How to access instance variable and method in main activity from other activity? [duplicate]

Question

Possible Duplicate:
Android: How to declare global variables?

I want to access public instance variable in main activity from other activity. And I want to call public method in main activity. How can I do that?

class MainActivity extends Activity {
    public int i;
    public void myMethod() {}
}

class MyActivity extends Activity {
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // How can I access variable i in MainActivity?
        // And How can I call myMethod() in MainActivity?
    }
}

Orabîg · Accepted Answer · 2012-08-30 14:30:02Z

3

This is not recommended, as your activity class may be recycled by the system at any time.

Use preferences to store variables, or simplier : create your own Application class. This one will be available during all the application life, and you'll be able to store static variable in it.

answered Aug 30, 2012 at 14:30

Orabîg

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Adam Monos · Accepted Answer · 2012-08-30 14:36:18Z

3

You can pass it as an extra in the Intent with wich you start your new Activity.

answered Aug 30, 2012 at 14:36

Adam Monos

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1 Comment

Jeff Bootsholz Over a year ago

We can also use Parcelables to pass the Plain Class

Community · Accepted Answer · 2017-05-23 12:09:27Z

1

This might help you: How to declare global variables in Android?

You can use a subclass of Application, SharedPreferences or static variables.

edited May 23, 2017 at 12:09

CommunityBot

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answered Aug 30, 2012 at 14:32

Aerilys

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Comments

InflexCZE · Accepted Answer · 2012-08-30 14:42:38Z

1

Try this

class MainActivity extends Activity {
    public int i;
void startNewA()
{
 Intent i = new Intent(getApplicationContext(), MyActivity.class);
 i.putExtra("var_name", i);
 startNewActivity(i);
}
}

class MyActivity extends Activity {
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        int i = getIntent().getIntExtra("var_name", -1);
    }
}

answered Aug 30, 2012 at 14:42

InflexCZE

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1 Comment

user1301568 Over a year ago

This is just good for one or two variables to share. But, I have a lot of variables to share.

Mr.S · Accepted Answer · 2012-08-30 14:30:33Z

0

When you want to get and set the same variabl in more than one activity you could also use the prferences.

answered Aug 30, 2012 at 14:30

Mr.S

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