Reference:Android.database.Cursor

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android.database
public interface android.database.Cursor

android.database.Cursor

This interface provides random read-write access to the result set returned by a database query.

[edit] Known Indirect Subclasses

AbstractCursor, AbstractWindowedCursor, ArrayListCursor, DatabaseContentProvider.DcpCursor, MergeCursor, SQLiteCursor

[edit] Summary

[edit] Public Methods

				void	abortUpdates ()
					Reverts all updates made to the cursor since the last call to commitUpdates.
				void	close ()
					Closes the Cursor, releasing all of its resources and making it completely invalid.
				boolean	>)">commitUpdates (Map values)
					Atomically commits all updates to the backing store, as well as the updates included in values.
				boolean	commitUpdates ()
					Atomically commits all updates to the backing store.
				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.
				boolean	first ()
					Move the cursor to the first row.
				int	getColumnIndex (String columnName)
					Returns the zero-based index for the given column name.
				String	getColumnName (int columnIndex)
					Returns the column name at the given zero-based column index.
				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 columnIndex)
					Returns the value of the requested column as a double.
				Bundle	getExtras ()
					Returns a bundle of extra values.
				float	getFloat (int columnIndex)
					Returns the value of the requested column as a float.
				int	getInt (int columnIndex)
					Returns the value of the requested column as an int.
				long	getLong (int columnIndex)
					Returns the value of the requested column as a long.
				short	getShort (int columnIndex)
					Returns the value of the requested column as a short.
				String	getString (int columnIndex)
					Returns the value of the requested column as a String.
				boolean	getWantsAllOnMoveCalls ()
					onMove() will only be called across processes if this method returns true.
				boolean	hasUpdates ()
					Returns `true` if there are pending updates that have not yet been committed.
				boolean	isAfterLast ()
					Returns whether the cursor is pointing to the position after the last row.
				boolean	isBeforeFirst ()
					Returns whether the cursor is pointing to the position before the first row.
				boolean	isFirst ()
					Returns whether the cursor is pointing to the first row.
				boolean	isLast ()
					Returns whether the cursor is pointing to the last row.
				boolean	isNull (int columnIndex)
					Returns `true` if the value in the indicated column is null.
				boolean	last ()
					Move the cursor to the last row.
				boolean	move (int offset)
					Move the cursor by a relative amount, forward or backward, from the current position.
				boolean	moveTo (int position)
					Move the cursor to an absolute position.
				boolean	next ()
					Move the cursor to the next row.
				int	position ()
					Returns the current position of the cursor in the row set.
				boolean	prev ()
					Move the cursor to the previous row.
				void	registerContentObserver (ContentObserver observer)
					Register an observer that is called when changes happen to the content backing this cursor.
				void	registerDataSetObserver (DataSetObserver observer)
					Register an observer that is called when changes happen to the contents of the this cursors data set, for example, when the data set is changed via requery(), deactivate(), or close().
				boolean	requery ()
					Performs the query that created the cursor again, refreshing its contents.
				Bundle	respond (Bundle extras)
					This is an out-of-band way for the the user of a cursor to communicate with the cursor.
				void	setNotificationUri (ContentResolver cr, Uri uri)
					Register to watch a content URI for changes.
				boolean	supportsUpdates ()
					Returns `true` if the cursor supports updates.
				void	unregisterContentObserver (ContentObserver observer)
					Unregister an observer that has previously been registered with this cursor via registerContentObserver(ContentObserver).
				void	unregisterDataSetObserver (DataSetObserver observer)
					Unregister an observer that has previously been registered with this cursor via registerContentObserver(ContentObserver).
				boolean	updateDouble (int columnIndex, double value)
					Updates the value for the given column in the row the cursor is currently pointing at.
				boolean	updateFloat (int columnIndex, float value)
					Updates the value for the given column in the row the cursor is currently pointing at.
				boolean	updateInt (int columnIndex, int value)
					Updates the value for the given column in the row the cursor is currently pointing at.
				boolean	updateLong (int columnIndex, long value)
					Updates the value for the given column in the row the cursor is currently pointing at.
				boolean	updateShort (int columnIndex, short value)
					Updates the value for the given column in the row the cursor is currently pointing at.
				boolean	updateString (int columnIndex, String value)
					Updates the value for the given column in the row the cursor is currently pointing at.
				boolean	updateToNull (int columnIndex)
					Removes the value for the given column in the row the cursor is currently pointing at.

[edit] Details

[edit] Public Methods

[edit] public void abortUpdates()

Reverts all updates made to the cursor since the last call to commitUpdates.

[edit] public void close()

Closes the Cursor, releasing all of its resources and making it completely invalid. Unlike deactivate() a call to requery() will not make the Cursor valid again.

[edit] public boolean commitUpdates(Map values)

Atomically commits all updates to the backing store, as well as the updates included in values. After completion, this method leaves the data in an inconsistent state and you should call requery() before reading data from the cursor again.

Parameters

values	A map from row IDs to Maps associating column names with updated values. A null value indicates the field should be removed.

Returns

whether the operation succeeded.

[edit] public boolean commitUpdates()

Atomically commits all updates to the backing store. After completion, this method leaves the data in an inconsistent state and you should call requery() before reading data from the cursor again.

Returns

whether the operation succeeded.

[edit] public int count()

Returns the numbers of rows in the cursor.

Returns

the number 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.

Returns

whether the record was successfully deleted.

[edit] public boolean first()

Move the cursor to the first row.

This method will return false if the cursor is empty.

Returns

whether the move succeeded.

[edit] public int getColumnIndex(String columnName)

Returns the zero-based index for the given column name.

