An ItemDecoration implementation for RecyclerView android widget

DividerItemDecoration.java

package com.vadim.zasovin.workout.widget;

import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.RecyclerView.ItemDecoration;
import android.support.v7.widget.RecyclerView.LayoutManager;
import android.support.v7.widget.RecyclerView.State;
import android.view.View;

public class DividerItemDecoration extends ItemDecoration {
	
	private int mDividerHeight;
	private int mColor;
	
	private int mOffsets;
	private int mAdjustedOffsets;
	private boolean mToAdjustOffsets = false;

	
	
	/**
	 * Create new DividerItemDecoration with the specified height and color
	 * without additional offsets
	 */
	public DividerItemDecoration(int dividerHeight, int color) {
		mDividerHeight = dividerHeight;
		mColor = color;
		mOffsets = mDividerHeight;
	}
	
	

	/**
	 * Create new DividerItemDecoration with the specified height, color and offsets between
	 * elements. Offsets can not be less than divider height.
	 */
	public DividerItemDecoration(int dividerHeight, int color, int offsets, boolean adjustOffsets) {
		super();
		
		if(offsets < dividerHeight){
			throw new IllegalArgumentException("Offsets can not be less than divider height");
		}else if(adjustOffsets){
			mToAdjustOffsets = true;
			mAdjustedOffsets = (offsets - dividerHeight)/2;
		}
			
		mOffsets = offsets;
		mDividerHeight = dividerHeight;
		mColor = color;
	}

	
	
	/**
	 * Create new DividerItemDecoration without any decor
	 */
	public DividerItemDecoration() {
		super();
		mDividerHeight = 1;
		mColor = 0x8a000000;
	}



	@Override
	public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
			State state) {
		
		LayoutManager layoutManager = parent.getLayoutManager();
		if(layoutManager == null){
			throw new RuntimeException("LayoutManager not found");
		}
		if(layoutManager.getPosition(view) != 0)
			outRect.top = mOffsets;
	}

	@Override
	public void onDraw(Canvas c, RecyclerView parent, State state) {
		
	}

	@Override
	public void onDrawOver(Canvas c, RecyclerView parent, State state) {

		Paint paint = new Paint();
		paint.setColor(mColor);
		
		int left = parent.getPaddingLeft();
		int right = left + parent.getWidth()-parent.getPaddingRight();
		
		for(int i = 0;i<parent.getChildCount();i++){
			
			View child = parent.getChildAt(i);
			
			int top = 0;
			//try to place divider in the middle of the space between elements
			if(!mToAdjustOffsets)
				top = child.getBottom();
			else top = child.getBottom() + mAdjustedOffsets;
			int bottom = top + mDividerHeight;
			
			c.drawRect(left, top, right, bottom, paint);
		}
	}

}