IT. Expert System.

Android Reference

Cursor

android.database

Interface Cursor

All Superinterfaces:

AutoCloseable, Closeable

All Known Subinterfaces:

CrossProcessCursor

All Known Implementing Classes:

AbstractCursor, AbstractWindowedCursor, BulkCursorToCursorAdaptor, CrossProcessCursorWrapper, CursorWrapper, MatrixCursor, MergeCursor, MockCursor, SQLiteCursor
```
public interface Cursor
extends Closeable
```
This interface provides random read-write access to the result set returned by a database query. Cursor implementations are not required to be synchronized so code using a Cursor from multiple threads should perform its own synchronization when using the Cursor.

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`FIELD_TYPE_BLOB` Value returned by `getType(int)` if the specified column type is blob
`static int`	`FIELD_TYPE_FLOAT` Value returned by `getType(int)` if the specified column type is float
`static int`	`FIELD_TYPE_INTEGER` Value returned by `getType(int)` if the specified column type is integer
`static int`	`FIELD_TYPE_NULL` Value returned by `getType(int)` if the specified column is null
`static int`	`FIELD_TYPE_STRING` Value returned by `getType(int)` if the specified column type is string

Method Summary

Methods
Modifier and Type	Method and Description
`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()` Deprecated. Since `requery()` is deprecated, so too is this.
`byte[]`	`getBlob(int columnIndex)` 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.
`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 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.
`int`	`getPosition()` Returns the current position of the cursor in the row set.
`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.
`boolean`	`getWantsAllOnMoveCalls()` onMove() will only be called across processes if this method returns true.
`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`	`isClosed()` return true if the cursor is closed
`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`	`move(int offset)` Move the cursor by a relative amount, forward or backward, from the current position.
`boolean`	`moveToFirst()` Move the cursor to the first row.
`boolean`	`moveToLast()` Move the cursor to the last row.
`boolean`	`moveToNext()` Move the cursor to the next row.
`boolean`	`moveToPosition(int position)` Move the cursor to an absolute position.
`boolean`	`moveToPrevious()` 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()` Deprecated. 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.
`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.
`void`	`unregisterContentObserver(ContentObserver observer)` Unregister an observer that has previously been registered with this cursor via `registerContentObserver(android.database.ContentObserver)`.
`void`	`unregisterDataSetObserver(DataSetObserver observer)` Unregister an observer that has previously been registered with this cursor via `registerContentObserver(android.database.ContentObserver)`.

- Field Detail
  - FIELD_TYPE_NULL
```
static final int FIELD_TYPE_NULL
```
    Value returned by getType(int) if the specified column is null
    
    See Also:
    Constant Field Values
  - FIELD_TYPE_INTEGER
```
static final int FIELD_TYPE_INTEGER
```
    Value returned by getType(int) if the specified column type is integer
    
    See Also:
    Constant Field Values
  - FIELD_TYPE_FLOAT
```
static final int FIELD_TYPE_FLOAT
```
    Value returned by getType(int) if the specified column type is float
    
    See Also:
    Constant Field Values
  - FIELD_TYPE_STRING
```
static final int FIELD_TYPE_STRING
```
    Value returned by getType(int) if the specified column type is string
    
    See Also:
    Constant Field Values
  - FIELD_TYPE_BLOB
```
static final int FIELD_TYPE_BLOB
```
    Value returned by getType(int) if the specified column type is blob
    
    See Also:
    Constant Field Values
- Method Detail
  - getCount
```
int getCount()
```
    Returns the numbers of rows in the cursor.
    
    Returns:
    the number of rows in the cursor.
  - getPosition
```
int getPosition()
```
    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.
  - move
```
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.
  - moveToPosition
```
boolean moveToPosition(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.
  - moveToFirst
```
boolean moveToFirst()
```
    Move the cursor to the first row.
    This method will return false if the cursor is empty.
    
    Returns:
    whether the move succeeded.
  - moveToLast
```
boolean moveToLast()
```
    Move the cursor to the last row.
    This method will return false if the cursor is empty.
    
    Returns:
    whether the move succeeded.
  - moveToNext
```
boolean moveToNext()
```
    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.
  - moveToPrevious
```
boolean moveToPrevious()
```
    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.
  - isFirst
```
boolean isFirst()
```
    Returns whether the cursor is pointing to the first row.
    
    Returns:
    whether the cursor is pointing at the first entry.
  - isLast
```
boolean isLast()
```
    Returns whether the cursor is pointing to the last row.
    
    Returns:
    whether the cursor is pointing at the last entry.
  - isBeforeFirst
```
boolean isBeforeFirst()
```
    Returns whether the cursor is pointing to the position before the first row.
    
    Returns:
    whether the cursor is before the first result.
  - isAfterLast
```
boolean isAfterLast()
```
    Returns whether the cursor is pointing to the position after the last row.
    
