how to pass variables to another activity using intent?

Question

I'm trying to build a simple cookie clicker- you press a button a variable grows by 1. Now, I'm trying to build a shop, so you can buy upgrades-the variable grows more, auto clicks... So, I'm trying to pass my variables (number of cookies, cookies for click) using intent, but every time I try to get to the activity, my app crash. here is my MainActivity code:

public static int NumOfCookies=0;
public static int CookieForClick=1;
public final static String EXTRA_MESSAGE = "com.example.cookieclicker01";
public final static String EXTRA_INTENT = "com.example.cookieclicker01";

public void GetToShop(View v){
    Intent intent = new Intent(this, ShopActivity.class);
    Bundle extras = new Bundle();
    intent.putExtra(EXTRA_MESSAGE, NumOfCookies);
    intent.putExtra(EXTRA_INTENT, CookieForClick);
    intent.putExtras(extras);
    startActivity(intent);
}

here is my code for the second activity:

        Intent intent = getIntent();
     var1= intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
     var2 = intent.getStringExtra(MainActivity.EXTRA_INTENT);
    NumOfCookies= Integer.parseInt(var1);
    CookiesForClick= Integer.parseInt(var2);
    TextView t1= (TextView) findViewById(R.id.Cookies);
    t1.setText(Integer.toString(NumOfCookies));

Answer 1

You are trying to get a String, but your var1 , and var2 are int values.

var1= intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
 var2 = intent.getStringExtra(MainActivity.EXTRA_INTENT);

The correct is :

var1= intent.getInt(MainActivity.EXTRA_MESSAGE);
var2 = intent.getInt(MainActivity.EXTRA_INTENT);

Or your will change the type of var1, var2 to String:

public static String NumOfCookies=0;
public static String CookieForClick=1;

Answer 2

either this -

//Bundle extras = new Bundle();
intent.putExtra(EXTRA_MESSAGE, NumOfCookies);
intent.putExtra(EXTRA_INTENT, CookieForClick);
//intent.putExtras(extras);

Comment out those two lines. Basically you were putting a empty Bundle in your intent in the last line and thus replacing your previously stored values.

or that-

    Bundle extras = new Bundle();
    extras.putString(EXTRA_MESSAGE, NumOfCookies);
    extras.putString(EXTRA_INTENT, CookieForClick);
    intent.putExtras(extras);