I am struggling to make it so that an int decided by the user is available in different activities

Question

I am creating an app to test the user on their knowledge on certain subjects. For each test they will get a score. There score is an int, (finalscore) but I am struggling to make it so that finalscore is visible in other activities. Any help would be much appreciated.

Answer 1

Try using a singleton extending your Application.

public class GlobalVars extends Application {
  private int finalscore = 0;

  int getPoints() { return finalscore; }
  void setPoints(final int newpoints) { finalscore = newpoints; }

  ...
}

So if you have to get or set values for that int, just use:

GlobalVars globvars = ((GlobalVars) getApplicationContext());
globvars.setPoints(5);

This is "project-wide", so you can call it in any Activity.

Answer 2

You can pass the integer to the next activity by adding it as an extra :

Intent nextActivity = new Intent(CurrentActivity.this,NextActivity.class);
nextActivity.putExtra("finalscore",finalScore);
startActivity(nextActivity);

Then in the next activity, get the score by using :

int finalScore = getIntent().getIntExtra("finalscore", 0);

Notice that the string "finalscore" is the same in the two activities. You can use a constant to be sure not to make mistakes.

Answer 3

You should be passing the int between activities

When you open a new activity

 Intent intent = new Intent("MY ACTION");
 intent.putExtra("MY_INT_KEY", intValue);
 startActivity(intent);

And in onCreate of the next activity

 getIntent().getExtras().getInt("MY_INT_KEY");

Answer 4

To make some value visible to all activities from your app, you can also use SharedPreferences. These store key-value pairs.

1. Saving

   //create prefs object, "myprefs" is just a file name where your values will be stored
   SharedPreferences prefs = getSharedPreferences("myprefs", Context.MODE_PRIVATE);
   SharedPreferences.Editor editor = prefs.edit();
   
   //store your integer
   editor.putInt("score", scoreValue);
   
   //save
   editor.commit();
   

2. Reading - can be done in any activity

   //create prefs object, "myprefs" is just a file name where your values will be stored
   SharedPreferences prefs = getSharedPreferences("myprefs", Context.MODE_PRIVATE);
   
   //read the value for key "score", and assign to the variable
   int score = prefs.getInt("score", 0);  //<------ 0 here is default value in case "score" key doesn't exist, you can replace it with any value
   

More info here.