AbstractCursor

abstract class AbstractCursor : CrossProcessCursor

This is an abstract cursor class that handles a lot of the common code that all cursors need to deal with and is provided for convenience reasons.

Summary

Nested classes
open	`SelfContentObserver` Cursors use this class to track changes others make to their URI.

Public constructors
`AbstractCursor()`

Public methods
open Unit	`close()` Closes the Cursor, releasing all of its resources and making it completely invalid.
open Unit	`copyStringToBuffer(columnIndex: Int, buffer: CharArrayBuffer!)` Retrieves the requested column text and stores it in the buffer provided.
open Unit	`deactivate()` Deactivates the Cursor, making all calls on it fail until `requery` is called.
open Unit	`fillWindow(position: Int, window: CursorWindow!)` Copies cursor data into the window.
open ByteArray!	`getBlob(column: Int)` Returns the value of the requested column as a byte array.
open Int	`getColumnCount()` Return total number of columns
open Int	`getColumnIndex(columnName: String!)` Returns the zero-based index for the given column name, or -1 if the column doesn't exist.
open Int	`getColumnIndexOrThrow(columnName: String!)` Returns the zero-based index for the given column name, or throws `IllegalArgumentException` if the column doesn't exist.
open String!	`getColumnName(columnIndex: Int)` Returns the column name at the given zero-based column index.
abstract 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.
abstract Int	`getCount()` Returns the numbers of rows in the cursor.
abstract Double	`getDouble(column: Int)` Returns the value of the requested column as a double.
open Bundle!	`getExtras()` Returns a bundle of extra values.
abstract Float	`getFloat(column: Int)` Returns the value of the requested column as a float.
abstract Int	`getInt(column: Int)` Returns the value of the requested column as an int.
abstract Long	`getLong(column: Int)` Returns the value of the requested column as a long.
open Uri!	`getNotificationUri()` Return the URI at which notifications of changes in this Cursor's data will be delivered, as previously set by `setNotificationUri`.
open MutableList<Uri!>?	`getNotificationUris()` Return the URIs at which notifications of changes in this Cursor's data will be delivered, as previously set by `setNotificationUris`.
Int	`getPosition()` Returns the current position of the cursor in the row set.
abstract Short	`getShort(column: Int)` Returns the value of the requested column as a short.
abstract String!	`getString(column: Int)` Returns the value of the requested column as a String.
open Int	`getType(column: Int)` Returns data type of the given column's value.
open Boolean	`getWantsAllOnMoveCalls()` onMove() will only be called across processes if this method returns true.
open CursorWindow!	`getWindow()` If the cursor is backed by a `CursorWindow`, returns a pre-filled window with the contents of the cursor, otherwise null.
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.
open 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.
abstract Boolean	`isNull(column: Int)` Returns `true` if the value in the indicated column is null.
Boolean	`move(offset: Int)` 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(position: Int)` Move the cursor to an absolute position.
Boolean	`moveToPrevious()` Move the cursor to the previous row.
open Boolean	`onMove(oldPosition: Int, newPosition: Int)` 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.
open Unit	`registerContentObserver(observer: ContentObserver!)` Register an observer that is called when changes happen to the content backing this cursor.
open Unit	`registerDataSetObserver(observer: DataSetObserver!)` 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().
open Boolean	`requery()` Performs the query that created the cursor again, refreshing its contents.
open Bundle!	`respond(extras: Bundle!)` This is an out-of-band way for the user of a cursor to communicate with the cursor.
open Unit	`setExtras(extras: Bundle!)` Sets a `Bundle` that will be returned by `getExtras()`.
open Unit	`setNotificationUri(cr: ContentResolver!, notifyUri: Uri!)` Specifies a content URI to watch for changes.
open Unit	`setNotificationUris(cr: ContentResolver, notifyUris: MutableList<Uri!>)` Similar to `setNotificationUri(ContentResolver,Uri)`, except this version allows to watch multiple content URIs for changes.
open Unit	`unregisterContentObserver(observer: ContentObserver!)` Unregister an observer that has previously been registered with this cursor via `registerContentObserver`.
open Unit	`unregisterDataSetObserver(observer: DataSetObserver!)` Unregister an observer that has previously been registered with this cursor via `registerContentObserver`.

