DatePicker Dialog in Java

DatePicker.java

fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // Get Current Date
                final Calendar c = Calendar.getInstance();
                int mYear = c.get(Calendar.YEAR);
                int mMonth = c.get(Calendar.MONTH);
                int mDay = c.get(Calendar.DAY_OF_MONTH);


                DatePickerDialog datePickerDialog = new DatePickerDialog(MainActivity2.this,
                        new DatePickerDialog.OnDateSetListener() {

                            @Override
                            public void onDateSet(DatePicker view, int year,
                                                  int monthOfYear, int dayOfMonth) {

                                dateTextView.setText(dayOfMonth + "-" + (monthOfYear + 1) + "-" + year);

                            }
                        }, mYear, mMonth, mDay);
                datePickerDialog.show();
            }
        });


//DatePicker inside a Dialog
  fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                // get prompts.xml view
                LayoutInflater layoutInflater = LayoutInflater.from(MainActivity2.this);

                View promptView = layoutInflater.inflate(R.layout.dialog_add, null);


                final AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(MainActivity2.this);

                // set prompts.xml to be the layout file of the alertdialog builder
                alertDialogBuilder.setView(promptView);

                final Button dateboughtbookButton=(Button) promptView.findViewById(R.id.calendar_button);

// Show a datepicker when the dateButton is clicked
                dateboughtbookButton.setOnClickListener(new View.OnClickListener() {
                                                            @Override
                                                            public void onClick(View v) {
                                                                //Calendar now = Calendar.getInstance();
                                                                final Calendar c = Calendar.getInstance();

                                                                DatePickerDialog dpd = new DatePickerDialog(MainActivity2.this,
                                                                        new DatePickerDialog.OnDateSetListener() {

                                                                            @Override
                                                                            public void onDateSet(DatePicker view, int year,
                                                                                                  int monthOfYear, int dayOfMonth) {
                                                                                dateboughtbookButton.setText(dayOfMonth + "-"
                                                                                        + (monthOfYear + 1) + "-" + year);

                                                                            }
                                                                        }, c.get(Calendar.YEAR),c.get(Calendar.MONTH),c.get(Calendar.DATE));
                                                                dpd.show();


                                                            }
                                                        }

                );


                alertDialogBuilder
                        .setCancelable(false)
                        .

                                setPositiveButton("Add Alarm",new DialogInterface.OnClickListener() {
                                            @Override
                                            public void onClick (DialogInterface dialog,int id){

                                            }
                                        }

                                )
                        .

                                setNegativeButton("Cancel",
                                        new DialogInterface.OnClickListener() {
                                            public void onClick (DialogInterface dialog,int id){
                                                dialog.cancel();
                                            }
                                        });

                // create an alert dialog
                AlertDialog alertD = alertDialogBuilder.create();

                alertD.show();


            }
        });