internal virtual void changeCursor(android.database.Cursor cursor, bool releaseCursors
)
{
if (cursor == this.mCursor)
{
return;
}
this.deactivate();
this.mCursor = cursor;
if (cursor != null)
{
cursor.registerContentObserver(this.mContentObserver);
cursor.registerDataSetObserver(this.mDataSetObserver);
this.mRowIDColumn = cursor.getColumnIndex("_id");
this.mDataValid = true;
// notify the observers about the new cursor
this._enclosing.notifyDataSetChanged(releaseCursors);
}
else
{
this.mRowIDColumn = -1;
this.mDataValid = false;
// notify the observers about the lack of a data set
this._enclosing.notifyDataSetInvalidated();
}
}
/// <summary>Swap in a new Cursor, returning the old Cursor.</summary>
/// <remarks>
/// Swap in a new Cursor, returning the old Cursor. Unlike
/// <see cref="changeCursor(android.database.Cursor)">changeCursor(android.database.Cursor)
/// </see>
/// , the returned old Cursor is <em>not</em>
/// closed.
/// </remarks>
/// <param name="newCursor">The new cursor to be used.</param>
/// <returns>
/// Returns the previously set Cursor, or null if there wasa not one.
/// If the given new Cursor is the same instance is the previously set
/// Cursor, null is also returned.
/// </returns>
public virtual android.database.Cursor swapCursor(android.database.Cursor newCursor
)
{
if (newCursor == mCursor)
{
return(null);
}
android.database.Cursor oldCursor = mCursor;
if (oldCursor != null)
{
if (mChangeObserver != null)
{
oldCursor.unregisterContentObserver(mChangeObserver);
}
if (mDataSetObserver != null)
{
oldCursor.unregisterDataSetObserver(mDataSetObserver);
}
}
mCursor = newCursor;
if (newCursor != null)
{
if (mChangeObserver != null)
{
newCursor.registerContentObserver(mChangeObserver);
}
if (mDataSetObserver != null)
{
newCursor.registerDataSetObserver(mDataSetObserver);
}
mRowIDColumn = newCursor.getColumnIndexOrThrow("_id");
mDataValid = true;
// notify the observers about the new cursor
notifyDataSetChanged();
}
else
{
mRowIDColumn = -1;
mDataValid = false;
// notify the observers about the lack of a data set
notifyDataSetInvalidated();
}
return(oldCursor);
}
internal MyCursorHelper(CursorTreeAdapter _enclosing, android.database.Cursor cursor
)
{
this._enclosing = _enclosing;
bool cursorPresent = cursor != null;
this.mCursor = cursor;
this.mDataValid = cursorPresent;
this.mRowIDColumn = cursorPresent ? cursor.getColumnIndex("_id") : -1;
this.mContentObserver = new android.widget.CursorTreeAdapter.MyCursorHelper.MyContentObserver
(this);
this.mDataSetObserver = new android.widget.CursorTreeAdapter.MyCursorHelper.MyDataSetObserver
(this);
if (cursorPresent)
{
cursor.registerContentObserver(this.mContentObserver);
cursor.registerDataSetObserver(this.mDataSetObserver);
}
}
internal virtual void init(android.content.Context context, android.database.Cursor
c, int flags)
{
if ((flags & FLAG_AUTO_REQUERY) == FLAG_AUTO_REQUERY)
{
flags |= FLAG_REGISTER_CONTENT_OBSERVER;
mAutoRequery = true;
}
else
{
mAutoRequery = false;
}
bool cursorPresent = c != null;
mCursor = c;
mDataValid = cursorPresent;
mContext = context;
mRowIDColumn = cursorPresent ? c.getColumnIndexOrThrow("_id") : -1;
if ((flags & FLAG_REGISTER_CONTENT_OBSERVER) == FLAG_REGISTER_CONTENT_OBSERVER)
{
mChangeObserver = new android.widget.CursorAdapter.ChangeObserver(this);
mDataSetObserver = new android.widget.CursorAdapter.MyDataSetObserver(this);
}
else
{
mChangeObserver = null;
mDataSetObserver = null;
}
if (cursorPresent)
{
if (mChangeObserver != null)
{
c.registerContentObserver(mChangeObserver);
}
if (mDataSetObserver != null)
{
c.registerDataSetObserver(mDataSetObserver);
}
}
}
