Question

In my android application I want to solve the following scenario.

class Login extends Activity {
   @Override
     public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
         LayoutBuilder  objLB=new LayoutBuilder(this);
         objLB.createSpinner();
    } 

    public void spinnerItemSelectedEvent(AdapterView<?> parent, View view,
        int pos, long id)
    {
    }
}



class LayoutBuilder {
    private Activity objActivity;

    public LayoutBuilder(Activity a) {
        objActivity = a; 
    }

    public void createSpinner() {
        final Spinner objSPItem = new Spinner(objActivity);
        objSPItem.setOnItemSelectedListener(
            new Spinner.OnItemSelectedListener() {
                public void onItemSelected(AdapterView<?> parent, View view,
                    int pos, long id)
                {
                    // Do some common activity 
                    objActivity.spinnerItemSelectedEvent(parent,view,pos,id);
                    // calling this for do some additional task
                }
                public void onNothingSelected(AdapterView<?> arg0) {}
        });
        objActivity.spinnerItemSelectedEvent()
    }
}

and the problem is when i try to access spinnerItemSelectedEvent(parent,view,pos,id) from the ‘onItemSelected’ listner inside createSpinner method
I got the following error.

The method spinnerItemSelectedListener(AdapterView, View, int, long) is undefined for the type Activity

but out side the listner the access to the method works ok(neglect parameter list). What is the reason behind that? is any alternate way exist for solving this? plz help

Answer 1

Activity in android represents a screen. You are making a variable objActivity of type Activity whereas it should be of type Login where the function spinnerItemSelectedEvent() is declared. Change the following lines:

private Activity  objActivity;

to

private Login  objActivity;

and your code should run.

EDIT

Have a BaseActivity and let all your other activities extend this BaseActivity. To make the function spinnerItemSelectedEvent() reusable declare it in the BaseActivity and you can use it the way you are trying to do it now.

Example:

class BaseActivity extends Activity{
    public void spinnerItemSelectedEvent(AdapterView<?> parent, View view,
    int pos, long id){ }
} 

  class Login extends BaseActivity{
   public void spinnerItemSelectedEvent(AdapterView<?> parent, View view,
    int pos, long id){ //Local implementation of the function}
}

class LayoutBuilder {
private BaseActivity objActivity;

}