AbstractWindowedCursor
public abstract class AbstractWindowedCursor
extends AbstractCursor
Known Direct Subclasses
|
A base class for Cursors that store their data in CursorWindow
s.
The cursor owns the cursor window it uses. When the cursor is closed, its window is also closed. Likewise, when the window used by the cursor is changed, its old window is closed. This policy of strict ownership ensures that cursor windows are not leaked.
Subclasses are responsible for filling the cursor window with data during onMove(int, int)
, allocating a new cursor window if necessary. During requery()
, the existing cursor window should be cleared and filled with new data.
If the contents of the cursor change or become invalid, the old window must be closed (because it is owned by the cursor) and set to null.
Summary
Public methods |
void |
copyStringToBuffer(int columnIndex, CharArrayBuffer buffer) Retrieves the requested column text and stores it in the buffer provided. |
byte[] |
getBlob(int columnIndex) Returns the value of the requested column as a byte array. |
double |
getDouble(int columnIndex) Returns the value of the requested column as a double. |
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. |
int |
getType(int columnIndex) Returns data type of the given column's value. |
CursorWindow |
getWindow() If the cursor is backed by a CursorWindow , returns a pre-filled window with the contents of the cursor, otherwise null. |
boolean |
hasWindow() Returns true if the cursor has an associated cursor window. |
boolean |
isBlob(int columnIndex) This method was deprecated in API level 11. Use getType(int) |
boolean |
isFloat(int columnIndex) This method was deprecated in API level 11. Use getType(int) |
boolean |
isLong(int columnIndex) This method was deprecated in API level 11. Use getType(int) |
boolean |
isNull(int columnIndex) Returns true if the value in the indicated column is null. |
boolean |
isString(int columnIndex) This method was deprecated in API level 11. Use getType(int) |
void |
setWindow(CursorWindow window) Sets a new cursor window for the cursor to use. |
Protected methods |
void |
checkPosition() This function throws CursorIndexOutOfBoundsException if the cursor position is out of bounds. |
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() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. |
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 |
setExtras(Bundle extras) Sets a Bundle that will be returned by getExtras() . |
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) . |
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From class java.lang.Object
Object |
clone() Creates and returns a copy of this object. |
boolean |
equals(Object obj) Indicates whether some other object is "equal to" this one. |
void |
finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. |
final Class<?> |
getClass() Returns the runtime class of this Object . |
int |
hashCode() Returns a hash code value for the object. |
final void |
notify() Wakes up a single thread that is waiting on this object's monitor. |
final void |
notifyAll() Wakes up all threads that are waiting on this object's monitor. |
String |
toString() Returns a string representation of the object. |
final void |
wait(long millis, int nanos) Causes the current thread to wait until another thread invokes the notify() method or the notifyAll() method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed. |
final void |
wait(long millis) Causes the current thread to wait until either another thread invokes the notify() method or the notifyAll() method for this object, or a specified amount of time has elapsed. |
final void |
wait() Causes the current thread to wait until another thread invokes the notify() method or the notifyAll() method for this object. |
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From interface android.database.CrossProcessCursor
abstract void |
fillWindow(int position, CursorWindow window) Copies cursor data into the window. |
abstract CursorWindow |
getWindow() Returns a pre-filled window that contains the data within this cursor. |
abstract 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. |
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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 |
setExtras(Bundle extras) Sets a Bundle that will be returned by getExtras() . |
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) . |
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From interface java.io.Closeable
abstract void |
close() Closes this stream and releases any system resources associated with it. |
|
From interface java.lang.AutoCloseable
abstract void |
close() Closes this resource, relinquishing any underlying resources. |
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Fields
mWindow
CursorWindow mWindow
The cursor window owned by this cursor.
Public constructors
AbstractWindowedCursor
AbstractWindowedCursor ()
Public methods
copyStringToBuffer
void copyStringToBuffer (int columnIndex,
CharArrayBuffer buffer)
Retrieves the requested column text and stores it in the buffer provided. If the buffer size is not sufficient, a new char buffer will be allocated and assigned to CharArrayBuffer.data
Parameters |
columnIndex |
int : the zero-based index of the target column. if the target column is null, return buffer |
buffer |
CharArrayBuffer : the buffer to copy the text into. |
getBlob
byte[] getBlob (int columnIndex)
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 |
columnIndex |
int : the zero-based index of the target column. |
Returns |
byte[] |
the value of that column as a byte array. |
getDouble
double getDouble (int columnIndex)
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 |
columnIndex |
int : the zero-based index of the target column. |
Returns |
double |
the value of that column as a double. |
getFloat
float getFloat (int columnIndex)
Returns the value of the requested column as a float.
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 float
value is implementation-defined.
Parameters |
columnIndex |
int : the zero-based index of the target column. |
Returns |
float |
the value of that column as a float. |
getInt
int getInt (int columnIndex)
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 |
columnIndex |
int : the zero-based index of the target column. |
Returns |
int |
the value of that column as an int. |
getLong
long getLong (int columnIndex)
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 |
columnIndex |
int : the zero-based index of the target column. |
Returns |
long |
the value of that column as a long. |
getShort
short getShort (int columnIndex)
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 |
columnIndex |
int : the zero-based index of the target column. |
Returns |
short |
the value of that column as a short. |
getString
String getString (int columnIndex)
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 |
columnIndex |
int : the zero-based index of the target column. |
Returns |
String |
the value of that column as a String. |
getType
int getType (int columnIndex)
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 |
columnIndex |
int : the zero-based index of the target column. |
Returns |
int |
column value type |
getWindow
CursorWindow getWindow ()
If the cursor is backed by a CursorWindow
, returns a pre-filled window with the contents of the cursor, otherwise null.
Returns |
CursorWindow |
The pre-filled window that backs this cursor, or null if none. |
hasWindow
boolean hasWindow ()
Returns true if the cursor has an associated cursor window.
Returns |
boolean |
True if the cursor has an associated cursor window. |
isBlob
boolean isBlob (int columnIndex)
This method was deprecated in API level 11.
Use getType(int)
Parameters |
columnIndex |
int
|
isFloat
boolean isFloat (int columnIndex)
This method was deprecated in API level 11.
Use getType(int)
Parameters |
columnIndex |
int
|
isLong
boolean isLong (int columnIndex)
This method was deprecated in API level 11.
Use getType(int)
Parameters |
columnIndex |
int
|
isNull
boolean isNull (int columnIndex)
Returns true
if the value in the indicated column is null.
Parameters |
columnIndex |
int : the zero-based index of the target column. |
Returns |
boolean |
whether the column value is null. |
isString
boolean isString (int columnIndex)
This method was deprecated in API level 11.
Use getType(int)
Parameters |
columnIndex |
int
|
setWindow
void setWindow (CursorWindow window)
Sets a new cursor window for the cursor to use.
The cursor takes ownership of the provided cursor window; the cursor window will be closed when the cursor is closed or when the cursor adopts a new cursor window.
If the cursor previously had a cursor window, then it is closed when the new cursor window is assigned.
Parameters |
window |
CursorWindow : The new cursor window, typically a remote cursor window. |
Protected methods
checkPosition
void checkPosition ()
This function throws CursorIndexOutOfBoundsException if the cursor position is out of bounds. Subclass implementations of the get functions should call this before attempting to retrieve data.