選中標籤後刷新片段

Question

構建片段時，我從本地數據庫中的信息構建視圖。其他選項卡可以修改此信息，並且當用戶選擇選項卡時，我希望反映新信息。

public class RunningTotal extends SherlockFragment { 
    public static final String TAG = "Running Total"; 
    private LinearLayout lv; 

    public View onCreateView(LayoutInflater li, ViewGroup vg, 
      Bundle savedInstanceState) { 
     SalesDataSource sds = BarcodeSaleTracker.SDS; 

     ArrayList<Item> items = sds.getAllItems(); 
     String[] totals = sds.getPersonValues(); 
     int totalsPosition = 0; 
     Log.v(TAG, "Items Length: " + items.size()); 

     lv = new LinearLayout(this.getActivity()); 

     String lastPerson = ""; 

     if (items.size() > 0) { 
      for (Item i : items) { 
       if (lastPerson.equalsIgnoreCase(i.getPerson()) == false) { 
        lastPerson = i.getPerson(); 
        TextView tv = (TextView) li.inflate(R.layout.list_title, 
          lv, false); 
        tv.setText(totals[totalsPosition]); 
        totalsPosition++; 
        lv.addView(tv); 
       } 

       TextView listItem = (TextView) li.inflate(R.layout.list_item, 
         lv, false); 
       listItem.setText(i.toString()); 
       lv.addView(listItem); 
      } 
     } else { 
      TextView noItems = (TextView) li.inflate(R.layout.list_title, lv, 
        false); 
      noItems.setText(R.string.no_items); 
      lv.addView(noItems); 
     } 

     return lv; 
    } 
} 

這是一個標籤格式，幾乎等同於夏洛特例如：

public class BarcodeSaleTracker extends SherlockFragmentActivity { 
    TabHost mTabHost; 
    ViewPager mViewPager; 
    TabsAdapter mTabsAdapter; 

    public static SalesDataSource SDS; 

    public BarcodeSaleTracker() { 

    } 

    protected void onCreate(Bundle savedInstanceState) { 
     setTheme(R.style.Sherlock___Theme); 
     super.onCreate(savedInstanceState); 

     SDS = new SalesDataSource(this); 
     SDS.open(); 

     if (savedInstanceState == null) { 
      setContentView(R.layout.fragment_tabs_pager); 

      mTabHost = (TabHost) findViewById(android.R.id.tabhost); 
      mTabHost.setup(); 

      mViewPager = (ViewPager) findViewById(R.id.pager); 

      mTabsAdapter = new TabsAdapter(this, mTabHost, mViewPager); 

      mTabsAdapter.addTab(mTabHost.newTabSpec("current_sale") 
        .setIndicator("Current Sale"), Current_Sale.class, null); 
      mTabsAdapter.addTab(mTabHost.newTabSpec("running_total") 
        .setIndicator("Running Total"), RunningTotal.class, null); 
      mTabsAdapter.addTab(
        mTabHost.newTabSpec("stats").setIndicator("Stats"), 
        CountingFragment.class, null); 
     } else { 
      mTabHost.setCurrentTabByTag(savedInstanceState.getString("tab")); 
     } 
    } 

我只是不知道如何向它需要更新自己RunningTotal通信。

編輯添加了所有的數據源我從數據庫中問

public class SalesDataSource { 
    private SQLiteDatabase database; 
    private DatabaseHelper dbHelper; 
    private String[] allColumns = { DatabaseHelper.COLUMN_ID, 
      DatabaseHelper.COLUMN_PERSON, DatabaseHelper.COLUMN_COST, 
      DatabaseHelper.COLUMN_ITEM }; 

    public SalesDataSource(Context context) { 
     dbHelper = new DatabaseHelper(context); 
    } 

    public void open() throws SQLException { 
     database = dbHelper.getWritableDatabase(); 
    } 

    public void close() { 
     dbHelper.close(); 
    } 

    /** 
    * Creates an entry in the Database. Both a person and a cost are required. 
    * Item is not required. If one is not needed, simply pass null. 
    * 
    * @param person 
    *   Who this sale belongs to. 
    * @param cost 
    *   The amount (in pennies) that the sale was. 
    * @param item 
    *   An optional description of the sold item 
    * @return The newly created Item. 
    */ 
    public Item addItem(String person, int cost, String item) { 
     ContentValues values = new ContentValues(); 

     values.put(DatabaseHelper.COLUMN_PERSON, person); 
     values.put(DatabaseHelper.COLUMN_COST, cost); 
     values.put(DatabaseHelper.COLUMN_ITEM, item); 

     long insertId = database.insert(DatabaseHelper.TABLE_SALES, null, 
       values); 