Protected methods
open Unit	`checkPosition()` This function throws CursorIndexOutOfBoundsException if the cursor position is out of bounds.
open Unit	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
open Any!	`getUpdatedField(columnIndex: Int)`
open Boolean	`isFieldUpdated(columnIndex: Int)`
open Unit	`onChange(selfChange: Boolean)` Subclasses must call this method when they finish committing updates to notify all observers.

Properties
Boolean	`mClosed`
ContentResolver!	`mContentResolver`
Int	`mPos`

Public constructors

AbstractCursor()

Public methods

close

open fun close(): Unit

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.

Exceptions
`java.lang.Exception`	if this resource cannot be closed
`java.io.IOException`	if an I/O error occurs

copyStringToBuffer

open fun copyStringToBuffer(
    columnIndex: Int, 
    buffer: CharArrayBuffer!
): Unit

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. Value is 0 or greater
`buffer`	CharArrayBuffer!: the buffer to copy the text into.

deactivate

open fun deactivate(): Unit

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.

fillWindow

open fun fillWindow(
    position: Int, 
    window: CursorWindow!
): Unit

Copies cursor data into the window.

Clears the window and fills it with data beginning at the requested row position until all of the data in the cursor is exhausted or the window runs out of space.

The filled window uses the same row indices as the original cursor. For example, if you fill a window starting from row 5 from the cursor, you can query the contents of row 5 from the window just by asking it for row 5 because there is a direct correspondence between the row indices used by the cursor and the window.

The current position of the cursor, as returned by getPosition, is not changed by this method.

Parameters
`position`	Int: The zero-based index of the first row to copy into the window.
`window`	CursorWindow!: The window to fill.

getBlob

open fun getBlob(column: Int): ByteArray!

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. Value is 0 or greater

Return
`ByteArray!`	the value of that column as a byte array.

getColumnCount

open fun getColumnCount(): Int

Return total number of columns

Return
`Int`	number of columns. Value is 0 or greater

getColumnIndex

open fun getColumnIndex(columnName: String!): Int

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`	String!: the name of the target column.

Return
`Int`	the zero-based column index for the given column name, or -1 if the column name does not exist. Value is -1 or greater

getColumnIndexOrThrow

open fun getColumnIndexOrThrow(columnName: String!): Int

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`	String!: the name of the target column.

Return
`Int`	the zero-based column index for the given column name. Value is 0 or greater

Exceptions
`java.lang.IllegalArgumentException`	if the column does not exist

getColumnName

open fun getColumnName(columnIndex: Int): String!

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

Parameters
`columnIndex`	Int: the zero-based index of the target column. Value is 0 or greater

Return
`String!`	the column name for the given column index.

getColumnNames

abstract fun getColumnNames(): Array<String!>!

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.

Return
`Array<String!>!`	the names of the columns returned in this query.

getCount

abstract fun getCount(): Int

Returns the numbers of rows in the cursor.

Return
`Int`	the number of rows in the cursor. Value is 0 or greater

getDouble

abstract fun getDouble(column: Int): Double

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. Value is 0 or greater

Return
`Double`	the value of that column as a double.

open fun getExtras(): Bundle!

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.

Return
`Bundle!`	cursor-defined values, or `Bundle.EMPTY` if there are no values. Never `null`.

getFloat

abstract fun getFloat(column: Int): Float

Returns the value of the requested column as a float.

Parameters
`columnIndex`	the zero-based index of the target column. Value is 0 or greater

Return
`Float`	the value of that column as a float.

getInt

abstract fun getInt(column: Int): Int

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. Value is 0 or greater

Return
`Int`	the value of that column as an int.

getLong

abstract fun getLong(column: Int): Long

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. Value is 0 or greater

Return
`Long`	the value of that column as a long.

getNotificationUri

open fun getNotificationUri(): Uri!

Return the URI at which notifications of changes in this Cursor's data will be delivered, as previously set by setNotificationUri.

Return
`Uri!`	Returns a URI that can be used with `ContentResolver.registerContentObserver` to find out about changes to this Cursor's data. May be null if no notification URI has been set.

getPosition

fun getPosition(): Int

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().

Return
`Int`	the current cursor position. Value is -1 or greater

getShort

abstract fun getShort(column: Int): Short

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. Value is 0 or greater

Return
`Short`	the value of that column as a short.

getString

abstract fun getString(column: Int): String!

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. Value is 0 or greater

Return
`String!`	the value of that column as a String.

getWantsAllOnMoveCalls

open fun getWantsAllOnMoveCalls(): Boolean

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

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

getWindow

open fun getWindow(): CursorWindow!

