DividerItemDecoration.java

package com.amaze.filemanager.ui.views;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;

/**
 * Created by Arpit on 23-04-2015.
 */
public class DividerItemDecoration extends RecyclerView.ItemDecoration {

    private static final int[] ATTRS = new int[]{
            android.R.attr.listDivider
    };

    public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;

    public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;

    private Drawable mDivider;

    private int mOrientation;
    private boolean show;
    private int leftpix = 0;
    private boolean showtopbottomdividers;

    public DividerItemDecoration(Context context, int orientation, boolean showtopbottomdividers, boolean show) {
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        a.recycle();
        this.show = show;
        this.showtopbottomdividers = showtopbottomdividers;
        setOrientation(orientation);
        leftpix = (int) (72 * (context.getResources().getDisplayMetrics().densityDpi / 160f));
    }

    public void setOrientation(int orientation) {
        if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) {
            throw new IllegalArgumentException("invalid orientation");
        }
        mOrientation = orientation;
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent) {
        if (!show) return;
        if (mDivider != null)
            if (mOrientation == VERTICAL_LIST) {
                drawVertical(c, parent);
            } else {
                drawHorizontal(c, parent);
            }
    }

    private void drawVertical(Canvas c, RecyclerView parent) {
        final int left = parent.getPaddingLeft() + leftpix;
        final int right = parent.getWidth() - parent.getPaddingRight();

        final int childCount = parent.getChildCount();
        for (int i = showtopbottomdividers ? 0 : 1; i < childCount - 1; i++) {
            final View child = parent.getChildAt(i);
            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                    .getLayoutParams();
            final int top = child.getBottom() + params.bottomMargin;
            final int bottom = top + mDivider.getIntrinsicHeight();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    private void drawHorizontal(Canvas c, RecyclerView parent) {
        final int top = parent.getPaddingTop();
        final int bottom = parent.getHeight() - parent.getPaddingBottom();

        final int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            final View child = parent.getChildAt(i);
            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                    .getLayoutParams();
            final int left = child.getRight() + params.rightMargin;
            final int right = left + mDivider.getIntrinsicHeight();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    @Override
    public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {
        if (outRect != null && mDivider != null)
            if (mOrientation == VERTICAL_LIST) {
                outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
            } else {
                outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
            }
    }

}