带有自定义适配器的listview总是在获取listview项名称时崩溃

问题出在标题上。我有一个带有自定义适配器的listview。当我试图获取listview中显示的listview项的名称时，系统崩溃。我怎样才能解决它

public class MenuPrincipalCiudades extends ListActivity {

    private AlphabetListAdapter adapter = new AlphabetListAdapter();
    private GestureDetector mGestureDetector;
    List<Row> rows;
    private List<Object[]> alphabet = new ArrayList<>();
    private HashMap<String, Integer> sections = new HashMap<String, Integer>();
    private int sideIndexHeight;
    private static float sideIndexX;
    private static float sideIndexY;
    private int indexListSize;

    private ProgressDialog pDialog;
    JSONArray ciudades = null;
    JSONObject c;
    ListView lv;
    boolean esCancelado = false;
    ArrayList<String> listaCiudades;


    class SideIndexGestureListener extends GestureDetector.SimpleOnGestureListener {
        @Override
        public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
            sideIndexX = sideIndexX - distanceX;
            sideIndexY = sideIndexY - distanceY;

            if (sideIndexX >= 0 && sideIndexY >= 0) {
                displayListItem();
            }

            return super.onScroll(e1, e2, distanceX, distanceY);
        }
    }


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.list_alphabet);
        lv = (ListView) findViewById(android.R.id.list);
        listaCiudades = new ArrayList<>();

        mGestureDetector = new GestureDetector(this, new SideIndexGestureListener());
        listaCiudades.add("New York");
        listaCiudades.add("Panama");
        listaCiudades.add("Spain");
        aplicarEstilo();

        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> a, View v, int position, long id) {
                AlphabetListAdapter.Section obj_itemDetails = (AlphabetListAdapter.Section) adapter.getItem(position);
                Toast.makeText(MenuPrincipalCiudades.this, "You have chosen : " + " " + obj_itemDetails.text, Toast.LENGTH_LONG).show();

            }
        });

    }






    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if (mGestureDetector.onTouchEvent(event)) {
            return true;
        } else {
            return false;
        }
    }

    public void aplicarEstilo(){
        Collections.sort(listaCiudades);

        rows = new ArrayList<>();
        int start = 0;
        int end = 0;
        String previousLetter = null;
        Object[] tmpIndexItem = null;
        Pattern numberPattern = Pattern.compile("[0-9]");

        for (String country : listaCiudades) {
            String firstLetter = country.substring(0, 1);

            // Group numbers together in the scroller
            if (numberPattern.matcher(firstLetter).matches()) {
                firstLetter = "#";
            }

            // If we've changed to a new letter, add the previous letter to the alphabet scroller
            if (previousLetter != null && !firstLetter.equals(previousLetter)) {
                end = rows.size() - 1;
                tmpIndexItem = new Object[3];
                tmpIndexItem[0] = previousLetter.toUpperCase(Locale.UK);
                tmpIndexItem[1] = start;
                tmpIndexItem[2] = end;
                alphabet.add(tmpIndexItem);
                start = end + 1;
            }

            // Check if we need to add a header row
            if (!firstLetter.equals(previousLetter)) {
                rows.add(new Section(firstLetter));
                sections.put(firstLetter, start);
            }

            // Add the country to the list
            rows.add(new Item(country));
            previousLetter = firstLetter;
        }

        if (previousLetter != null) {
            // Save the last letter
            tmpIndexItem = new Object[3];
            tmpIndexItem[0] = previousLetter.toUpperCase(Locale.UK);
            tmpIndexItem[1] = start;
            tmpIndexItem[2] = rows.size() - 1;
            alphabet.add(tmpIndexItem);
        }

        adapter.setRows(rows);
        setListAdapter(adapter);

        updateList();
    }

    public void updateList() {
        LinearLayout sideIndex = (LinearLayout) findViewById(R.id.sideIndex);
        sideIndex.removeAllViews();
        indexListSize = alphabet.size();
        if (indexListSize < 1) {
            return;
        }

        int indexMaxSize = (int) Math.floor(sideIndex.getHeight() / 20);
        int tmpIndexListSize = indexListSize;
        while (tmpIndexListSize > indexMaxSize) {
            tmpIndexListSize = tmpIndexListSize / 2;
        }
        double delta;
        if (tmpIndexListSize > 0) {
            delta = indexListSize / tmpIndexListSize;
        } else {
            delta = 1;
        }

        TextView tmpTV;
        for (double i = 1; i <= indexListSize; i = i + delta) {
            Object[] tmpIndexItem = alphabet.get((int) i - 1);
            String tmpLetter = tmpIndexItem[0].toString();

            tmpTV = new TextView(this);
            tmpTV.setText(tmpLetter);
            tmpTV.setGravity(Gravity.CENTER);
            tmpTV.setTextSize(15);
            LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT, 1);
            tmpTV.setLayoutParams(params);
            sideIndex.addView(tmpTV);
        }

        sideIndexHeight = sideIndex.getHeight();

        sideIndex.setOnTouchListener(new OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                // now you know coordinates of touch
                sideIndexX = event.getX();
                sideIndexY = event.getY();

                // and can display a proper item it country list
                displayListItem();

                return false;
            }
        });
    }

    public void displayListItem() {
        LinearLayout sideIndex = (LinearLayout) findViewById(R.id.sideIndex);
        sideIndexHeight = sideIndex.getHeight();
        // compute number of pixels for every side index item
        double pixelPerIndexItem = (double) sideIndexHeight / indexListSize;

        // compute the item index for given event position belongs to
        int itemPosition = (int) (sideIndexY / pixelPerIndexItem);

        // get the item (we can do it since we know item index)
        if (itemPosition < alphabet.size()) {
            Object[] indexItem = alphabet.get(itemPosition);
            int subitemPosition = sections.get(indexItem[0]);
            getListView().setSelection(subitemPosition);
        }
    }

}

谢谢你帮助我

因为adapter.getItem（position）方法返回Item not节。因此，你必须改变路线

AlphabetListAdapter.Section obj_itemDetails = (AlphabetListAdapter.Section) adapter.getItem(position);

到

---

卓越的奥佐！谢谢你帮助我

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <ListView
        android:id="@android:id/list"
        android:scrollbars="none"
        android:layout_width="0dp"
        android:overScrollMode="never"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:dividerHeight="7.0sp"
        android:paddingLeft="10dp"
        android:paddingRight="10dp"
        android:paddingBottom="10dp"
        android:divider="#eeeeee"
        android:fastScrollEnabled="true" />

    <LinearLayout
        android:id="@+id/sideIndex"
        android:layout_width="40dip"
        android:layout_height="fill_parent"
        android:background="#FFF"
        android:gravity="center_horizontal"
        android:orientation="vertical" >
    </LinearLayout>

</LinearLayout>

java.lang.ClassCastException: mypackage.AlphabetListAdapter$Item cannot be cast to mypackage.AlphabetListAdapter$Section

AlphabetListAdapter.Section obj_itemDetails = (AlphabetListAdapter.Section) adapter.getItem(position);

AlphabetListAdapter.Item obj_itemDetails = (AlphabetListAdapter.Item) adapter.getItem(position);