Reference:Android.database.MergeCursor

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android.database
public class android.database.MergeCursor

java.lang.Object
	android.database.AbstractCursor		Cursor
		android.database.MergeCursor

A convience class that lets you present an array of Cursors as a single linear Cursor. The schema of the cursors presented is entirely up to the creator of the MergeCursor, and may be different if that is desired. Calls to getColumns, getColumnIndex, etc will return the value for the row that the MergeCursor is currently pointing at.

Contents 1 Summary 1.1 Fields inherited from class android.database.AbstractCursor 1.2 Public Constructors 1.3 Public Methods 1.4 Protected Methods 1.4.1 Methods inherited from class android.database.AbstractCursor 1.4.2 Methods inherited from class java.lang.Object 1.4.3 Methods inherited from interface android.database.Cursor 2 Details 2.1 Public Constructors 2.1.1 public MergeCursor(Cursor[ ] cursors) 2.2 Public Methods 2.2.1 public int count() 2.2.2 public void deactivate() 2.2.3 public boolean deleteRow() 2.2.4 public String[ ]getColumnNames() 2.2.5 public double getDouble(int column) 2.2.6 public float getFloat(int column) 2.2.7 public int getInt(int column) 2.2.8 public long getLong(int column) 2.2.9 public short getShort(int column) 2.2.10 public String getString(int column) 2.2.11 public boolean isNull(int column) 2.2.12 public void registerContentObserver(ContentObserver observer) 2.2.13 public boolean requery() 2.2.14 public void unregisterContentObserver(ContentObserver observer) 2.3 Protected Methods 2.3.1 protected boolean onMove(int oldPosition, int newPosition) 3 References

[edit] Summary

[edit] Fields inherited from class android.database.AbstractCursor

mContentResolver, mCurrentRowID, mPos, mRowIdColumnIndex, mUpdatedRows

[edit] Public Constructors

MergeCursor (Cursor[ ] cursors)

[edit] Public Methods

				int	count ()
					Returns the numbers of rows in the cursor.
				void	deactivate ()
					Deactivates the Cursor, making all calls on it fail until requery() is called.
				boolean	deleteRow ()
					Removes the row at the current cursor position from the underlying data store.
				String[ ]	getColumnNames ()
					Returns a string array holding the names of all of the columns in the result set in the order in which they were listed in the result.
				double	getDouble (int column)
					Returns the value of the requested column as a double.
				float	getFloat (int column)
					Returns the value of the requested column as a float.
				int	getInt (int column)
					Returns the value of the requested column as an int.
				long	getLong (int column)
					Returns the value of the requested column as a long.
				short	getShort (int column)
					Returns the value of the requested column as a short.
				String	getString (int column)
					Returns the value of the requested column as a String.
				boolean	isNull (int column)
					Returns true if the value in the indicated column is null.
				void	registerContentObserver (ContentObserver observer)
					Register an observer that is called when changes happen to the content backing this cursor.
				boolean	requery ()
					Performs the query that created the cursor again, refreshing its contents.
				void	unregisterContentObserver (ContentObserver observer)
					Unregister an observer that has previously been registered with this cursor via registerContentObserver(ContentObserver).

[edit] Protected Methods

				boolean	onMove (int oldPosition, int newPosition)
					This function is called every time the cursor is successfully scrolled to a new position, giving the subclass a chance to update any state it may have.

[edit] Methods inherited from class android.database.AbstractCursor

abortUpdates, checkPosition, close, >)">commitUpdates, commitUpdates, count, deactivate, deleteRow, finalize, first, getColumnIndex, getColumnName, getColumnNames, getDouble, getExtras, getFloat, getInt, getLong, getShort, getString, getUpdatedField, getWantsAllOnMoveCalls, hasUpdates, isAfterLast, isBeforeFirst, isFieldUpdated, isFirst, isLast, isNull, last, move, moveTo, next, onChange, onMove, position, prev, registerContentObserver, registerDataSetObserver, requery, respond, setNotificationUri, supportsUpdates, unregisterContentObserver, unregisterDataSetObserver, update, updateDouble, updateFloat, updateInt, updateLong, updateShort, updateString, updateToNull

[edit] Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

[edit] Methods inherited from interface android.database.Cursor

abortUpdates, close, >)">commitUpdates, commitUpdates, count, deactivate, deleteRow, first, getColumnIndex, getColumnName, getColumnNames, getDouble, getExtras, getFloat, getInt, getLong, getShort, getString, getWantsAllOnMoveCalls, hasUpdates, isAfterLast, isBeforeFirst, isFirst, isLast, isNull, last, move, moveTo, next, position, prev, registerContentObserver, registerDataSetObserver, requery, respond, setNotificationUri, supportsUpdates, unregisterContentObserver, unregisterDataSetObserver, updateDouble, updateFloat, updateInt, updateLong, updateShort, updateString, updateToNull

[edit] Details

[edit] Public Constructors

[edit] public MergeCursor(Cursor[ ] cursors)

[edit] Public Methods

[edit] public int count()

Returns the numbers of rows in the cursor.

[edit] public void deactivate()

Deactivates the Cursor, making all calls on it fail until requery() is called. Inactive Cursors use fewer resources than active Cursors. Calling requery() will make the cursor active again.

[edit] public boolean deleteRow()

Removes the row at the current cursor position from the underlying data store. After this method returns the cursor will be pointing to the row after the row that is deleted. This has the side effect of decrementing the result of count() by one.

[edit] public String[ ]getColumnNames()

Returns a string array holding the names of all of the columns in the result set in the order in which they were listed in the result.

[edit] public double getDouble(int column)

Returns the value of the requested column as a double.

If the native content of that column is not numeric the result will be the result of passing the column value to Double.valueOf(x).

[edit] public float getFloat(int column)

Returns the value of the requested column as a float.

If the native content of that column is not numeric the result will be the result of passing the column value to Float.valueOf(x).

[edit] public int getInt(int column)

Returns the value of the requested column as an int.

If the native content of that column is not numeric the result will be the result of passing the column value to Integer.valueOf(x).

[edit] public long getLong(int column)

Returns the value of the requested column as a long.

If the native content of that column is not numeric the result will be the result of passing the column value to Long.valueOf(x).

[edit] public short getShort(int column)

Returns the value of the requested column as a short.

If the native content of that column is not numeric the result will be the result of passing the column value to Short.valueOf(x).

[edit] public String getString(int column)

Returns the value of the requested column as a String.

If the native content of that column is not text the result will be the result of passing the column value to String.valueOf(x).

[edit] public boolean isNull(int column)

Returns true if the value in the indicated column is null.

[edit] public void registerContentObserver(ContentObserver observer)

Register an observer that is called when changes happen to the content backing this cursor. Typically the data set won't change until requery() is called.

[edit] public boolean requery()

Performs the query that created the cursor again, refreshing its contents. This may be done at any time, including after a call to deactivate().

[edit] public void unregisterContentObserver(ContentObserver observer)

Unregister an observer that has previously been registered with this cursor via registerContentObserver(ContentObserver).

[edit] Protected Methods

[edit] protected boolean onMove(int oldPosition, int newPosition)

This function is called every time the cursor is successfully scrolled to a new position, giving the subclass a chance to update any state it may have. If it returns false the move function will also do so and the cursor will scroll to the beforeFirst position.

Parameters

oldPosition	the position that we're moving from
newPosition	the position that we're moving to

[edit] References

• Original documentation page for Android SDK build m5-rc15e - 14 apr 2008 17:27