FATAL EXCEPTION: main? Android

package com.example.ecomm;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.LinearLayout.LayoutParams;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
       
final LinearLayout layout = (LinearLayout)findViewById(R.id.linearMain);
final Button btn = (Button)findViewById(R.id.second);

final Controller ct = (Controller) getApplicationContext();
        
        
 ModelProducts products = null; 
 
         for(int i= 1; i<=7;i++){
        	 
        	  int Price = 15+ i;
        	  
        	  products = new ModelProducts("Product Item" +i, "Description"+i, Price);
        	 
        	  ct.setProducts(products);
         }
        
         
         int productsize = ct.getProductArraylistsize();
         
         LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
         
         
         for (int j=0;j< productsize;j++){
        	 
        	 
        	String pName = ct.getProducts(j).getProductName(); 
        	int pPrice = ct.getProducts(j).getProductPrice();
        	
        	
        	 LinearLayout la = new LinearLayout(this);
        	
        	 la.setOrientation(LinearLayout.HORIZONTAL);
        	    
        	 TextView tv = new TextView(this);
        	 
        	 tv.setText(" "+pName+" ");
        	 
        	 la.addView(tv);
        	    
             TextView tv1 = new TextView(this);
        	 
        	 tv1.setText("$"+pPrice+" ");
        	 
        	 la.addView(tv1);
        	 
        	  final Button btn1 = new Button(this);
        	  
        	               btn1.setId(j+1);
        	               btn1.setText("Add to Cart");
        	               
        	     
        	        btn1.setLayoutParams(params);
        	        
        	   final int index = j;
        	   
        	   btn1.setOnClickListener(new OnClickListener() {
				
				public void onClick(View v) {
					// TODO Auto-generated method stub
					
					
					Log.i("TAG", "index:"+index);
					
					
					ModelProducts productsObject = ct.getProducts(index);
					
					
					if(!ct.getCart().CheckProductInCart(productsObject)){
					
					btn1.setText("Item Added");
					
					ct.getCart().setProducts(productsObject);
							
					Toast.makeText(getApplicationContext(), "New CartSize:" +ct.getCart().getCartsize(),Toast.LENGTH_LONG).show();		
							
					}else{
						
				    Toast.makeText(getApplicationContext(), "Products"+(index+1)+"Already Added",Toast.LENGTH_LONG ).show();
						
						 
						
						
						
					   }
							
				}	
					
		});
        	               
        	 la.addView(btn1);
        	 
        	 layout.addView(la);
        	   
        	   
          }
         
         btn.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				
				Intent in = new Intent(getBaseContext(),Screen2.class);
				 startActivity(in);
				
				
				
			}
		});
        
    }
}

<linearlayout xmlns:android="http://schemas.android.com/apk/res/android">
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" 
    android:orientation="vertical"
    
    >
    
    <textview>
        android:layout_width="wrap_removed"
        android:layout_height="wrap_removed"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:textColor="#898989"
        android:textStyle="bold"
        android:textSize="18sp"
        android:text="GreenBerry" />
    
    <linearlayout>
        android:layout_width="match_parent"
	    android:layout_height="wrap_content"
	    android:orientation="vertical"
	    android:id="@+id/linearMain"
	    >
	    
     </linearlayout>   
    <Button android:id="@+id/second"
           android:layout_width="wrap_content"
           android:layout_height="wrap_content"
           android:text="Checkout"
	/>