单击时，微调器选择的项目未显示

Question

我添加了一个从房间数据库中检索数据的微调器，当我点击微调器时它正确地显示了可用的项目，但是当我选择一个时它不会在微调器中显示为选中并且不显示任何内容我发现即使我选择了某些东西，也不会触发collegeSpinner.setOnItemSelectedListener    ArrayAdapter<String> adapter;     CollegeViewModel collegeViewModel;     Spinner collegeSpinner;     @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_add_note);         collegeSpinner = (Spinner) findViewById(R.id.spinner_college);         final ArrayList<String> collegesList = new ArrayList<>();         final CollegeAdapter collegeAdapter = new CollegeAdapter();         collegeViewModel = ViewModelProviders.of(this).get(CollegeViewModel.class);         collegeViewModel.getAllColleges().observe(this, new Observer<List<College>>() {             @Override             public void onChanged(List<College> colleges) {                 //this is what happens when when data changes // the code bellow should be related to changing the view                 collegeAdapter.setColleges(colleges);  // getting colleges from database and assigning it to collegeadapter                 for (int i = 0; i < collegeAdapter.getItemCount(); i++) { // accessing the adapter to add it's elements to collegeList                     collegesList.add(collegeAdapter.getCollegeAt(i).getCollegeName());                 }             }         });         adapter = new ArrayAdapter<>(getApplicationContext(), R.layout.small_view, collegesList);         collegeSpinner.setAdapter(adapter);         collegeSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {             @Override             public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {                 // this function doesn't work even when i select something             }             @Override             public void onNothingSelected(AdapterView<?> adapterView) {                 // also doesn't work             }         });     }

Answer 1

collegeSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                String str = collegeSpinner.getSelectedItem().toString();
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
                String str = llist.get(0);
            }
        });