Question

I have a piece of code to delete an Item in database. I am calling the same code from two different activities. So to avoid code repetition, I want to shift the code to the Application object. The code in one of the activities looks like this:

private void deleteItem() {
    AlertDialog.Builder alert = new AlertDialog.Builder(Activity1.this);
    alert.setTitle(R.string.confirmTitle);
    alert.setMessage(R.string.confirmMessage);
    alert.setPositiveButton(R.string.delete_btn,
            new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int button) {
                    final DbHelper db = new DbHelper(Activity1.this);
                    AsyncTask<Long, Void, Object> deleteTask = new AsyncTask<Long, Void, Object>() {
                        @Override
                        protected Object doInBackground(Long... params) {
                            db.deleteItem(params[0]);
                            return null;
                        }

                        @Override
                        protected void onPostExecute(Object result) {
                            finish();
                        }
                    };
                    deleteTask.execute(new Long[] { rowID });
                }
            });
    alert.setNegativeButton(R.string.cancel_btn, null).show();
}

Now to put it in application object, I changed the function to public, gave it two parameters for input: Context and rowID. But in the onPostExecute method of AsyncTask I have to close the activity. In the activity, I did this by finish(). How do I do it in this context? I have attached the code in application object also.

public void deleteItem(final Context context, final long rowID) {
    AlertDialog.Builder alert = new AlertDialog.Builder(context);
    alert.setTitle(R.string.confirmTitle);
    alert.setMessage(R.string.confirmMessage);
    alert.setPositiveButton(R.string.delete_btn,
            new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int button) {
                    final DbHelper db = new DbHelper(context);
                    AsyncTask<Long, Void, Object> deleteTask = new AsyncTask<Long, Void, Object>() {
                        @Override
                        protected Object doInBackground(Long... params) {
                            db.deleteItem(params[0]);
                            return null;
                        }

                        @Override
                        protected void onPostExecute(Object result) {
                            finish();
                            }
                    };
                    deleteTask.execute(new Long[] { rowID });
                }
            });
    alert.setNegativeButton(R.string.cancel_btn, null).show();
}

Answer 1

I think that what you are trying to do is fundamentally not a good idea.

Outside of the Activity code, there are no guarantees that the activity still exists – the memory manager may have cleaned it up, the user may have pressed Back etc.

The final design decision is up to you but I advise you to consider if this is really necessary.

A little redundancy is okay in my opinion if it leads to more program stability and reliability.