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&nbsp;AdapterView.OnItemSelectedListener()&nbsp;{ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Override &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;public&nbsp;void&nbsp;onItemSelected(AdapterView<?>&nbsp;parent,&nbsp;View&nbsp;view,&nbsp;int&nbsp;position,&nbsp;long&nbsp;id)&nbsp;{ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;String&nbsp;str&nbsp;=&nbsp;collegeSpinner.getSelectedItem().toString(); &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;} &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Override &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;public&nbsp;void&nbsp;onNothingSelected(AdapterView<?>&nbsp;parent)&nbsp;{ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;String&nbsp;str&nbsp;=&nbsp;llist.get(0); &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;} &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;});