codes for CollageView

 Use This code to get the library-

 com.jcmore2.collage:collage:1.0.0

Use this code in covert to convert The cardview to Collageview - 

com.jcmore2.collage.CollageView

Use this code in oncreate - 

CollageView collage = (CollageView) findViewById(R.id.collage);

		List<Integer> listRes = new ArrayList<Integer>();
		listRes.add(R.drawable.img1);
		listRes.add(R.drawable.img2);
		listRes.add(R.drawable.img3);
		listRes.add(R.drawable.img4);
		
		collage.createCollageResources(listRes);