AbstractWindowedCursor
abstract class AbstractWindowedCursor : AbstractCursor
A base class for Cursors that store their data in CursorWindows.
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 |
| open Unit |
Retrieves the requested column text and stores it in the buffer provided.
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| open ByteArray! |
Returns the value of the requested column as a byte array.
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| open Double |
Returns the value of the requested column as a double.
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| open Float |
Returns the value of the requested column as a float.
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| open Int |
Returns the value of the requested column as an int.
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| open Long |
Returns the value of the requested column as a long.
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| open Short |
Returns the value of the requested column as a short.
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| open String! |
Returns the value of the requested column as a String.
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| open Int |
Returns data type of the given column's value.
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| open CursorWindow! |
If the cursor is backed by a CursorWindow, returns a pre-filled window with the contents of the cursor, otherwise null.
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| open Boolean |
Returns true if the cursor has an associated cursor window.
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| open Boolean |
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| open Boolean |
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| open Boolean |
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| open Boolean |
Returns true if the value in the indicated column is null.
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| open Boolean |
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| open Unit |
Sets a new cursor window for the cursor to use.
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| Protected methods |
| open Unit |
This function throws CursorIndexOutOfBoundsException if the cursor position is out of bounds.
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| Inherited functions |
From class AbstractCursor
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.
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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.
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Unit |
fillWindow(position: Int, window: CursorWindow!)
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.
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Unit |
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.
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Int |
getColumnCount()
Return total number of columns
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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.
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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.
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String! |
getColumnName(columnIndex: Int)
Returns the column name at the given zero-based column index.
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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.
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Int |
getCount()
Returns the numbers of rows in the cursor.
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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.
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Uri! |
getNotificationUri()
Return the URI at which notifications of changes in this Cursor's data will be delivered, as previously set by setNotificationUri.
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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().
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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().
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Any! |
getUpdatedField(columnIndex: Int)
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Boolean |
getWantsAllOnMoveCalls()
onMove() will only be called across processes if this method returns true.
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Boolean |
isAfterLast()
Returns whether the cursor is pointing to the position after the last row.
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Boolean |
isBeforeFirst()
Returns whether the cursor is pointing to the position before the first row.
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Boolean |
isClosed()
return true if the cursor is closed
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Boolean |
isFieldUpdated(columnIndex: Int)
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Boolean |
isFirst()
Returns whether the cursor is pointing to the first row.
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Boolean |
isLast()
Returns whether the cursor is pointing to the last row.
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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.
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Boolean |
moveToFirst()
Move the cursor to the first row.
This method will return false if the cursor is empty.
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Boolean |
moveToLast()
Move the cursor to the last row.
This method will return false if the cursor is empty.
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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.
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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.
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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.
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Unit |
onChange(selfChange: Boolean)
Subclasses must call this method when they finish committing updates to notify all observers.
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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. If it returns false the move function will also do so and the cursor will scroll to the beforeFirst position.
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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.
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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().
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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.
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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.
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Unit |
setExtras(extras: Bundle!)
Sets a Bundle that will be returned by getExtras().
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Unit |
setNotificationUri(cr: ContentResolver!, notifyUri: Uri!)
Specifies a content URI to watch for changes.
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Unit |
setNotificationUris(cr: ContentResolver, notifyUris: 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).
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Unit |
unregisterContentObserver(observer: ContentObserver!)
Unregister an observer that has previously been registered with this cursor via registerContentObserver.
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Unit |
unregisterDataSetObserver(observer: DataSetObserver!)
Unregister an observer that has previously been registered with this cursor via registerContentObserver.
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| Properties |
| CursorWindow! |
The cursor window owned by this cursor.
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Public constructors
AbstractWindowedCursor
AbstractWindowedCursor()
Public methods
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. |
getBlob
open fun getBlob(columnIndex: 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 |
Int: the zero-based index of the target column.
Value is 0 or greater |
| Return |
ByteArray! |
the value of that column as a byte array. |
getDouble
open fun getDouble(columnIndex: 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 |
Int: the zero-based index of the target column.
Value is 0 or greater |
| Return |
Double |
the value of that column as a double. |
getFloat
open fun getFloat(columnIndex: Int): Float
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.
Value is 0 or greater |
| Return |
Float |
the value of that column as a float. |
getInt
open fun getInt(columnIndex: 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 |
Int: the zero-based index of the target column.
Value is 0 or greater |
| Return |
Int |
the value of that column as an int. |
getLong
open fun getLong(columnIndex: 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 |
Int: the zero-based index of the target column.
Value is 0 or greater |
| Return |
Long |
the value of that column as a long. |
getShort
open fun getShort(columnIndex: 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 |
Int: the zero-based index of the target column.
Value is 0 or greater |
| Return |
Short |
the value of that column as a short. |
getString
open fun getString(columnIndex: 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 |
Int: the zero-based index of the target column.
Value is 0 or greater |
| Return |
String! |
the value of that column as a String. |
getType
open fun getType(columnIndex: Int): 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.
| Parameters |
columnIndex |
Int: the zero-based index of the target column.
Value is 0 or greater |
| Return |
Int |
column value type.
Value is one of the following:
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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. |
hasWindow
open fun hasWindow(): Boolean
Returns true if the cursor has an associated cursor window.
| Return |
Boolean |
True if the cursor has an associated cursor window. |
isBlob
open fun isBlob(columnIndex: Int): Boolean
Deprecated: Use #getType
isFloat
open fun isFloat(columnIndex: Int): Boolean
Deprecated: Use #getType
isLong
open fun isLong(columnIndex: Int): Boolean
Deprecated: Use #getType
isNull
open fun isNull(columnIndex: Int): Boolean
Returns true if the value in the indicated column is null.
| Parameters |
columnIndex |
Int: the zero-based index of the target column.
Value is 0 or greater |
| Return |
Boolean |
whether the column value is null. |
isString
open fun isString(columnIndex: Int): Boolean
Deprecated: Use #getType
setWindow
open fun setWindow(window: CursorWindow!): Unit
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
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 |
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Properties
mWindow
protected var mWindow: CursorWindow!
The cursor window owned by this cursor.
