CursorWindow
public
class
CursorWindow
extends SQLiteClosable
implements
Parcelable
java.lang.Object | ||
↳ | android.database.sqlite.SQLiteClosable | |
↳ | android.database.CursorWindow |
A buffer containing multiple cursor rows.
A CursorWindow
is read-write when initially created and used locally.
When sent to a remote process (by writing it to a Parcel
), the remote process
receives a read-only view of the cursor window. Typically the cursor window
will be allocated by the producer, filled with data, and then sent to the
consumer for reading.
Summary
Inherited constants |
---|
Fields | |
---|---|
public
static
final
Creator<CursorWindow> |
CREATOR
|
Public constructors | |
---|---|
CursorWindow(String name)
Creates a new empty cursor window and gives it a name. |
|
CursorWindow(String name, long windowSizeBytes)
Creates a new empty cursor window and gives it a name. |
|
CursorWindow(boolean localWindow)
This constructor is deprecated.
There is no longer a distinction between local and remote
cursor windows. Use the |
Public methods | |
---|---|
boolean
|
allocRow()
Allocates a new row at the end of this cursor window. |
void
|
clear()
Clears out the existing contents of the window, making it safe to reuse for new data. |
void
|
copyStringToBuffer(int row, int column, CharArrayBuffer buffer)
Copies the text of the field at the specified row and column index into
a |
int
|
describeContents()
Describe the kinds of special objects contained in this Parcelable instance's marshaled representation. |
void
|
freeLastRow()
Frees the last row in this cursor window. |
byte[]
|
getBlob(int row, int column)
Gets the value of the field at the specified row and column index as a byte array. |
double
|
getDouble(int row, int column)
Gets the value of the field at the specified row and column index as a
|
float
|
getFloat(int row, int column)
Gets the value of the field at the specified row and column index as a
|
int
|
getInt(int row, int column)
Gets the value of the field at the specified row and column index as an
|
long
|
getLong(int row, int column)
Gets the value of the field at the specified row and column index as a |
int
|
getNumRows()
Gets the number of rows in this window. |
short
|
getShort(int row, int column)
Gets the value of the field at the specified row and column index as a
|
int
|
getStartPosition()
Gets the start position of this cursor window. |
String
|
getString(int row, int column)
Gets the value of the field at the specified row and column index as a string. |
int
|
getType(int row, int column)
Returns the type of the field at the specified row and column index. |
boolean
|
isBlob(int row, int column)
This method was deprecated
in API level 15.
Use |
boolean
|
isFloat(int row, int column)
This method was deprecated
in API level 15.
Use |
boolean
|
isLong(int row, int column)
This method was deprecated
in API level 15.
Use |
boolean
|
isNull(int row, int column)
This method was deprecated
in API level 15.
Use |
boolean
|
isString(int row, int column)
This method was deprecated
in API level 15.
Use |
static
CursorWindow
|
newFromParcel(Parcel p)
|
boolean
|
putBlob(byte[] value, int row, int column)
Copies a byte array into the field at the specified row and column index. |
boolean
|
putDouble(double value, int row, int column)
Puts a double-precision floating point value into the field at the specified row and column index. |
boolean
|
putLong(long value, int row, int column)
Puts a long integer into the field at the specified row and column index. |
boolean
|
putNull(int row, int column)
Puts a null value into the field at the specified row and column index. |
boolean
|
putString(String value, int row, int column)
Copies a string into the field at the specified row and column index. |
boolean
|
setNumColumns(int columnNum)
Sets the number of columns in this window. |
void
|
setStartPosition(int pos)
Sets the start position of this cursor window. |
String
|
toString()
Returns a string representation of the object. |
void
|
writeToParcel(Parcel dest, int flags)
Flatten this object in to a Parcel. |
Protected methods | |
---|---|
void
|
finalize()
Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. |
void
|
onAllReferencesReleased()
Called when the last reference to the object was released by
a call to |
Inherited methods | |
---|---|
Fields
Public constructors
CursorWindow
public CursorWindow (String name)
Creates a new empty cursor window and gives it a name.
The cursor initially has no rows or columns. Call setNumColumns(int)
to
set the number of columns before adding any rows to the cursor.
Parameters | |
---|---|
name |
String : The name of the cursor window, or null if none. |
CursorWindow
public CursorWindow (String name, long windowSizeBytes)
Creates a new empty cursor window and gives it a name.
The cursor initially has no rows or columns. Call setNumColumns(int)
to
set the number of columns before adding any rows to the cursor.
Parameters | |
---|---|
name |
String : The name of the cursor window, or null if none. |
windowSizeBytes |
long : Size of cursor window in bytes.
