CrossProcessCursor

Kotlin |Java

interface CrossProcessCursor : Cursor

android.database.CrossProcessCursor

Known Direct Subclasses

AbstractCursor, CrossProcessCursorWrapper

AbstractCursor	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.
CrossProcessCursorWrapper	Cursor wrapper that implements `CrossProcessCursor`.

Known Indirect Subclasses

AbstractWindowedCursor, MatrixCursor, MergeCursor, SQLiteCursor

AbstractWindowedCursor	A base class for Cursors that store their data in `CursorWindow`s.
MatrixCursor	A mutable cursor implementation backed by an array of `Object`s.
MergeCursor	A convenience class that lets you present an array of Cursors as a single linear Cursor.
SQLiteCursor	A Cursor implementation that exposes results from a query on a `SQLiteDatabase`.

A cross process cursor is an extension of a Cursor that also supports usage from remote processes.

The contents of a cross process cursor are marshalled to the remote process by filling CursorWindow objects using fillWindow. As an optimization, the cursor can provide a pre-filled window to use via getWindow thereby obviating the need to copy the data to yet another cursor window.

Summary

Inherited constants

From class Cursor

`Int`	`FIELD_TYPE_BLOB` Value returned by `getType(int)` if the specified column type is blob
`Int`	`FIELD_TYPE_FLOAT` Value returned by `getType(int)` if the specified column type is float
`Int`	`FIELD_TYPE_INTEGER` Value returned by `getType(int)` if the specified column type is integer
`Int`	`FIELD_TYPE_NULL` Value returned by `getType(int)` if the specified column is null
`Int`	`FIELD_TYPE_STRING` Value returned by `getType(int)` if the specified column type is string

Public methods
abstract Unit	`fillWindow(position: Int, window: CursorWindow!)` Copies cursor data into the window.
abstract CursorWindow!	`getWindow()` Returns a pre-filled window that contains the data within this cursor.
abstract 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.

Inherited functions

From class Cursor

`Unit`	`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.
`Unit`	`copyStringToBuffer(columnIndex: Int, buffer: CharArrayBuffer!)` 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
`Unit`	`deactivate()` 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.
`ByteArray!`	`getBlob(columnIndex: Int)` 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.
`Int`	`getColumnCount()` Return total number of columns
`Int`	`getColumnIndex(columnName: String!)` 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(java.lang.String)` instead, which will make the error more clear.
`Int`	`getColumnIndexOrThrow(columnName: String!)` 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(java.lang.String)` and check for -1, which is more efficient than catching the exceptions.
`String!`	`getColumnName(columnIndex: Int)` Returns the column name at the given zero-based column index.
`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(columnIndex: Int)` 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.
`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.
`Float`	`getFloat(columnIndex: Int)` 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.
`Int`	`getInt(columnIndex: 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.
`Long`	`getLong(columnIndex: Int)` 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.
`Uri!`	`getNotificationUri()` Return the URI at which notifications of changes in this Cursor's data will be delivered, as previously set by `setNotificationUri`.
`MutableList<Uri!>?`	`getNotificationUris()` Return the URIs at which notifications of changes in this Cursor's data will be delivered, as previously set by `setNotificationUris`. If this is not implemented, this is equivalent to calling `getNotificationUri()`.
`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().
`Short`	`getShort(columnIndex: Int)` 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.
`String!`	`getString(columnIndex: Int)` 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.
`Int`	`getType(columnIndex: Int)` 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.
`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(columnIndex: 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. 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.
`Boolean`	`moveToFirst()` Move the cursor to the first row. This method will return false if the cursor is empty.
`Boolean`	`moveToLast()` Move the cursor to the last row. This method will return false if the cursor is empty.
`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.
`Boolean`	`moveToPosition(position: Int)` 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.
`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.
`Unit`	`registerContentObserver(observer: ContentObserver!)` 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.
`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().
`Boolean`	`requery()` 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.
`Bundle!`	`respond(extras: 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.
`Unit`	`setExtras(extras: Bundle!)` Sets a `Bundle` that will be returned by `getExtras()`.
`Unit`	`setNotificationUri(cr: ContentResolver!, 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. Calling this overrides any previous call to `setNotificationUris(android.content.ContentResolver,java.util.List)`.
`Unit`	`setNotificationUris(cr: ContentResolver, uris: MutableList<Uri!>)` Similar to `setNotificationUri(android.content.ContentResolver,android.net.Uri)`, except this version allows to watch multiple content URIs for changes. If this is not implemented, this is equivalent to calling `setNotificationUri(android.content.ContentResolver,android.net.Uri)` with the first URI in `uris`. Calling this overrides any previous call to `setNotificationUri(android.content.ContentResolver,android.net.Uri)`.
`Unit`	`unregisterContentObserver(observer: ContentObserver!)` Unregister an observer that has previously been registered with this cursor via `registerContentObserver`.
`Unit`	`unregisterDataSetObserver(observer: DataSetObserver!)` Unregister an observer that has previously been registered with this cursor via `registerContentObserver`.

Public methods

fillWindow

Added in API level 1

abstract 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.

getWindow

Added in API level 1

abstract fun getWindow(): CursorWindow!

Returns a pre-filled window that contains the data within this cursor.

In particular, the window contains the row indicated by Cursor#getPosition. The window's contents are automatically scrolled whenever the current row moved outside the range covered by the window.

Return
`CursorWindow!`	The pre-filled window, or null if none.

onMove

Added in API level 1

abstract 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.

This function should be called by methods such as moveToPosition(int), so it will typically not be called from outside of the cursor class itself.

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.