     Cursor cursor = database.query(DatabaseHelper.TABLE_SALES, allColumns, 
       DatabaseHelper.COLUMN_ID + " = " + insertId, null, null, null, 
       null); 

     cursor.moveToFirst(); 
     Item rv = cursorToItem(cursor); 
     cursor.close(); 

     return rv; 
    } 

    public void addItems(List<Item> items) { 
     for (Item i : items) { 
      ContentValues values = new ContentValues(); 

      values.put(DatabaseHelper.COLUMN_PERSON, i.getPerson()); 
      values.put(DatabaseHelper.COLUMN_COST, i.getAmount()); 
      values.put(DatabaseHelper.COLUMN_ITEM, i.getItem()); 

      database.insert(DatabaseHelper.TABLE_SALES, null, values); 
     } 
    } 

    public ArrayList<Item> getAllItems() { 
     ArrayList<Item> items = new ArrayList<Item>(); 

     Cursor cursor = database.query(DatabaseHelper.TABLE_SALES, allColumns, 
       null, null, null, null, DatabaseHelper.COLUMN_PERSON); 

     cursor.moveToFirst(); 

     while (!cursor.isAfterLast()) { 
      Item item = cursorToItem(cursor); 
      items.add(item); 
      cursor.moveToNext(); 
     } 

     cursor.close(); 

     return items; 
    } 

    public String[] getPersonValues() { 
     Cursor cursor = database.query(DatabaseHelper.TABLE_SALES, 
       new String[] { "SUM(" + DatabaseHelper.COLUMN_COST + ") AS " + DatabaseHelper.PERSON_SUM, 
         DatabaseHelper.COLUMN_PERSON }, null, null, 
       DatabaseHelper.COLUMN_PERSON, null, null); 
     String[] rv = new String[cursor.getCount()]; 

     cursor.moveToFirst(); 
     int pos = 0; 
     while (!cursor.isAfterLast()) { 
      String person = cursor.getString(1); 
      String money = Item.format(cursor.getInt(0)); 
      rv[pos++] = person + ": " + money; 
      cursor.moveToNext(); 
     } 

     cursor.close(); 

     return rv; 
    } 

    public Item getMaxSale() { 
     Cursor cursor = database.query(DatabaseHelper.TABLE_SALES, 
       new String[] { "MAX(" + DatabaseHelper.COLUMN_COST + ") AS " + DatabaseHelper.MAX_SALE, 
         DatabaseHelper.COLUMN_PERSON }, null, null, null, null, 
       null); 

     cursor.moveToFirst(); 


     Item rv = cursorToItem(cursor); 
     cursor.close(); 
     return rv; 

    } 

    public Item getMinSale() { 
     Cursor cursor = database.query(DatabaseHelper.TABLE_SALES, 
       new String[] { "MIN(" + DatabaseHelper.COLUMN_COST + ") AS " + DatabaseHelper.MIN_SALE, 
         DatabaseHelper.COLUMN_PERSON }, null, null, null, null, 
       null); 

     cursor.moveToFirst(); 

     Item rv = cursorToItem(cursor); 
     cursor.close(); 
     return rv; 

    } 

    private Item cursorToItem(Cursor cursor) { 
     Item item = new Item(); 

     item.setId(cursor.getLong(0)); 
     item.setPerson(cursor.getString(1)); 
     item.setAmount(cursor.getInt(2)); 
     item.setItem(cursor.getString(3)); 

     return item; 
    } 
} 

Answer 1

爲什麼不使用listfragment和loadermanager管理光標對象，以便列表每當基礎數據的變化而自動更新？