Value is a non-negative number of bytes. |
Throws | |
---|---|
IllegalArgumentException |
if windowSizeBytes is less than 0 |
AssertionError |
if created window pointer is 0
Note: Memory is dynamically allocated as data rows are added to the window. Depending on the amount of data stored, the actual amount of memory allocated can be lower than specified size, but cannot exceed it. |
CursorWindow
public CursorWindow (boolean localWindow)
This constructor is deprecated.
There is no longer a distinction between local and remote
cursor windows. Use the CursorWindow(java.lang.String)
constructor instead.
Creates a new empty cursor window.
The cursor initially has no rows or columns. Call setNumColumns(int)
to
set the number of columns before adding any rows to the cursor.
Parameters | |
---|---|
localWindow |
boolean : True if this window will be used in this process only,
false if it might be sent to another processes. This argument is ignored. |
Public methods
allocRow
public boolean allocRow ()
Allocates a new row at the end of this cursor window.
Returns | |
---|---|
boolean |
True if successful, false if the cursor window is out of memory. |
clear
public void clear ()
Clears out the existing contents of the window, making it safe to reuse for new data.
The start position (getStartPosition()
), number of rows (getNumRows()
),
and number of columns in the cursor are all reset to zero.
copyStringToBuffer
public void copyStringToBuffer (int row, int column, CharArrayBuffer buffer)
Copies the text of the field at the specified row and column index into
a CharArrayBuffer
.
The buffer is populated as follows:
- If the buffer is too small for the value to be copied, then it is automatically resized.
- If the field is of type
Cursor#FIELD_TYPE_NULL
, then the buffer is set to an empty string. - If the field is of type
Cursor#FIELD_TYPE_STRING
, then the buffer is set to the contents of the string. - If the field is of type
Cursor#FIELD_TYPE_INTEGER
, then the buffer is set to a string representation of the integer in decimal, obtained by formatting the value with theprintf
family of functions using format specifier%lld
. - If the field is of type
Cursor#FIELD_TYPE_FLOAT
, then the buffer is set to a string representation of the floating-point value in decimal, obtained by formatting the value with theprintf
family of functions using format specifier%g
. - If the field is of type
Cursor#FIELD_TYPE_BLOB
, then aSQLiteException
is thrown.
Parameters | |
---|---|
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
buffer |
CharArrayBuffer : The CharArrayBuffer to hold the string. It is automatically
resized if the requested string is larger than the buffer's current capacity. |
describeContents
public int describeContents ()
Describe the kinds of special objects contained in this Parcelable
instance's marshaled representation. For example, if the object will
include a file descriptor in the output of writeToParcel(android.os.Parcel, int)
,
the return value of this method must include the
CONTENTS_FILE_DESCRIPTOR
bit.
Returns | |
---|---|
int |
a bitmask indicating the set of special object types marshaled
by this Parcelable object instance.
Value is either 0 or CONTENTS_FILE_DESCRIPTOR |
freeLastRow
public void freeLastRow ()
Frees the last row in this cursor window.
getBlob
public byte[] getBlob (int row, int column)
Gets the value of the field at the specified row and column index as a byte array.
The result is determined as follows:
- If the field is of type
Cursor#FIELD_TYPE_NULL
, then the result isnull
. - If the field is of type
Cursor#FIELD_TYPE_BLOB
, then the result is the blob value. - If the field is of type
Cursor#FIELD_TYPE_STRING
, then the result is the array of bytes that make up the internal representation of the string value. - If the field is of type
Cursor#FIELD_TYPE_INTEGER
orCursor#FIELD_TYPE_FLOAT
, then aSQLiteException
is thrown.
Parameters | |
---|---|
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
Returns | |
---|---|
byte[] |
The value of the field as a byte array. |
getDouble
public double getDouble (int row, int column)
Gets the value of the field at the specified row and column index as a
double
.
The result is determined as follows:
- If the field is of type
Cursor#FIELD_TYPE_NULL
, then the result is0.0
. - If the field is of type
Cursor#FIELD_TYPE_STRING
, then the result is the value obtained by parsing the string value withstrtod
. - If the field is of type
Cursor#FIELD_TYPE_INTEGER
, then the result is the integer value converted to adouble
. - If the field is of type
Cursor#FIELD_TYPE_FLOAT
, then the result is thedouble
value. - If the field is of type
Cursor#FIELD_TYPE_BLOB
, then aSQLiteException
is thrown.
Parameters | |
---|---|
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
Returns | |
---|---|
double |
The value of the field as a double . |
getFloat
public float getFloat (int row, int column)
Gets the value of the field at the specified row and column index as a
float
.
The result is determined by invoking getDouble(int, int)
and converting the
result to float
.
Parameters | |
---|---|
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
Returns | |
---|---|
float |
The value of the field as an float . |
getInt
public int getInt (int row, int column)
Gets the value of the field at the specified row and column index as an
int
.
