删除项目后Android ListView出现问题

Question

I seem to be having a problem with Android ListView. I'm trying to delete the selected item from ListView. The delete method is working and will allow me to delete as many items from my list as needed, but whenever I scroll to the bottom of the list (after atleast 1 item has been deleted) I get an Error that closes the Application.

Here is my code:

public class MainActivity extends Activity {

   private String[] mRoute;

   @Override
   public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.main);

     mRoute = getResources().getStringArray(R.array.countries);

     ListView list = (ListView)findViewById(R.id.list);

     ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, R.layout.listitem,     mRoute);

     list.setAdapter(adapter);

     registerForContextMenu(list);
  }

  @Override
  public boolean onContextItemSelected(MenuItem item) {

        AdapterView.AdapterContextMenuInfo info  (AdapterView.AdapterContextMenuInfo)item.getMenuInfo();
        int menuItemIndex = item.getItemId();
        String[] menuItems = getResources().getStringArray(R.array.menu);
        String menuItemName = menuItems[menuItemIndex];
        String listItemName = mRoute[info.position];

        // Remove String From List  
        List<String> routeArrayString = new ArrayList<String>(Arrays.asList(mRoute));
    routeArrayString.remove(listItemName);
    mRoute = routeArrayString.toArray(mRoute);

        //Generate new ListView
        ListView list = (ListView)findViewById(R.id.list);
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, R.layout.listitem, mRoute);
    list.setAdapter(adapter);   
    registerForContextMenu(list);

        return true;

        }

Any ideas? Thanks in advance.

Answer 1

What error happens? Anyway your code is little bit ugly and this should be written in another way. You should work with your adapter because it is like a bridge between you ListView and actual data. The BasicAdapter has special methods for notifying about data changes, just inherit your own adapter and manipulate with data directly through adapter.

Answer 2

I think adding items to the Array in my adapter was the problem.

public class MainActivity extends ListActivity {

    private ArrayAdapter<String> dataAdapter;
    private static final int REMOVE_ITEM = 1;

    private String[] mRoute = {"One", "Two", "Three", "Four", "Five"};

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        dataAdapter = new ArrayAdapter<String>(this, R.layout.list_item, R.id.itemName);

        for (int i = 0; i < mRoute.length; i++) {
             dataAdapter.add(mRoute[i]);
        }

        setListAdapter(dataAdapter);


    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu)
    {
        Resources resource = getApplicationContext().getResources();
        menu.add(Menu.NONE,REMOVE_ITEM, REMOVE_ITEM, "REMOVE ITEM");

        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item)
    {
        switch (item.getItemId())
        {
        case REMOVE_ITEM:
            dataAdapter.remove(dataAdapter.getItem(dataAdapter.getCount() - 1));
            break;
        }
        return false;
    }


}

Works!