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Added in API level 1

public class

MergeCursor

extends AbstractCursor

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

Class Overview

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.

Summary

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Inherited Constants

From interface android.database.Cursor

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Inherited Fields

From class android.database.AbstractCursor

protected boolean	mClosed
protected ContentResolver	mContentResolver
protected Long	mCurrentRowID	This field was deprecated in API level 16. This field should not be used.
protected int	mPos
protected int	mRowIdColumnIndex	This field was deprecated in API level 16. This field should not be used.
protected HashMap < Long , Map < String , Object >>	mUpdatedRows	This field was deprecated in API level 11. This is never updated by this class and should not be used

Public Constructors
	MergeCursor ( Cursor[] cursors)

Public Methods
void	close () Closes the Cursor, releasing all of its resources and making it completely invalid.
void	deactivate () Deactivates the Cursor, making all calls on it fail until `requery()` is called.
byte[]	getBlob (int column) Returns the value of the requested column as a byte array.
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.
int	getCount () Returns the numbers of rows in the cursor.
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.
int	getType (int column) Returns data type of the given column's value.
boolean	isNull (int column) Returns `true` if the value in the indicated column is null.
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.
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.
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)` .

[Expand]

Inherited Methods

From class android.database.AbstractCursor

void	checkPosition () This function throws CursorIndexOutOfBoundsException if the cursor position is out of bounds.
void	close () Closes the Cursor, releasing all of its resources and making it completely invalid.
void	copyStringToBuffer (int columnIndex, CharArrayBuffer buffer) Retrieves the requested column text and stores it in the buffer provided.
void	deactivate () Deactivates the Cursor, making all calls on it fail until `requery()` is called.
void	fillWindow (int position, CursorWindow window) Copies cursor data into the window.
void	finalize () Invoked when the garbage collector has detected that this instance is no longer reachable.
byte[]	getBlob (int column) Returns the value of the requested column as a byte array.
int	getColumnCount () Return total number of columns
int	getColumnIndex ( String columnName) Returns the zero-based index for the given column name, or -1 if the column doesn't exist.
int	getColumnIndexOrThrow ( String columnName) Returns the zero-based index for the given column name, or throws `IllegalArgumentException` if the column doesn't exist.
String	getColumnName (int columnIndex) Returns the column name at the given zero-based column index.
abstract 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.
abstract int	getCount () Returns the numbers of rows in the cursor.
abstract double	getDouble (int column) Returns the value of the requested column as a double.
Bundle	getExtras () Returns a bundle of extra values.
abstract float	getFloat (int column) Returns the value of the requested column as a float.
abstract int	getInt (int column) Returns the value of the requested column as an int.
abstract long	getLong (int column) Returns the value of the requested column as a long.
Uri	getNotificationUri () Return the URI at which notifications of changes in this Cursor's data will be delivered, as previously set by `setNotificationUri(ContentResolver, Uri)` .
final int	getPosition () Returns the current position of the cursor in the row set.
abstract short	getShort (int column) Returns the value of the requested column as a short.
abstract String	getString (int column) Returns the value of the requested column as a String.
int	getType (int column) Returns data type of the given column's value.
Object	getUpdatedField (int columnIndex) This method was deprecated in API level 11. Always returns null since Cursors do not support updating rows
boolean	getWantsAllOnMoveCalls () onMove() will only be called across processes if this method returns true.
CursorWindow	getWindow () If the cursor is backed by a `CursorWindow` , returns a pre-filled window with the contents of the cursor, otherwise null.
final boolean	isAfterLast () Returns whether the cursor is pointing to the position after the last row.
final boolean	isBeforeFirst () Returns whether the cursor is pointing to the position before the first row.
boolean	isClosed () return true if the cursor is closed
boolean	isFieldUpdated (int columnIndex) This method was deprecated in API level 11. Always returns false since Cursors do not support updating rows
final boolean	isFirst () Returns whether the cursor is pointing to the first row.
final boolean	isLast () Returns whether the cursor is pointing to the last row.
abstract boolean	isNull (int column) Returns `true` if the value in the indicated column is null.
final boolean	move (int offset) Move the cursor by a relative amount, forward or backward, from the current position.
final boolean	moveToFirst () Move the cursor to the first row.
final boolean	moveToLast () Move the cursor to the last row.
final boolean	moveToNext () Move the cursor to the next row.
final boolean	moveToPosition (int position) Move the cursor to an absolute position.
final boolean	moveToPrevious () Move the cursor to the previous row.
void	onChange (boolean selfChange) Subclasses must call this method when they finish committing updates to notify all observers.
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.
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 notifyUri) Specifies a content URI to watch for changes.
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)` .