If the cursor is backed by a CursorWindow, returns a pre-filled window with the contents of the cursor, otherwise null.

Return
`CursorWindow!`	The pre-filled window that backs this cursor, or null if none.

isAfterLast

fun isAfterLast(): Boolean

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

Return
`Boolean`	whether the cursor is after the last result.

isBeforeFirst

fun isBeforeFirst(): Boolean

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

Return
`Boolean`	whether the cursor is before the first result.

isClosed

open fun isClosed(): Boolean

return true if the cursor is closed

Return
`Boolean`	true if the cursor is closed.

isFirst

fun isFirst(): Boolean

Returns whether the cursor is pointing to the first row.

Return
`Boolean`	whether the cursor is pointing at the first entry.

isLast

fun isLast(): Boolean

Returns whether the cursor is pointing to the last row.

Return
`Boolean`	whether the cursor is pointing at the last entry.

isNull

abstract fun isNull(column: Int): Boolean

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

Parameters
`columnIndex`	the zero-based index of the target column. Value is 0 or greater

Return
`Boolean`	whether the column value is null.

move

fun move(offset: Int): Boolean

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`	Int: the offset to be applied from the current position.

Return
`Boolean`	whether the requested move fully succeeded.

moveToFirst

fun moveToFirst(): Boolean

Move the cursor to the first row.

This method will return false if the cursor is empty.

Return
`Boolean`	whether the move succeeded.

moveToLast

fun moveToLast(): Boolean

Move the cursor to the last row.

This method will return false if the cursor is empty.

Return
`Boolean`	whether the move succeeded.

moveToNext

fun moveToNext(): Boolean

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.

Return
`Boolean`	whether the move succeeded.

moveToPosition

fun moveToPosition(position: Int): Boolean

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`	Int: the zero-based position to move to. Value is -1 or greater

Return
`Boolean`	whether the requested move fully succeeded.

moveToPrevious

fun moveToPrevious(): Boolean

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.

Return
`Boolean`	whether the move succeeded.

onMove

open fun onMove(
    oldPosition: Int, 
    newPosition: Int
): Boolean

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`	Int: the position that we're moving from
`newPosition`	Int: the position that we're moving to

Return
`Boolean`	true if the move is successful, false otherwise

registerContentObserver

open fun registerContentObserver(observer: ContentObserver!): Unit

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`	ContentObserver!: the object that gets notified when the content backing the cursor changes.

registerDataSetObserver

open fun registerDataSetObserver(observer: DataSetObserver!): Unit

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`	DataSetObserver!: the object that gets notified when the cursors data set changes.

requery

open fun requery(): Boolean

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.

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

respond

open fun respond(extras: Bundle!): Bundle!

This is an out-of-band way for 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`	Bundle!: extra values, or `Bundle.EMPTY`. Never `null`.

Return
`Bundle!`	extra values, or `Bundle.EMPTY`. Never `null`.

setNotificationUri

open fun setNotificationUri(
    cr: ContentResolver!, 
    notifyUri: Uri!
): Unit

Specifies a content URI to watch for changes.

Parameters
`cr`	ContentResolver!: The content resolver from the caller's context.
`uri`	The content URI to watch.
`notifyUri`	Uri!: The URI to watch for changes. This can be a specific row URI, or a base URI for a whole class of content.

Protected methods

checkPosition

protected open fun checkPosition(): Unit

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.

Exceptions
`android.database.CursorIndexOutOfBoundsException`

finalize

protected open fun finalize(): Unit

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.

Exceptions
`java.lang.Throwable`	the `Exception` raised by this method

getUpdatedField

protected open fun getUpdatedField(columnIndex: Int): Any!

Deprecated: Always returns null since Cursors do not support updating rows

isFieldUpdated

protected open fun isFieldUpdated(columnIndex: Int): Boolean

Deprecated: Always returns false since Cursors do not support updating rows

onChange

protected open fun onChange(selfChange: Boolean): Unit

Subclasses must call this method when they finish committing updates to notify all observers.

Parameters
`selfChange`	Boolean:

Properties

mClosed

protected var mClosed: Boolean

Deprecated: Use isClosed() instead.

mContentResolver

protected var mContentResolver: ContentResolver!

Deprecated: Do not use.

mPos

protected var mPos: Int

Deprecated: Use getPosition() instead.