从微调器 onItemSelected 更改微调器选项

Question

我在顶部有一个旋转器，显示圣经书籍。选择一本书后，我会找出其中有多少章并将其放入 Chapters 变量中。然后我想根据有多少章来更改名为 bible_chapters 的微调器。

public class Find extends Fragment {

    private Spinner bibleBooks;
    private Spinner bibleChapters;
    private Spinner bibleVerses;
    private boolean spinnerInitialized;

    public Find() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        final View rootView = inflater.inflate(R.layout.fragment_find, container, false);
        final DatabaseManager databaseAccess = DatabaseManager.getInstance(getActivity());
        final Context con = getContext();

        // Spinner Listener
        bibleBooks = rootView.findViewById(R.id.bible_books);
        bibleChapters = rootView.findViewById(R.id.bible_chapters);

        bibleBooks.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
                if (!spinnerInitialized) {
                    spinnerInitialized = true;
                    return;
                }

                databaseAccess.open();
                String book = adapterView.getSelectedItem().toString();
                int Chapters = databaseAccess.howManyChapters(book);
                databaseAccess.close();
                Log.d("Chapters",String.valueOf(Chapters));
                if(Chapters > 1) {

                    List<String> newChapters = new ArrayList<String>();
                    for (int x = 2; x <= Chapters; x++) {
                        newChapters.add("Chapter " + x);
                    }
                    ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(con, bibleBooks, newChapters);
                    bibleBooks.setAdapter(arrayAdapter);
                }

            }
            public void onNothingSelected(AdapterView<?> adapterView) {
                return;
            }
        });


        // Inflate the layout for this fragment
        return rootView;
    }

}

错误在ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(con, bibleBooks, newChapters);行。问题出在上下文上。我试过：

this,

rootView,

getContext(),

getActivity(),

我不断收到的错误是： error: no suitable constructor found for ArrayAdapter(Context,Spinner,List<String>)

None 似乎正是它要找的东西。我哪里错了？

Answer 1

请尝试在 ArrayAdapter

的 Constructor 中使用 getActivity() 而不是 getContext()

 ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(getActivity(), bibleBooks, newChapters);
                    bibleBooks.setAdapter(arrayAdapter);

希望对您有所帮助

Answer 2

在Xamarin.Android中我总是传递spinnerItem，例如Android.Resource.Layout.SimpleSpinnerItem

ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(con, Android.Resource.Layout.SimpleSpinnerItem, newChapters);

而不是 *bibleBooks *，这是微调器本身。

编辑：对于 Java：android.R.layout.simple_spinner_item

Answer 3

在代码new ArrayAdapter<String>(con, bibleBooks, newChapters),中，第二个参数必须是资源ID。例如，new ArrayAdapter<String>(con, R.layout.item_spinner, newChapters);

和R.layout.item_spinner：

<TextView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    xmlns:tools="http://schemas.android.com/tools"
    android:drawableEnd="@drawable/ic_spinner"
    android:drawablePadding="4dp"
    android:drawableRight="@drawable/ic_spinner"
    android:gravity="right"
    android:padding="8dp"
    android:textColor="@color/colorPrimary"
    android:textSize="14dp" />

Answer 4

你的尝试是错误的。

ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(con, bibleBooks, newChapters);

您正在传递 spinner 对象而不是 layout resource id 。尝试下面它适合你。

ArrayAdapter<String> adapter=new ArrayAdapter<String>(context,R.layout.support_simple_spinner_dropdown_item,newChapters);

从微调器 onItemSelected 更改微调器选项

Change spinner options from spinner onItemSelected

android

spinner

android-studio-3.0