The result is determined by invoking getLong(int, int)
and converting the
result to int
.
Parameters | |
---|---|
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
Returns | |
---|---|
int |
The value of the field as an int . |
getLong
public long getLong (int row, int column)
Gets the value of the field at the specified row and column index as a long
.
The result is determined as follows:
- If the field is of type
Cursor#FIELD_TYPE_NULL
, then the result is0L
. - If the field is of type
Cursor#FIELD_TYPE_STRING
, then the result is the value obtained by parsing the string value withstrtoll
. - If the field is of type
Cursor#FIELD_TYPE_INTEGER
, then the result is thelong
value. - If the field is of type
Cursor#FIELD_TYPE_FLOAT
, then the result is the floating-point value converted to along
. - If the field is of type
Cursor#FIELD_TYPE_BLOB
, then aSQLiteException
is thrown.
Parameters | |
---|---|
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
Returns | |
---|---|
long |
The value of the field as a long . |
getNumRows
public int getNumRows ()
Gets the number of rows in this window.
Returns | |
---|---|
int |
The number of rows in this cursor window. Value is 0 or greater |
getShort
public short getShort (int row, int column)
Gets the value of the field at the specified row and column index as a
short
.
The result is determined by invoking getLong(int, int)
and converting the
result to short
.
Parameters | |
---|---|
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
Returns | |
---|---|
short |
The value of the field as a short . |
getStartPosition
public int getStartPosition ()
Gets the start position of this cursor window.
The start position is the zero-based index of the first row that this window contains
relative to the entire result set of the Cursor
.
Returns | |
---|---|
int |
The zero-based start position. Value is 0 or greater |
getString
public String getString (int row, int column)
Gets the value of the field at the specified row and column index as a string.
The result is determined as follows:
- If the field is of type
Cursor#FIELD_TYPE_NULL
, then the result isnull
. - If the field is of type
Cursor#FIELD_TYPE_STRING
, then the result is the string value. - If the field is of type
Cursor#FIELD_TYPE_INTEGER
, then the result is a string representation of the integer in decimal, obtained by formatting the value with theprintf
family of functions using format specifier%lld
. - If the field is of type
Cursor#FIELD_TYPE_FLOAT
, then the result is a string representation of the floating-point value in decimal, obtained by formatting the value with theprintf
family of functions using format specifier%g
. - If the field is of type
Cursor#FIELD_TYPE_BLOB
, then aSQLiteException
is thrown.
Parameters | |
---|---|
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
Returns | |
---|---|
String |
The value of the field as a string. |
getType
public int getType (int row, int column)
Returns the type of the field at the specified row and column index.
Parameters | |
---|---|
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
Returns | |
---|---|
int |
The field type.
Value is Cursor.FIELD_TYPE_NULL , Cursor.FIELD_TYPE_INTEGER , Cursor.FIELD_TYPE_FLOAT , Cursor.FIELD_TYPE_STRING , or Cursor.FIELD_TYPE_BLOB |
isBlob
public boolean isBlob (int row, int column)
This method was deprecated
in API level 15.
Use getType(int, int)
instead.
Returns true if the field at the specified row and column index
has type Cursor#FIELD_TYPE_BLOB
or Cursor#FIELD_TYPE_NULL
.
Parameters | |
---|---|
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
Returns | |
---|---|
boolean |
True if the field has type Cursor#FIELD_TYPE_BLOB or
Cursor#FIELD_TYPE_NULL . |
isFloat
public boolean isFloat (int row, int column)
This method was deprecated
in API level 15.
Use getType(int, int)
instead.
Returns true if the field at the specified row and column index
has type Cursor#FIELD_TYPE_FLOAT
.
Parameters | |
---|---|
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
Returns | |
---|---|
boolean |
True if the field has type Cursor#FIELD_TYPE_FLOAT . |
isLong
public boolean isLong (int row, int column)
This method was deprecated
in API level 15.
Use getType(int, int)
instead.
Returns true if the field at the specified row and column index
has type Cursor#FIELD_TYPE_INTEGER
.
Parameters | |
---|---|
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
Returns | |
---|---|
boolean |
True if the field has type Cursor#FIELD_TYPE_INTEGER . |
isNull
public boolean isNull (int row, int column)
This method was deprecated
in API level 15.
Use getType(int, int)
instead.
Returns true if the field at the specified row and column index
has type Cursor#FIELD_TYPE_NULL
.
Parameters | |
---|---|
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
Returns | |
---|---|
boolean |
True if the field has type Cursor#FIELD_TYPE_NULL . |
isString
public boolean isString (int row, int column)
This method was deprecated
in API level 15.
Use getType(int, int)
instead.
