基于datepicker更改从数据库中重新加载listView内容

Question

我将开始说这是一个2部分问题。我有一个带有3个按钮和listView的活动。一个按钮打开一个带有datepicker的对话范围，并且按钮文本显示所选日期。其他两个按钮允许您分别进入前几天。ListView应显示与所选日期相对应的记录。

当前，加载活动时，按钮显示了今天的日期，ListView显示了今天的数据库记录。我设法创建了一种重新启动加载程序并在上一个/下一个按钮中调用的方法，因此，当一次每天导航时，ListView更新以显示正确的记录，但是当我通过调用DatePicker更改日期时对话框，我似乎找不到使它正确更新的方法 - 这是问题的第一部分。

第二部分很难解释。当我选择一个带有4个记录的日期（ListView中的4行）时，所有4个记录显示，但是例如，如果我转到第二天，只有2个记录（列表视图中的2行），它将正确显示第一个记录2个记录，但是接下来的2行仍然显示上一个日期的数据。为了更好地解释这一点，让我们假设ListView中的每一行显示DB Records _id号码。在日期1（有4个记录），我有ID 1,2,3,4显示，但是在更改日期2（有2个记录）时，它显示ID 5,6,3,4。

我假设通过合并一种可以完全清除listView内容的方法，然后重新流动新日期，我可以一次解决这两个问题。我只是不确定该怎么做。我的代码如下：

public class FuncLogbook extends ListActivity implements
LoaderManager.LoaderCallbacks<Cursor>, OnItemClickListener {        
Button btn_logbook_date;
LogDateDialogFragment fragDate;
Calendar now;
Date nowD, newD, PrevDate, NextDate;
int lMonth;
String strDate;
private SimpleCursorAdapter adapter;        
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView (R.layout.dash_logbook);     
    this.getListView().setDividerHeight(2);         
    ListView list = getListView();
    list.setOnItemClickListener(this);
    btn_logbook_date = (Button) findViewById(R.id.btn_logbook_date);
    now = Calendar.getInstance();
    nowD = now.getTime();
    SimpleDateFormat dFormatter = new SimpleDateFormat("dd MMM yyyy");
    strDate = dFormatter.format(nowD);
    btn_logbook_date.setText(strDate);              
    fillData();             
}       
public void modifyDate(View v) {
    int id = v.getId ();
    switch (id) {
    case R.id.btn_logbook_date :
        showDialogDate();
        break;
    case R.id.btn_logbook_prev :
        updateDatePrev();
        break;
    case R.id.btn_logbook_next :
        updateDateNext();
        break;
    }   
}
public interface LogDateDialogFragmentListener {
    public void logbookChangedDate(int year, int month, int day);
}
public void showDialogDate() {
    FragmentTransaction ftLogDate = getFragmentManager().beginTransaction();
    fragDate = LogDateDialogFragment.newInstance(this, new LogDateDialogFragmentListener() {
        public void logbookChangedDate(int year, int month, int day) {          
            now.set(Calendar.YEAR, year);
            now.set(Calendar.MONTH, month);
            now.set(Calendar.DAY_OF_MONTH, day);
            newD = now.getTime();
            SimpleDateFormat newDFormatter = new SimpleDateFormat("dd MMM yyyy");
            strDate = newDFormatter.format(newD);
            btn_logbook_date.setText(strDate);
        }}, now);
    fragDate.show(ftLogDate, "DateDialogFragment");     
}
public void updateDatePrev() {
    String prevVar[] = btn_logbook_date.getText().toString().split(" ");
    if (prevVar[1].equalsIgnoreCase("Jan")) {
        lMonth = 0;
    } else if (prevVar[1].equalsIgnoreCase("Feb")) {
        lMonth = 1;
    } else if (prevVar[1].equalsIgnoreCase("Mar")) {
        lMonth = 2;
    } else if (prevVar[1].equalsIgnoreCase("Apr")) {
        lMonth = 3;
    } else if (prevVar[1].equalsIgnoreCase("May")) {
        lMonth = 4;
    } else if (prevVar[1].equalsIgnoreCase("Jun")) {
        lMonth = 5;
    } else if (prevVar[1].equalsIgnoreCase("Jul")) {
        lMonth = 6;
    } else if (prevVar[1].equalsIgnoreCase("Aug")) {
        lMonth = 7;
    } else if (prevVar[1].equalsIgnoreCase("Sep")) {
        lMonth = 8;
    } else if (prevVar[1].equalsIgnoreCase("Oct")) {
        lMonth = 9;
    } else if (prevVar[1].equalsIgnoreCase("Nov")) {
        lMonth = 10;
    } else if (prevVar[1].equalsIgnoreCase("Dec")) {
        lMonth = 11;
    }
    int lYear = Integer.parseInt(prevVar[2]);
    int lDay = Integer.parseInt(prevVar[0]);
    now = Calendar.getInstance();
    now.set(Calendar.YEAR, lYear);
    now.set(Calendar.MONTH, lMonth);
    now.set(Calendar.DAY_OF_MONTH, lDay - 1);
    PrevDate = now.getTime();
    SimpleDateFormat prevDFormatter = new SimpleDateFormat("dd MMM yyyy");
    strDate = prevDFormatter.format(PrevDate);
    btn_logbook_date.setText(strDate);
    refillData();       
}
public void updateDateNext() {
// Same as updateDatePrev() method, but moves forward 1 day, instead of backward
}
protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
    super.onActivityResult(requestCode, resultCode, intent);
}
private void fillData() {       
    String[] from = new String[] { AddDBHelper.KEY_BGL, AddDBHelper.KEY_ROWID,
            AddDBHelper.KEY_CATEG, AddDBHelper.KEY_TIME };
    int[] to = new int[] {R.id.logBGL, R.id.logRowID, R.id.logCateg, R.id.logTime };
    getLoaderManager().initLoader(0, null, this);
    adapter = new SimpleCursorAdapter(this, R.layout.logbook_item, null, from, to, 0);
    setListAdapter(adapter);
}
private void refillData() { 
    getLoaderManager().restartLoader(0, null, this);        
}
public Loader<Cursor> onCreateLoader(int id, Bundle args) { 
     String selection = AddDBHelper.KEY_DATE + "=?";
     String[] selectionArgs = { String.valueOf(btn_logbook_date.getText().toString()) };
    CursorLoader cl = new CursorLoader(this, DBProvider.CONTENT_URI,
            null, selection, selectionArgs, null);
    return cl;
}
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
    adapter.swapCursor(data);
}
public void onLoaderReset(Loader<Cursor> loader) {
    // data is not available anymore; delete reference
    adapter.swapCursor(null);
}
}

