public abstract class AbstractCursor extends Object implements CrossProcessCursor
Modifier and Type | Class and Description |
---|---|
protected static class |
AbstractCursor.SelfContentObserver
Cursors use this class to track changes others make to their URI.
|
Modifier and Type | Field and Description |
---|---|
protected boolean |
mClosed
Deprecated.
Use
isClosed() instead. |
protected ContentResolver |
mContentResolver
Deprecated.
Do not use.
|
protected Long |
mCurrentRowID |
protected int |
mPos
Deprecated.
Use
getPosition() instead. |
protected int |
mRowIdColumnIndex |
protected HashMap<Long,Map<String,Object>> |
mUpdatedRows |
FIELD_TYPE_BLOB, FIELD_TYPE_FLOAT, FIELD_TYPE_INTEGER, FIELD_TYPE_NULL, FIELD_TYPE_STRING
Constructor and Description |
---|
AbstractCursor() |
Modifier and Type | Method and Description |
---|---|
protected void |
checkPosition()
This function throws CursorIndexOutOfBoundsException if
the cursor position is out of bounds.
|
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()
Deactivates the Cursor, making all calls on it fail until
Cursor.requery() is called. |
void |
fillWindow(int position,
CursorWindow window)
Copies cursor data into the window.
|
protected void |
finalize()
Called by the garbage collector on an object when garbage collection
determines that there are no more references to the object.
|
byte[] |
getBlob(int column)
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.
|
abstract 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(int column)
Returns the value of the requested column as a double.
|
Bundle |
getExtras()
Returns a bundle of extra values.
|
abstract float |
getFloat(int column)
Returns the value of the requested column as a float.
|
abstract int |
getInt(int column)
Returns the value of the requested column as an int.
|
abstract long |
getLong(int column)
Returns the value of the requested column as a long.
|
Uri |
getNotificationUri()
Return the URI at which notifications of changes in this Cursor's data
will be delivered, as previously set by
Cursor.setNotificationUri(android.content.ContentResolver, android.net.Uri) . |
int |
getPosition()
Returns the current position of the cursor in the row set.
|
abstract short |
getShort(int column)
Returns the value of the requested column as a short.
|
abstract String |
getString(int column)
Returns the value of the requested column as a String.
|
int |
getType(int column)
Returns data type of the given column's value.
|
protected Object |
getUpdatedField(int columnIndex)
Deprecated.
Always returns null since Cursors do not support updating rows
|
boolean |
getWantsAllOnMoveCalls()
onMove() will only be called across processes if this method returns true.
|
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.
|
boolean |
isClosed()
return true if the cursor is closed
|
protected boolean |
isFieldUpdated(int columnIndex)
Deprecated.
Always returns false since Cursors do not support updating rows
|
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(int column)
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.
|
protected void |
onChange(boolean selfChange)
Subclasses must call this method when they finish committing updates to notify all
observers.
|
protected void |
onDeactivateOrClose() |
boolean |
onMove(int oldPosition,
int newPosition)
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.
|
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
Cursor.requery() , Cursor.deactivate() , or Cursor.close() . |
boolean |
requery()
Performs the query that created the cursor again, refreshing its
contents.
|
Bundle |
respond(Bundle extras)
This is an out-of-band way for the the user of a cursor to communicate with the cursor.
|
void |
setExtras(Bundle extras)
Sets a
Bundle that will be returned by Cursor.getExtras() . |
void |
setNotificationUri(ContentResolver cr,
Uri notifyUri)
Specifies a content URI to watch for changes.
|
void |
setNotificationUri(ContentResolver cr,
Uri notifyUri,
int userHandle) |
void |
unregisterContentObserver(ContentObserver observer)
Unregister an observer that has previously been registered with this
cursor via
Cursor.registerContentObserver(android.database.ContentObserver) . |
void |
unregisterDataSetObserver(DataSetObserver observer)
Unregister an observer that has previously been registered with this
cursor via
Cursor.registerContentObserver(android.database.ContentObserver) . |
protected int mRowIdColumnIndex
protected Long mCurrentRowID
@Deprecated protected int mPos
getPosition()
instead.@Deprecated protected boolean mClosed
isClosed()
instead.@Deprecated protected ContentResolver mContentResolver
public abstract int getCount()
Cursor
public abstract String[] getColumnNames()
Cursor
getColumnNames
in interface Cursor
public abstract String getString(int column)
Cursor
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.
public abstract short getShort(int column)
Cursor
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.
public abstract int getInt(int column)
Cursor
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.
public abstract long getLong(int column)
Cursor
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.
public abstract float getFloat(int column)
Cursor
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.
public abstract double getDouble(int column)
Cursor
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.
public abstract boolean isNull(int column)
Cursor
true
if the value in the indicated column is null.public int getType(int column)
Cursor
Cursor.getInt(int)
, Cursor.getFloat(int)
etc.
Returned column types are
public byte[] getBlob(int column)
Cursor
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.
public CursorWindow getWindow()
CursorWindow
, returns a pre-filled
window with the contents of the cursor, otherwise null.getWindow
in interface CrossProcessCursor
public int getColumnCount()
Cursor
getColumnCount
in interface Cursor
public void deactivate()
Cursor
Cursor.requery()
is called.
Inactive Cursors use fewer resources than active Cursors.
