Dialog example in android

I want to display a dialog when a button is clicked. Here is my code, but it does not work.

AlertDialog.Builder builder = new AlertDialog.Builder(
                        getApplicationContext());
                builder.setCancelable(true);
                builder.setTitle("Title");
                builder.setInverseBackgroundForced(true);
                builder.setPositiveButton("Yes",
                        new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog,
                                    int which) {
                                dialog.dismiss();
                            }
                        });
                builder.setNegativeButton("No",
                        new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog,
                                    int which) {
                                dialog.dismiss();
                            }
                        });
                AlertDialog alert = builder.create();
                alert.show();