Parameters

columnName	the name of the target column.

Returns

the zero-based column index for the given column name, or -1 if the column name does not exist.

[edit] public String getColumnName(int columnIndex)

Returns the column name at the given zero-based column index.

Parameters

columnIndex	the zero-based index of the target column.

Returns

the column name for the given column index.

[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.

Returns

the names of the columns returned in this query.

[edit] public double getDouble(int columnIndex)

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).

Parameters

columnIndex	the zero-based index of the target column.

Returns

the value of that column as a double.

[edit] public Bundle getExtras()

Returns a bundle of extra values. This is an optional way for cursors to provide out-of-band metadata to their users. One use of this is for reporting on the progress of network requests that are required to fetch data for the cursor.

These values may only change when requery is called.

Returns

cursor-defined values, or Bundle.EMTPY if there are no values. Never null.

[edit] public float getFloat(int columnIndex)

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).

Parameters

columnIndex	the zero-based index of the target column.

Returns

the value of that column as a float.

[edit] public int getInt(int columnIndex)

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).

Parameters

columnIndex	the zero-based index of the target column.

Returns

the value of that column as an int.

[edit] public long getLong(int columnIndex)

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).

Parameters

columnIndex	the zero-based index of the target column.

Returns

the value of that column as a long.

[edit] public short getShort(int columnIndex)

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).

Parameters

columnIndex	the zero-based index of the target column.

Returns

the value of that column as a short.

[edit] public String getString(int columnIndex)

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).

Parameters

columnIndex	the zero-based index of the target column.

Returns

the value of that column as a String.

[edit] public boolean getWantsAllOnMoveCalls()

onMove() will only be called across processes if this method returns true.

Returns

whether all cursor movement should result in a call to onMove().

[edit] public boolean hasUpdates()

Returns true if there are pending updates that have not yet been committed.

Returns

true if there are pending updates that have not yet been committed.

[edit] public boolean isAfterLast()

Returns whether the cursor is pointing to the position after the last row.

Returns

whether the cursor is after the last result.

[edit] public boolean isBeforeFirst()

Returns whether the cursor is pointing to the position before the first row.

Returns

whether the cursor is before the first result.

[edit] public boolean isFirst()

Returns whether the cursor is pointing to the first row.

Returns

whether the cursor is pointing at the first entry.

[edit] public boolean isLast()

Returns whether the cursor is pointing to the last row.

Returns

whether the cursor is pointing at the last entry.

[edit] public boolean isNull(int columnIndex)

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

Parameters

columnIndex	the zero-based index of the target column.

Returns

whether the column value is null.

[edit] public boolean last()

Move the cursor to the last row.

This method will return false if the cursor is empty.

Returns

whether the move succeeded.

[edit] public boolean move(int offset)

Move the cursor by a relative amount, forward or backward, from the current position. Positive offsets move forwards, negative offsets move backwards. If the final position is outside of the bounds of the result set then the resultant position will be pinned to -1 or count() depending on whether the value is off the front or end of the set, respectively.

This method will return true if the requested destination was reachable, otherwise, it returns false. For example, if the cursor is at currently on the second entry in the result set and move(-5) is called, the position will be pinned at -1, and false will be returned.

Parameters

offset	the offset to be applied from the current position.

Returns

whether the requested move fully succeeded.

[edit] public boolean moveTo(int position)

Move the cursor to an absolute position. The valid range of values is -1 <= position <= count.

This method will return true if the request destination was reachable, otherwise, it returns false.

Parameters

position	the zero-based position to move to.

Returns

whether the requested move fully succeeded.

[edit] public boolean next()

Move the cursor to the next row.

This method will return false if the cursor is already past the last entry in the result set.

Returns

whether the move succeeded.

[edit] public int position()

Returns the current position of the cursor in the row set. The value is zero-based. When the row set is first returned the cursor will be at positon -1, which is before the first row. After the last row is returned another call to next() will leave the cursor past the last entry, at a position of count().

Returns

the current cursor position.

[edit] public boolean prev()

Move the cursor to the previous row.

This method will return false if the cursor is already before the first entry in the result set.

Returns

whether the move succeeded.

[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.

Parameters

observer	the object that gets notified when the content backing the cursor changes.

[edit] public void registerDataSetObserver(DataSetObserver observer)

Register an observer that is called when changes happen to the contents of the this cursors data set, for example, when the data set is changed via requery(), deactivate(), or close().

Parameters

observer	the object that gets notified when the cursors data set changes.

[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().

Returns

true if the requery succeeded, false if not, in which case the cursor becomes invalid.

[edit] public Bundle respond(Bundle extras)

This is an out-of-band way for the the user of a cursor to communicate with the cursor. The structure of each bundle is entirely defined by the cursor.

One use of this is to tell a cursor that it should retry its network request after it reported an error.

Parameters

extras	extra values, or Bundle.EMTPY. Never null.

Returns

extra values, or Bundle.EMTPY. Never null.

[edit] public void setNotificationUri(ContentResolver cr, Uri uri)

Register to watch a content URI for changes. This can be the URI of a specific data row (for example, "content://my_provider_type/23"), or a a generic URI for a content type.

Parameters

cr	The content resolver from the caller's context. The listener attached to this resolver will be notified.
uri	The content URI to watch.

[edit] public boolean supportsUpdates()

Returns true if the cursor supports updates.

Returns

whether the cursor supports updates.

[edit] public void unregisterContentObserver(ContentObserver observer)

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

Parameters

observer	the object to unregister.

[edit] public void unregisterDataSetObserver(DataSetObserver observer)

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