Calling Cursor.requery()
will make the cursor active again.deactivate
in interface Cursor
protected void onDeactivateOrClose()
public boolean requery()
Cursor
Cursor.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.public boolean isClosed()
Cursor
public void close()
Cursor
Cursor.deactivate()
a call to Cursor.requery()
will not make the Cursor valid
again.public boolean onMove(int oldPosition, int newPosition)
onMove
in interface CrossProcessCursor
oldPosition
- the position that we're moving fromnewPosition
- the position that we're moving topublic void copyStringToBuffer(int columnIndex, CharArrayBuffer buffer)
Cursor
copyStringToBuffer
in interface Cursor
columnIndex
- the zero-based index of the target column.
if the target column is null, return bufferbuffer
- the buffer to copy the text into.public final int getPosition()
Cursor
getPosition
in interface Cursor
public final boolean moveToPosition(int position)
Cursor
This method will return true if the request destination was reachable, otherwise, it returns false.
moveToPosition
in interface Cursor
position
- the zero-based position to move to.public void fillWindow(int position, CursorWindow window)
CrossProcessCursor
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 Cursor.getPosition()
,
is not changed by this method.
fillWindow
in interface CrossProcessCursor
position
- The zero-based index of the first row to copy into the window.window
- The window to fill.public final boolean move(int offset)
Cursor
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.
public final boolean moveToFirst()
Cursor
This method will return false if the cursor is empty.
moveToFirst
in interface Cursor
public final boolean moveToLast()
Cursor
This method will return false if the cursor is empty.
moveToLast
in interface Cursor
public final boolean moveToNext()
Cursor
This method will return false if the cursor is already past the last entry in the result set.
moveToNext
in interface Cursor
public final boolean moveToPrevious()
Cursor
This method will return false if the cursor is already before the first entry in the result set.
moveToPrevious
in interface Cursor
public final boolean isFirst()
Cursor
public final boolean isLast()
Cursor
public final boolean isBeforeFirst()
Cursor
isBeforeFirst
in interface Cursor
public final boolean isAfterLast()
Cursor
isAfterLast
in interface Cursor
public int getColumnIndex(String columnName)
Cursor
Cursor.getColumnIndexOrThrow(String)
instead, which
will make the error more clear.getColumnIndex
in interface Cursor
columnName
- the name of the target column.Cursor.getColumnIndexOrThrow(String)
public int getColumnIndexOrThrow(String columnName)
Cursor
IllegalArgumentException
if the column doesn't exist. If you're not sure if
a column will exist or not use Cursor.getColumnIndex(String)
and check for -1, which
is more efficient than catching the exceptions.getColumnIndexOrThrow
in interface Cursor
columnName
- the name of the target column.Cursor.getColumnIndex(String)
public String getColumnName(int columnIndex)
Cursor
getColumnName
in interface Cursor
columnIndex
- the zero-based index of the target column.public void registerContentObserver(ContentObserver observer)
Cursor
Cursor.requery()
is called.registerContentObserver
in interface Cursor
observer
- the object that gets notified when the content backing the cursor changes.Cursor.unregisterContentObserver(ContentObserver)
public void unregisterContentObserver(ContentObserver observer)
Cursor
Cursor.registerContentObserver(android.database.ContentObserver)
.unregisterContentObserver
in interface Cursor
observer
- the object to unregister.Cursor.registerContentObserver(ContentObserver)
public void registerDataSetObserver(DataSetObserver observer)
Cursor
Cursor.requery()
, Cursor.deactivate()
, or Cursor.close()
.registerDataSetObserver
in interface Cursor
observer
- the object that gets notified when the cursors data set changes.Cursor.unregisterDataSetObserver(DataSetObserver)
public void unregisterDataSetObserver(DataSetObserver observer)
Cursor
Cursor.registerContentObserver(android.database.ContentObserver)
.unregisterDataSetObserver
in interface Cursor
observer
- the object to unregister.Cursor.registerDataSetObserver(DataSetObserver)
protected void onChange(boolean selfChange)
selfChange
- public void setNotificationUri(ContentResolver cr, Uri notifyUri)
setNotificationUri
in interface Cursor
cr
- The content resolver from the caller's context.notifyUri
- The URI to watch for changes. This can be a
specific row URI, or a base URI for a whole class of content.public void setNotificationUri(ContentResolver cr, Uri notifyUri, int userHandle)
public Uri getNotificationUri()
Cursor
Cursor.setNotificationUri(android.content.ContentResolver, android.net.Uri)
.getNotificationUri
in interface Cursor
ContentResolver.registerContentObserver
to find out about changes to this Cursor's
data. May be null if no notification URI has been set.public boolean getWantsAllOnMoveCalls()
Cursor
getWantsAllOnMoveCalls
in interface Cursor
public void setExtras(Bundle extras)
Cursor
Bundle
that will be returned by Cursor.getExtras()
.public Bundle getExtras()
Cursor
These values may only change when requery is called.
getExtras
in interface Cursor
Bundle.EMPTY
if there
are no values. Never null
.public Bundle respond(Bundle extras)
Cursor
One use of this is to tell a cursor that it should retry its network request after it reported an error.
respond
in interface Cursor
extras
- extra values, or Bundle.EMPTY
.
Never null
.Bundle.EMPTY
.
Never null
.@Deprecated protected boolean isFieldUpdated(int columnIndex)
@Deprecated protected Object getUpdatedField(int columnIndex)
protected void checkPosition()
CursorIndexOutOfBoundsException
protected void finalize()
Object
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 JavaTM 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.