java.lang.Object | ||
↳ | android.database.AbstractCursor | |
↳ | android.database.MergeCursor |
A convience class that lets you present an array of Cursors as a single linear Cursor. The schema of the cursors presented is entirely up to the creator of the MergeCursor, and may be different if that is desired. Calls to getColumns, getColumnIndex, etc will return the value for the row that the MergeCursor is currently pointing at.
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Inherited Constants | |||||||||||
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From interface
android.database.Cursor
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Inherited Fields | |||||||||||
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From class
android.database.AbstractCursor
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Public Constructors | |||||||||||
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Public Methods | |||||||||||
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Closes the Cursor, releasing all of its resources and making it completely invalid.
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Deactivates the Cursor, making all calls on it fail until
requery() is called. | |||||||||||
Returns the value of the requested column as a byte array.
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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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Returns the numbers of rows in the cursor.
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Returns the value of the requested column as a double.
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Returns the value of the requested column as a float.
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Returns the value of the requested column as an int.
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Returns the value of the requested column as a long.
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Returns the value of the requested column as a short.
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Returns the value of the requested column as a String.
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Returns data type of the given column's value.
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Returns
true if the value in the indicated column is null. | |||||||||||
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.
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Register an observer that is called when changes happen to the content backing this cursor.
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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() . | |||||||||||
Performs the query that created the cursor again, refreshing its
contents.
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Unregister an observer that has previously been registered with this
cursor via
registerContentObserver(ContentObserver) . | |||||||||||
Unregister an observer that has previously been registered with this
cursor via
registerContentObserver(ContentObserver) . |
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Inherited Methods | |||||||||||
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From class
android.database.AbstractCursor
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From class
java.lang.Object
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From interface
android.database.CrossProcessCursor
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From interface
android.database.Cursor
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From interface
java.io.Closeable
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From interface
java.lang.AutoCloseable
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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.
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.
column | the zero-based index of the target column. |
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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 numbers of rows in the cursor.
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.
column | the zero-based index of the target column. |
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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.
column | the zero-based index of the target column. |
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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.
column | the zero-based index of the target column. |
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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.
column | the zero-based index of the target column. |
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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.
column | the zero-based index of the target column. |
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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.
column | the zero-based index of the target column. |
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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
column | the zero-based index of the target column. |
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Returns true
if the value in the indicated column is null.
column | the zero-based index of the target column. |
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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.
oldPosition | the position that we're moving from |
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newPosition | the position that we're moving to |
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.
observer | the object that gets notified when the content backing the cursor changes. |
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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()
.
observer | the object that gets notified when the cursors data set changes. |
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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.
Unregister an observer that has previously been registered with this
cursor via registerContentObserver(ContentObserver)
.
observer | the object to unregister. |
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Unregister an observer that has previously been registered with this
cursor via registerContentObserver(ContentObserver)
.
observer | the object to unregister. |
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