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

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?
    }
}

score 3 · Answer 1 · answered Aug 30 '12 at 14:30

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.

score 3 · Answer 2 · answered Aug 30 '12 at 14:36

3

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

answered Aug 30 '12 at 14:36

Adam Monos

4,287
1
23
25

We can also use Parcelables to pass the Plain Class – Jeff Bootsholz Jul 16 '13 at 01:36

score 1 · Accepted Answer · edited May 23 '17 at 12:09

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 '17 at 12:09

Community

1
1

answered Aug 30 '12 at 14:32

Aerilys

1,628
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score 1 · Answer 4 · answered Aug 30 '12 at 14:42

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 '12 at 14:42

InflexCZE

722
1
14
30

This is just good for one or two variables to share. But, I have a lot of variables to share. – user1301568 Aug 31 '12 at 22:11

score 0 · Answer 5 · answered Aug 30 '12 at 14:30

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 '12 at 14:30

Mr.S

94
9

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

5 Answers5