how to achieve something like "finish" in a non-activity class in android?

Question

This dialog asks whether you want to install some other app...so when onclicked no button it must go back to the previous screen

    downloadDialog.setNegativeButton(stringButtonNo,
            new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialogInterface, int i) {
                         finish();
                }
            });

this gives the error:

The method finish() is undefined for the type new DialogInterface.OnClickListener(){}

how can i achieve what i wanted???

package com.Android.barcode;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;

public class BarcodeActivity extends Activity {
    public static String upc;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        IntentIntegrator.initiateScan(this);
    }

    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch (requestCode) {
        case IntentIntegrator.REQUEST_CODE: {
            if (resultCode != RESULT_CANCELED) {
                IntentResult scanResult = IntentIntegrator.parseActivityResult(
                        requestCode, resultCode, data);
                if (scanResult != null) {
                    upc = scanResult.getContents();

                    Intent intent = new Intent(BarcodeActivity.this, BarcodeResult.class);
                    startActivity(intent);
                    // put whatever you want to do with the code here
/*                  TextView tv = new TextView(this);
                    tv.setText(upc);
                    setContentView(tv);*/
                }
            }
            break;
        }
        }
    }
}

Answer 1

Since you don't want to create that dialog from that activity : You have two options

1) Call an Intent back to the activity you want the user to go to.

Intent intent = new Intent(getBaseContext(), theActivity.class); 
getApplication().startActivity(intent) ;

or Else

2) Create a constructor for that class consisting of the dialog.

public class ABC {
    Context iContext=null;
   public ABC(Context con){
    iContext=con;
   }
 ....

}

Call the class with the Context of the activity. Like ABC(Cont) .And then use ((Activity)iContext).finish() within that class to finish that activity as you wish.