Returns true if the field at the specified row and column index
has type Cursor#FIELD_TYPE_STRING
or Cursor#FIELD_TYPE_NULL
.
Parameters | |
---|---|
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
Returns | |
---|---|
boolean |
True if the field has type Cursor#FIELD_TYPE_STRING
or Cursor#FIELD_TYPE_NULL . |
newFromParcel
public static CursorWindow newFromParcel (Parcel p)
Parameters | |
---|---|
p |
Parcel |
Returns | |
---|---|
CursorWindow |
putBlob
public boolean putBlob (byte[] value, int row, int column)
Copies a byte array into the field at the specified row and column index.
Parameters | |
---|---|
value |
byte : The value to store. |
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
Returns | |
---|---|
boolean |
True if successful. |
putDouble
public boolean putDouble (double value, int row, int column)
Puts a double-precision floating point value into the field at the specified row and column index.
Parameters | |
---|---|
value |
double : The value to store. |
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
Returns | |
---|---|
boolean |
True if successful. |
putLong
public boolean putLong (long value, int row, int column)
Puts a long integer into the field at the specified row and column index.
Parameters | |
---|---|
value |
long : The value to store. |
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
Returns | |
---|---|
boolean |
True if successful. |
putNull
public boolean putNull (int row, int column)
Puts a null value into the field at the specified row and column index.
Parameters | |
---|---|
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
Returns | |
---|---|
boolean |
True if successful. |
putString
public boolean putString (String value, int row, int column)
Copies a string into the field at the specified row and column index.
Parameters | |
---|---|
value |
String : The value to store. |
row |
int : The zero-based row index.
Value is 0 or greater |
column |
int : The zero-based column index.
Value is 0 or greater |
Returns | |
---|---|
boolean |
True if successful. |
setNumColumns
public boolean setNumColumns (int columnNum)
Sets the number of columns in this window.
This method must be called before any rows are added to the window, otherwise it will fail to set the number of columns if it differs from the current number of columns.
Parameters | |
---|---|
columnNum |
int : The new number of columns.
Value is 0 or greater |
Returns | |
---|---|
boolean |
True if successful. |
setStartPosition
public void setStartPosition (int pos)
Sets the start position of this cursor window.
The start position is the zero-based index of the first row that this window contains
relative to the entire result set of the Cursor
.
Parameters | |
---|---|
pos |
int : The new zero-based start position.
Value is 0 or greater |
toString
public String toString ()
Returns a string representation of the object.
Returns | |
---|---|
String |
a string representation of the object. |
writeToParcel
public void writeToParcel (Parcel dest, int flags)
Flatten this object in to a Parcel.
Parameters | |
---|---|
dest |
Parcel : The Parcel in which the object should be written.
This value cannot be null . |
flags |
int : Additional flags about how the object should be written.
May be 0 or Parcelable.PARCELABLE_WRITE_RETURN_VALUE .
Value is either 0 or a combination of Parcelable.PARCELABLE_WRITE_RETURN_VALUE , and android.os.Parcelable.PARCELABLE_ELIDE_DUPLICATES |
Protected methods
finalize
protected void finalize ()
Called by the garbage collector on an object when garbage collection
determines that there are no more references to the object.
A subclass overrides the finalize
method to dispose of
system resources or to perform other cleanup.
The general contract of finalize
is that it is invoked
if and when the Java virtual
machine has determined that there is no longer any
means by which this object can be accessed by any thread that has
not yet died, except as a result of an action taken by the
finalization of some other object or class which is ready to be
finalized. The finalize
method may take any action, including
making this object available again to other threads; the usual purpose
of finalize
, however, is to perform cleanup actions before
the object is irrevocably discarded. For example, the finalize method
for an object that represents an input/output connection might perform
explicit I/O transactions to break the connection before the object is
permanently discarded.
The finalize
method of class Object
performs no
special action; it simply returns normally. Subclasses of
Object
may override this definition.
The Java programming language does not guarantee which thread will
invoke the finalize
method for any given object. It is
guaranteed, however, that the thread that invokes finalize will not
be holding any user-visible synchronization locks when finalize is
invoked. If an uncaught exception is thrown by the finalize method,
the exception is ignored and finalization of that object terminates.
After the finalize
method has been invoked for an object, no
further action is taken until the Java virtual machine has again
determined that there is no longer any means by which this object can
be accessed by any thread that has not yet died, including possible
actions by other objects or classes which are ready to be finalized,
at which point the object may be discarded.
The finalize
method is never invoked more than once by a Java
virtual machine for any given object.
Any exception thrown by the finalize
method causes
the finalization of this object to be halted, but is otherwise
ignored.
Throws | |
---|---|
Throwable |
onAllReferencesReleased
protected void onAllReferencesReleased ()
Called when the last reference to the object was released by
a call to releaseReference()
or close()
.