Question

Can i initialize object in my first activity and you it in all activity???

public class Calc{
    int x;
    int y;
    public Calc(int x, int y) {
       this.x = x;
       this.y = y;
    }
    public int sum() {
        return x + y;
    }
}
public class MainActivity extends Activity {

private int progressStatus = 0;
private Handler handler = new Handler();
private ProgressBar loading;
private static int progress;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);


    Calc c = new Calc(3, 4);
}
}


public class PreviewActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.preview);

            TextView txt = (TextView) findViewById(R.id.txt);
            txt.setText(Integer.toString(c.sum));
}
}

How can i Initialize Calc object in MainActivity and use it PreviewActivity.

How can i pass it to another activity or how can i make it share with other activity

Answer 1

Use Application class by extending it and writing your custom Application class, and keep your objects in this class that you need in your cross Activities

class MyApplication extends Application{
    Object a;

    public void setA(Object a){
         this.a = a;
    }

    public Object getA(){
         return a;
    }

}

Now lets suppose in your A activity you create object of class Object and want to use it in your B Activity.

do it this way,

class ActivityA extends Activity(){

...
// some where in activity, set your object this way.
     Object aObj = new Object();
     ((MyApplication)getApplication()).setA(aObj);


...

}

class ActivityB extends Activity(){

...
// some where in activity, get your object this way.
     Object aObj = ((MyApplication)getApplication()).getA( );


...

}

You need to tell your androidManifest.xml about your extended Application class.