLeft() - params.leftMargin;
            right = left + size;
        }
        mDivider.setBounds(left, top, right, bottom);
        mDivider.draw(c);
    }

    // show last divider
    if (mShowLastDivider && childCount > 0) {
        View child = parent.getChildAt(childCount - 1);
        RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
        if (orientation == LinearLayoutManager.VERTICAL) {
            top = child.getBottom() + params.bottomMargin;
            bottom = top + size;
        } else { // horizontal
            left = child.getRight() + params.rightMargin;
            right = left + size;
        }
        mDivider.setBounds(left, top, right, bottom);
        mDivider.draw(c);
    }
}

private int getOrientation(RecyclerView parent) {
    if (parent.getLayoutManager() instanceof LinearLayoutManager) {
        LinearLayoutManager layoutManager = (LinearLayoutManager) parent.getLayoutManager();
        return layoutManager.getOrientation();
    } else {
        throw new IllegalStateException(
                "DividerItemDecoration can only be used with a LinearLayoutManager.");
    }
}
}