Change a Public Float Value within a Menu [Android]

Basically I am making an app where there is a Ball On the screen and the size of the ball is determined by this code

I hope you get what i mean , but if someone could assist me on creating this menu type thing it would be great !

             **UPDATE :**

Here is the开发者_高级运维 current Menu

private static final int Small= 1;


     public boolean onCreateOptionsMenu(Menu menu) {
        ((Activity) menu).onCreateOptionsMenu(menu);

        menu.add(0, Small, 0, "Small");

       return true;

    }
     public boolean onOptionsItemSelected(MenuItem item) {
            switch (item.getItemId()) {
                case Small:


                   // here i want it to change the size down to something like 0.009f

                    return true;
            }
            return false;
     }

    public   float sBallDiameter = 0.013f;

Basically - What i want to do is make it so when the case "Small" is selected - it decreases the size of "sBallDiameter"

• I hope that clears things up a bit more -

Use Enum instead of fixed size

public Enum BallSize{

  SMALL(0.09f),MEDIUM(0.11f),LARGE(0.018f);

  BallSize(float size)
  {
    this.size=size;
  }

  private final float size;
}

And after user changes menu compare the menu item with Ballsize

Here is how you create menus: Creating Menus.

Define you menu in a res/menu/ball_menu.xml file:

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:id="@+id/menu_small"
          android:icon="@drawable/ic_menu_small"
          android:title="@string/small" />
</menu>

Then in your activity:

private static final float SMALL_SIZE = 0.1f;
private static final float BIG_SIZE = 0.3f;
private float mBallSize = SMALL_SIZE;

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.ball_menu, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle item selection
    switch (item.getItemId()) {
    case R.id.menu_small:
        setBallSize(SMALL_SIZE);
    default:
        return super.onOptionsItemSelected(item);
    }
}

private void setBallSize(float size) {
    this.mBallSize = size;
}