    Returns:
    whether the cursor is after the last result.
  - getColumnIndex
```
int getColumnIndex(String columnName)
```
    Returns the zero-based index for the given column name, or -1 if the column doesn't exist. If you expect the column to exist use getColumnIndexOrThrow(String) instead, which will make the error more clear.
    
    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.
    See Also:
    getColumnIndexOrThrow(String)
  - getColumnIndexOrThrow
```
int getColumnIndexOrThrow(String columnName)
                          throws IllegalArgumentException
```
    Returns the zero-based index for the given column name, or throws IllegalArgumentException if the column doesn't exist. If you're not sure if a column will exist or not use getColumnIndex(String) and check for -1, which is more efficient than catching the exceptions.
    
    Parameters:
    columnName - the name of the target column.
    
    Returns:
    the zero-based column index for the given column name
    
    Throws:
    
    IllegalArgumentException - if the column does not exist
    See Also:
    getColumnIndex(String)
  - getColumnName
```
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.
  - getColumnNames
```
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.
  - getColumnCount
```
int getColumnCount()
```
    Return total number of columns
    
    Returns:
    number of columns
  - 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 - the zero-based index of the target column.
    
    Returns:
    the value of that column as a byte array.
  - 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 - the zero-based index of the target column.
    
    Returns:
    the value of that column as a String.
  - 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 - the zero-based index of the target column. if the target column is null, return buffer
    buffer - the buffer to copy the text into.
  - 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 - the zero-based index of the target column.
    
    Returns:
    the value of that column as a short.
  - 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 - the zero-based index of the target column.
    
    Returns:
    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 - the zero-based index of the target column.
    
    Returns:
    the value of that column as a long.
  - 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 - the zero-based index of the target column.
    
    Returns:
    the value of that column as a float.
  - 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 - the zero-based index of the target column.
    
    Returns:
    the value of that column as a double.
  - 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 - the zero-based index of the target column.
    
    Returns:
    column value type
  - isNull
```
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.
  - deactivate
```
void deactivate()
```
    Deprecated. Since requery() is deprecated, so too is this.
    
    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.
  - requery
```
@Deprecated
boolean requery()
```
    Deprecated. 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.
    
    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.
  - close
```
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.
    
    Specified by:
    
    close in interface AutoCloseable
    
    Specified by:
    
    close in interface Closeable
  - isClosed
```
boolean isClosed()
```
    return true if the cursor is closed
    
    Returns:
    true if the cursor is closed.
  - registerContentObserver
```
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.
    See Also:
    unregisterContentObserver(ContentObserver)
  - unregisterContentObserver
```
void unregisterContentObserver(ContentObserver observer)
```
    Unregister an observer that has previously been registered with this cursor via registerContentObserver(android.database.ContentObserver).
    
    Parameters:
    observer - the object to unregister.
    See Also:
    registerContentObserver(ContentObserver)
  - registerDataSetObserver
```
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.
    See Also:
    unregisterDataSetObserver(DataSetObserver)
  - unregisterDataSetObserver
```
void unregisterDataSetObserver(DataSetObserver observer)
```
    Unregister an observer that has previously been registered with this cursor via registerContentObserver(android.database.ContentObserver).
    
    Parameters:
    observer - the object to unregister.
    See Also:
    registerDataSetObserver(DataSetObserver)
  - setNotificationUri
```
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.
  - getWantsAllOnMoveCalls
```
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().
  - getExtras
```
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.EMPTY if there are no values. Never null.
  - respond
```
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.EMPTY. Never null.
    
    Returns:
    extra values, or Bundle.EMPTY. Never null.

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IT. Expert System.

Android Reference

Cursor

Interface Cursor

Field Summary

Method Summary

Field Detail

FIELD_TYPE_NULL

FIELD_TYPE_INTEGER

FIELD_TYPE_FLOAT

FIELD_TYPE_STRING

FIELD_TYPE_BLOB

Method Detail

getCount

getPosition

move

moveToPosition

moveToFirst

moveToLast

moveToNext

moveToPrevious

isFirst

isLast

isBeforeFirst

isAfterLast

getColumnIndex

getColumnIndexOrThrow

getColumnName

getColumnNames

getColumnCount

getBlob

getString

copyStringToBuffer

getShort

getInt

getLong

getFloat

getDouble

getType

isNull

deactivate

requery

close

isClosed

registerContentObserver

unregisterContentObserver

registerDataSetObserver

unregisterDataSetObserver

setNotificationUri

getWantsAllOnMoveCalls

getExtras

respond

Android Reference

Java basics

Java Enterprise Edition (EE)

Java Standard Edition (SE)

SQL

HTML

PHP

CSS

Java Script

MYSQL

JQUERY

VBS

REGEX

C

C++

C#

Design patterns

RFC (standard status)

RFC (proposed standard status)

RFC (draft standard status)

RFC (informational status)

RFC (experimental status)

RFC (best current practice status)

RFC (historic status)

RFC (unknown status)

IT dictionary