int positionGlobal = 0;
.............................

	btnNext.setOnClickListener(new OnClickListener() {

				@Override
				public void onClick(View arg0) {
					// TODO Auto-generated method stub
					next();
				}
			});

	      btnPrev.setOnClickListener(new OnClickListener() {

				@Override
				public void onClick(View arg0) {
					// TODO Auto-generated method stub
					prev();
				}
			});

listview.setOnItemClickListener(new OnItemClickListener() {

			@Override
			public void onItemClick(AdapterView<?> arg0, View arg1, int position,
					long id) {

					positionGlobal = position;
					spurl = portfolioArrayList.get(positionGlobal).getUrl().toString();
	    				spname = portfolioArrayList.get(positionGlobal).getTitle().toString();
						textTrack.setText(spname);
					}
				});
			}


public void next(){
            if(positionGlobal < portfolioArrayList.size()) {
            	positionGlobal = positionGlobal+1;
            spurl = portfolioArrayList.get(positionGlobal).getUrl().toString();
	    spname = portfolioArrayList.get(positionGlobal).getTitle().toString();
			textTrack.setText(spname);
            } else
	   	}
          }

public void prev(){
		   if(positionGlobal > 0) {
		     positionGlobal = positionGlobal-1;
		      spurl = portfolioArrayList.get(positionGlobal).getUrl().toString();
		      spname = portfolioArrayList.get(positionGlobal).getTitle().toString();

				textTrack.setText(spname);
		    } else if(positionGlobal == 0) {
		    	Toast.makeText(PortfolioActivity.this, "Already there !", Toast.LENGTH_LONG).show();
		    }

	   }