Android - โค๊ดไดอาล็อก Error อ่ะครับ เหลืออยู่อันเดียวแก้ไม่ได้ (มือใหม่)

package com.no1page;
 
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
//import android.content.DialogInterface.OnClickListener; //error ตรงนี้ด้วยครับ
import android.content.Intent;
 
public class MainActivity extends Activity {
 
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		Button button = (Button)findViewById(R.id.buttonSecond);
		button.setOnClickListener(new View.OnClickListener(){
			
			public void onClick(View v){
				Intent i = new Intent(getApplicationContext(), second.class);
				startActivity(i);
			}
			
		});
	}
	public void onBackPressed(){
		AlertDialog.Builder dialog = new AlertDialog.Builder(this);
		dialog.setTitle("Exit");
		dialog.setIcon(R.drawable.ic_launcher);
		dialog.setCancelable(true);
		dialog.setMessage("Do you want to exit?"); 
		dialog.setPositiveButton("Yes", new DialogInterface.OnClickListener() {      // error dialoginterface.onclicklistener
			public void OnClick(DialogInterface dialog, int which){      // ตัวสีเหลือง OnClick(DialogInterface dialog, int whichlick
				finish();
			}
				
		});
		
		dialog.setNegativeButton("No", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
                dialog.cancel();
            }
        });
		
		dialog.show();
	}
 
}