update

从ContentProvider显示查询信息：

@Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
        String sortOrder) {
    // Using SQLiteQueryBuilder instead of query() method
    SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();     
    // Set the DB table to query
    queryBuilder.setTables(AddDBHelper.DB_TABLE);
    int uriType = sURIMatcher.match(uri);
    switch (uriType) {
    case DBAllEntries:
        //no filter or WHERE clause
        break;
    case DBSingleEntry:
        //add ROWID filter when selecting individual item
        queryBuilder.appendWhere(AddDBHelper.KEY_ROWID + "="
                + uri.getLastPathSegment());
        break;      
    default:
        throw new IllegalArgumentException("Unknown URI: " + uri);
    }
    SQLiteDatabase sqlDB = mDBP.getWritableDatabase();
    Cursor cursor = queryBuilder.query(sqlDB, projection, selection,
            selectionArgs, null, null, sortOrder);
    // Ensure potential listeners are getting notified
    cursor.setNotificationUri(getContext().getContentResolver(), uri);
    return cursor;
}

update

以下refillData()的呼叫与第一个日期更改一起使用，但不再起作用。重新启动模拟器并再次尝试后，我能够看到2个单独的日期更改的记录，但它不会再次更改数据。

public void showDialogDate() {
    FragmentTransaction ftLogDate = getFragmentManager().beginTransaction();
    fragDate = LogDateDialogFragment.newInstance(this, new LogDateDialogFragmentListener() {
        public void logbookChangedDate(int year, int month, int day) {          
            now.set(Calendar.YEAR, year);
            now.set(Calendar.MONTH, month);
            now.set(Calendar.DAY_OF_MONTH, day);
            newD = now.getTime();
            SimpleDateFormat newDFormatter = new SimpleDateFormat("dd MMM yyyy");
            strDate = newDFormatter.format(newD);
            btn_logbook_date.setText(strDate);
            refillData();
        }}, now);
    fragDate.show(ftLogDate, "DateDialogFragment");     
}

使用以下呼叫，更改日期后数据不会更改，但是当我按按钮再次打开datepicker时，我可以在后台（在对话框片段）更新中看到ListView。例如，我选择日期2，数据不会更改。我打开datepicker，并在对话框后面显示2个数据显示。我将datepicker设置为日期3，但ListView仍显示日期2的数据。如果再次打开datepicker，则日期3的数据在对话框片段后面的背景中加载。

如果在FragDate.show(...)行之后或FragmentTransaction ftLogDate...行之前致电refillData()，我会得到相同的结果。

public void showDialogDate() {
    FragmentTransaction ftLogDate = getFragmentManager().beginTransaction();
    fragDate = LogDateDialogFragment.newInstance(this, new LogDateDialogFragmentListener() {
        public void logbookChangedDate(int year, int month, int day) {          
            now.set(Calendar.YEAR, year);
            now.set(Calendar.MONTH, month);
            now.set(Calendar.DAY_OF_MONTH, day);
            newD = now.getTime();
            SimpleDateFormat newDFormatter = new SimpleDateFormat("dd MMM yyyy");
            strDate = newDFormatter.format(newD);
            btn_logbook_date.setText(strDate);              
        }}, now);
    refillData();
    fragDate.show(ftLogDate, "DateDialogFragment");     
}

Answer 1

让FuncLogbook活动实现日期集事件的侦听器， LogDateDialogFragmentListener：

public class FuncLogbook extends ListActivity implements
LoaderManager.LoaderCallbacks<Cursor>, OnItemClickListener, LogDateDialogFragmentListener {
//...

然后您需要在活动中实现logbookChangedDate：

@Override
public void logbookChangedDate(int year, int month, int day) {          
            now.set(Calendar.YEAR, year);
            now.set(Calendar.MONTH, month);
            now.set(Calendar.DAY_OF_MONTH, day);
            newD = now.getTime();
            SimpleDateFormat newDFormatter = new SimpleDateFormat("dd MMM yyyy");
            strDate = newDFormatter.format(newD);
            btn_logbook_date.setText(strDate);
            refillData();
}

显示对话框的方法是：

public void showDialogDate() {
    FragmentTransaction ftLogDate = getFragmentManager().beginTransaction();
    fragDate = LogDateDialogFragment.newInstance(this, now);
    fragDate.show(ftLogDate, "DateDialogFragment");     
}

然后，您可以在onAttach回调中的LogDateDialogFragment或其他设置器方法中注册活动。