From class java.lang.Object

Object	clone () Creates and returns a copy of this `Object` .
boolean	equals ( Object o) Compares this instance with the specified object and indicates if they are equal.
void	finalize () Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class <?>	getClass () Returns the unique instance of `Class` that represents this object's class.
int	hashCode () Returns an integer hash code for this object.
final void	notify () Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
final void	notifyAll () Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
String	toString () Returns a string containing a concise, human-readable description of this object.
final void	wait () Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object.
final void	wait (long millis, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait (long millis) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.

From interface android.database.CrossProcessCursor

From interface android.database.Cursor

abstract void	close () Closes the Cursor, releasing all of its resources and making it completely invalid.
abstract void	copyStringToBuffer (int columnIndex, CharArrayBuffer buffer) Retrieves the requested column text and stores it in the buffer provided.
abstract void	deactivate () This method was deprecated in API level 16. Since `requery()` is deprecated, so too is this.
abstract byte[]	getBlob (int columnIndex) Returns the value of the requested column as a byte array.
abstract int	getColumnCount () Return total number of columns
abstract int	getColumnIndex ( String columnName) Returns the zero-based index for the given column name, or -1 if the column doesn't exist.
abstract int	getColumnIndexOrThrow ( String columnName) Returns the zero-based index for the given column name, or throws `IllegalArgumentException` if the column doesn't exist.
abstract String	getColumnName (int columnIndex) Returns the column name at the given zero-based column index.
abstract 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.
abstract int	getCount () Returns the numbers of rows in the cursor.
abstract double	getDouble (int columnIndex) Returns the value of the requested column as a double.
abstract Bundle	getExtras () Returns a bundle of extra values.
abstract float	getFloat (int columnIndex) Returns the value of the requested column as a float.
abstract int	getInt (int columnIndex) Returns the value of the requested column as an int.
abstract long	getLong (int columnIndex) Returns the value of the requested column as a long.
abstract Uri	getNotificationUri () Return the URI at which notifications of changes in this Cursor's data will be delivered, as previously set by `setNotificationUri(ContentResolver, Uri)` .
abstract int	getPosition () Returns the current position of the cursor in the row set.
abstract short	getShort (int columnIndex) Returns the value of the requested column as a short.
abstract String	getString (int columnIndex) Returns the value of the requested column as a String.
abstract int	getType (int columnIndex) Returns data type of the given column's value.
abstract boolean	getWantsAllOnMoveCalls () onMove() will only be called across processes if this method returns true.
abstract boolean	isAfterLast () Returns whether the cursor is pointing to the position after the last row.
abstract boolean	isBeforeFirst () Returns whether the cursor is pointing to the position before the first row.
abstract boolean	isClosed () return true if the cursor is closed
abstract boolean	isFirst () Returns whether the cursor is pointing to the first row.
abstract boolean	isLast () Returns whether the cursor is pointing to the last row.
abstract boolean	isNull (int columnIndex) Returns `true` if the value in the indicated column is null.
abstract boolean	move (int offset) Move the cursor by a relative amount, forward or backward, from the current position.
abstract boolean	moveToFirst () Move the cursor to the first row.
abstract boolean	moveToLast () Move the cursor to the last row.
abstract boolean	moveToNext () Move the cursor to the next row.
abstract boolean	moveToPosition (int position) Move the cursor to an absolute position.
abstract boolean	moveToPrevious () Move the cursor to the previous row.
abstract void	registerContentObserver ( ContentObserver observer) Register an observer that is called when changes happen to the content backing this cursor.
abstract 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()` .
abstract boolean	requery () This method was deprecated in API level 11. Don't use this. Just request a new cursor, so you can do this asynchronously and update your list view once the new cursor comes back.
abstract Bundle	respond ( Bundle extras) This is an out-of-band way for the the user of a cursor to communicate with the cursor.
abstract void	setNotificationUri ( ContentResolver cr, Uri uri) Register to watch a content URI for changes.
abstract void	unregisterContentObserver ( ContentObserver observer) Unregister an observer that has previously been registered with this cursor via `registerContentObserver(ContentObserver)` .
abstract void	unregisterDataSetObserver ( DataSetObserver observer) Unregister an observer that has previously been registered with this cursor via `registerContentObserver(ContentObserver)` .

From interface java.io.Closeable

From interface java.lang.AutoCloseable

Public Constructors

public MergeCursor ( Cursor[] cursors)

Added in API level 1

Public Methods

public void close ()

Added in API level 1

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.

public void deactivate ()

Added in API level 1

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.

public byte[] getBlob (int column)

Added in API level 1

Returns the value of the requested column as a byte array.

