Package android.database

Interface Cursor

    • Method Summary

      All Methods Instance Methods Abstract Methods Deprecated Methods 
      Modifier and Type Method Description
      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()
      Deprecated.
      Since requery() is deprecated, so too is this.
      byte[] getBlob​(int columnIndex)
      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.
      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​(int columnIndex)
      Returns the value of the requested column as a double.
      Bundle getExtras()
      Returns a bundle of extra values.
      float getFloat​(int columnIndex)
      Returns the value of the requested column as a float.
      int getInt​(int columnIndex)
      Returns the value of the requested column as an int.
      long getLong​(int columnIndex)
      Returns the value of the requested column as a long.
      int getPosition()
      Returns the current position of the cursor in the row set.
      short getShort​(int columnIndex)
      Returns the value of the requested column as a short.
      String getString​(int columnIndex)
      Returns the value of the requested column as a String.
      int getType​(int columnIndex)
      Returns data type of the given column's value.
      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​(int columnIndex)
      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.
      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 requery(), deactivate(), or close().
      boolean requery()
      Deprecated.
      Don't use this.
      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 getExtras().
      void unregisterDataSetObserver​(DataSetObserver observer)
      Unregister an observer that has previously been registered with this cursor via #registerContentObserver.

    • Method Detail

      • getCount

        int getCount()
        Returns the numbers of rows in the cursor.
        Returns:
        the number of rows in the cursor.

      • getPosition

        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().
        Returns:
        the current cursor position.

      • move

        boolean move​(int offset)
        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 - the offset to be applied from the current position.
        Returns:
        whether the requested move fully succeeded.

      • moveToPosition

        boolean moveToPosition​(int position)
        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 - the zero-based position to move to.
        Returns:
        whether the requested move fully succeeded.

      • moveToFirst

        boolean moveToFirst()
        Move the cursor to the first row.

        This method will return false if the cursor is empty.

        Returns:
        whether the move succeeded.

      • moveToLast

        boolean moveToLast()
        Move the cursor to the last row.

        This method will return false if the cursor is empty.

        Returns:
        whether the move succeeded.

      • moveToNext

        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.

        Returns:
        whether the move succeeded.

      • moveToPrevious

        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.

        Returns:
        whether the move succeeded.

      • isFirst

        boolean isFirst()
        Returns whether the cursor is pointing to the first row.
        Returns:
        whether the cursor is pointing at the first entry.

      • isLast

        boolean isLast()
        Returns whether the cursor is pointing to the last row.
        Returns:
        whether the cursor is pointing at the last entry.

      • isBeforeFirst

        boolean isBeforeFirst()
        Returns whether the cursor is pointing to the position before the first row.
        Returns:
        whether the cursor is before the first result.

      • isAfterLast

        boolean isAfterLast()
        Returns whether the cursor is pointing to the position after the last row.
        Returns:
        whether the cursor is after the last result.

      • getColumnIndex

        int getColumnIndex​(String columnName)
        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 - the name of the target column.
        Returns:
        the zero-based column index for the given column name, or -1 if the column name does not exist.
        See Also:
        getColumnIndexOrThrow(String)

      • getColumnName

        String getColumnName​(int columnIndex)
        Returns the column name at the given zero-based column index.
        Parameters:
        columnIndex - the zero-based index of the target column.
        Returns:
        the column name for the given column index.

      • getColumnNames

        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.
        Returns:
        the names of the columns returned in this query.

      • getColumnCount

        int getColumnCount()
        Return total number of columns
        Returns:
        number of columns

      • getBlob

        byte[] getBlob​(int columnIndex)
        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.
        Returns:
        the value of that column as a byte array.

      • getString

        String getString​(int columnIndex)
        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.
        Returns:
        the value of that column as a String.

      • copyStringToBuffer

        void copyStringToBuffer​(int columnIndex,
                        CharArrayBuffer buffer)
        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 - the zero-based index of the target column. if the target column is null, return buffer
        buffer - the buffer to copy the text into.

      • getShort

        short getShort​(int columnIndex)
        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.
        Returns:
        the value of that column as a short.

      • getInt

        int getInt​(int columnIndex)
        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.
        Returns:
        the value of that column as an int.

      • getLong

        long getLong​(int columnIndex)
        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.
        Returns:
        the value of that column as a long.

      • getFloat

        float getFloat​(int columnIndex)
        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 - the zero-based index of the target column.
        Returns:
        the value of that column as a float.

      • getDouble

        double getDouble​(int columnIndex)
        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.
        Returns:
        the value of that column as a double.

      • isNull

        boolean isNull​(int columnIndex)
        Returns true if the value in the indicated column is null.
        Parameters:
        columnIndex - the zero-based index of the target column.
        Returns:
        whether the column value is null.

      • deactivate

        void deactivate()
        Deprecated.
        Since requery() is deprecated, so too is this.
        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.

      • requery

        @Deprecated
boolean requery()
        Deprecated.
        Don't use this. Just request a new cursor, so you can do this asynchronously and update your list view once the new cursor comes back.
        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.
        Returns:
        true if the requery succeeded, false if not, in which case the cursor becomes invalid.

      • close

        void 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.
        Specified by:
        close in interface AutoCloseable
        Specified by:
        close in interface Closeable

      • isClosed

        boolean isClosed()
        return true if the cursor is closed
        Returns:
        true if the cursor is closed.

      • unregisterDataSetObserver

        void unregisterDataSetObserver​(DataSetObserver observer)
        Unregister an observer that has previously been registered with this cursor via #registerContentObserver.
        Parameters:
        observer - the object to unregister.
        See Also:
        registerDataSetObserver(DataSetObserver)

      • getWantsAllOnMoveCalls

        boolean getWantsAllOnMoveCalls()
        onMove() will only be called across processes if this method returns true.
        Returns:
        whether all cursor movement should result in a call to onMove().

      • setExtras

        void setExtras​(Bundle extras)
        Sets a Bundle that will be returned by getExtras().
        Parameters:
        extras - Bundle to set, or null to set an empty bundle.

      • getExtras

        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.

        Returns:
        cursor-defined values, or Bundle.EMPTY if there are no values. Never null.

      • respond

        Bundle respond​(Bundle extras)
        This is an out-of-band way for the 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 - extra values, or Bundle.EMPTY. Never null.
        Returns:
        extra values, or Bundle.EMPTY. Never null.