Getting a Spinner's selected item without causing a java.NullPointerException

Question

I am trying to make an AlertDialog that pops up and has a Spinner in it where someone can select an item, and that item is saved to a variable. However, when I'm testing it out, and I click the OK Button, the app stops, and I get a java.NullPointerException on logcat. Apparently, the Spinner's getSelectedItem() (which is supposed to get the chosen item) is causing this java.NullPointerException .

The code that is causing the NullPointerException:

 alertDialogBuilder.setView(promptsView);
                    alertDialogBuilder
                            .setCancelable(false)
                            .setPositiveButton("OK",
                                    new DialogInterface.OnClickListener() {
                                        public void onClick(DialogInterface dialog,int id) {


                                            final Spinner spinner = (Spinner) findViewById(R.id.LanguagePicker);
                                            /*(error is here) -->*/ text = spinner.getSelectedItem().toString(); 



                                            spinner.setAdapter(adapter);
                                            String r = textInput.getText().toString();
                                            allTheTranslatedText = getTranslatedText(r);
                                            textOutput.setText(allTheTranslatedText);
                                        }
                                    })
                            .setNegativeButton("Cancel",
                                    new DialogInterface.OnClickListener() {
                                        public void onClick(DialogInterface dialog, int id) {
                                            dialog.cancel();
                                        }
                                    });
                    AlertDialog alertDialog = alertDialogBuilder.create();
                    alertDialog.show();


            }
        });

Is there another way you can use retrieve the Spinner's selected item without causing a NullPointerException?

Answer 1

Do like this.

You are missing promptsView.findViewById();

final Spinner spinner = (Spinner) promptsView.findViewById(R.id.LanguagePicker);

View promptsView = LayoutInflator.inflator(......//do it);
alertDialogBuilder.setView(promptsView);
                    alertDialogBuilder
                            .setCancelable(false)
                            .setPositiveButton("OK",
                                    new DialogInterface.OnClickListener() {
                                        public void onClick(DialogInterface dialog,int id) {

                                            //this is the main line
                                            final Spinner spinner = (Spinner) promptsView.findViewById(R.id.LanguagePicker);
                                            /*(error is here) -->*/ text = spinner.getSelectedItem().toString(); 



                                            spinner.setAdapter(adapter);
                                            String r = textInput.getText().toString();
                                            allTheTranslatedText = getTranslatedText(r);
                                            textOutput.setText(allTheTranslatedText);
                                        }
                                    })
                            .setNegativeButton("Cancel",
                                    new DialogInterface.OnClickListener() {
                                        public void onClick(DialogInterface dialog, int id) {
                                            dialog.cancel();
                                        }
                                    });
                    AlertDialog alertDialog = alertDialogBuilder.create();
                    alertDialog.show();


            }
        });