The result and whether this method throws an exception when the column value is null or the column type is not a blob type is implementation-defined.

Parameters

column	the zero-based index of the target column.

Returns

the value of that column as a byte array.

public String[] getColumnNames ()

Added in API level 1

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.

public int getCount ()

Added in API level 1

Returns the numbers of rows in the cursor.

Returns

the number of rows in the cursor.

public double getDouble (int column)

Added in API level 1

Returns the value of the requested column as a double.

The result and whether this method throws an exception when the column value is null, the column type is not a floating-point type, or the floating-point value is not representable as a double value is implementation-defined.

Parameters

column	the zero-based index of the target column.

Returns

the value of that column as a double.

public float getFloat (int column)

Added in API level 1

Returns the value of the requested column as a float.

Parameters

column	the zero-based index of the target column.

Returns

the value of that column as a float.

public int getInt (int column)

Added in API level 1

Returns the value of the requested column as an int.

The result and whether this method throws an exception when the column value is null, the column type is not an integral type, or the integer value is outside the range [ Integer.MIN_VALUE , Integer.MAX_VALUE ] is implementation-defined.

Parameters

column	the zero-based index of the target column.

Returns

the value of that column as an int.

public long getLong (int column)

Added in API level 1

Returns the value of the requested column as a long.

The result and whether this method throws an exception when the column value is null, the column type is not an integral type, or the integer value is outside the range [ Long.MIN_VALUE , Long.MAX_VALUE ] is implementation-defined.

Parameters

column	the zero-based index of the target column.

Returns

the value of that column as a long.

public short getShort (int column)

Added in API level 1

Returns the value of the requested column as a short.

The result and whether this method throws an exception when the column value is null, the column type is not an integral type, or the integer value is outside the range [ Short.MIN_VALUE , Short.MAX_VALUE ] is implementation-defined.

Parameters

column	the zero-based index of the target column.

Returns

the value of that column as a short.

public String getString (int column)

Added in API level 1

Returns the value of the requested column as a String.

The result and whether this method throws an exception when the column value is null or the column type is not a string type is implementation-defined.

Parameters

column	the zero-based index of the target column.

Returns

the value of that column as a String.

public int getType (int column)

Added in API level 11

Returns data type of the given column's value. The preferred type of the column is returned but the data may be converted to other types as documented in the get-type methods such as getInt(int) , getFloat(int) etc.

Returned column types are

Parameters

column	the zero-based index of the target column.

Returns

column value type

public boolean isNull (int column)

Added in API level 1

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

Parameters

column	the zero-based index of the target column.

Returns

whether the column value is null.

public boolean onMove (int oldPosition, int newPosition)

Added in API level 1

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

Returns

true if the move is successful, false otherwise

public void registerContentObserver ( ContentObserver observer)

Added in API level 1

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.

public void registerDataSetObserver ( DataSetObserver observer)

Added in API level 1

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.

public boolean requery ()

Added in API level 1

Performs the query that created the cursor again, refreshing its contents. This may be done at any time, including after a call to deactivate() . Since this method could execute a query on the database and potentially take a while, it could cause ANR if it is called on Main (UI) thread. A warning is printed if this method is being executed on Main thread.

Returns

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

public void unregisterContentObserver ( ContentObserver observer)

Added in API level 1

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

Parameters

observer	the object to unregister.

public void unregisterDataSetObserver ( DataSetObserver observer)

Added in API level 1

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

Parameters

observer	the object to unregister.

Results

Interfaces

Classes

Enums

Exceptions

MergeCursor

Class Overview

Summary

Public Constructors

public MergeCursor ( Cursor[] cursors)

Public Methods

public void close ()

public void deactivate ()

public byte[] getBlob (int column)

Parameters

Returns

public String[] getColumnNames ()

Returns

public int getCount ()

Returns

public double getDouble (int column)

Parameters

Returns

public float getFloat (int column)

Parameters

Returns

public int getInt (int column)

Parameters

Returns

public long getLong (int column)

Parameters

Returns

public short getShort (int column)

Parameters

Returns

public String getString (int column)

Parameters

Returns

public int getType (int column)

Parameters

Returns

public boolean isNull (int column)

Parameters

Returns

public boolean onMove (int oldPosition, int newPosition)

Parameters

Returns

public void registerContentObserver ( ContentObserver observer)

Parameters

public void registerDataSetObserver ( DataSetObserver observer)

Parameters

public boolean requery ()

Returns

public void unregisterContentObserver ( ContentObserver observer)

Parameters

public void unregisterDataSetObserver ( DataSetObserver observer)

Parameters