Android
android.database
public class

android.database.MergeCursor

java.lang.Object
android.database.AbstractCursor CrossProcessCursor
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.

Summary

Fields inherited from class android.database.AbstractCursor

Public Constructors

            MergeCursor(Cursor[] cursors)

Public Methods

          void  close()
Closes the Cursor, releasing all of its resources and making it completely invalid.
          void  deactivate()
Deactivates the Cursor, making all calls on it fail until requery() is called.
          byte[]  getBlob(int column)
Returns the value of the requested column as a byte 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(int column)
Returns the value of the requested column as a double.
          float  getFloat(int column)
Returns the value of the requested column as a float.
          int  getInt(int column)
Returns the value of the requested column as an int.
          long  getLong(int column)
Returns the value of the requested column as a long.
          short  getShort(int column)
Returns the value of the requested column as a short.
          String  getString(int column)
Returns the value of the requested column as a String.
          boolean  isNull(int column)
Returns true if the value in the indicated column is null.
          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 requery(), deactivate(), or close().
          boolean  requery()
Performs the query that created the cursor again, refreshing its contents.
          void  unregisterContentObserver(ContentObserver observer)
Unregister an observer that has previously been registered with this cursor via registerContentObserver(ContentObserver).
          void  unregisterDataSetObserver(DataSetObserver observer)
Unregister an observer that has previously been registered with this cursor via registerContentObserver(ContentObserver).
Methods inherited from class android.database.AbstractCursor
Methods inherited from class java.lang.Object
Methods inherited from interface android.database.CrossProcessCursor
Methods inherited from interface android.database.Cursor

Details

Public Constructors

public MergeCursor(Cursor[] cursors)

Public Methods

public 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.

public void 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.

public byte[] getBlob(int column)

Returns the value of the requested column as a byte array.

If the native content of that column is not blob exception may throw

public 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.

public int getCount()

Returns the numbers of rows in the cursor.

public double getDouble(int column)

Returns the value of the requested column as a double.

If the native content of that column is not numeric the result will be the result of passing the column value to Double.valueOf(x).

public float getFloat(int column)

Returns the value of the requested column as a float.

If the native content of that column is not numeric the result will be the result of passing the column value to Float.valueOf(x).

public int getInt(int column)

Returns the value of the requested column as an int.

If the native content of that column is not numeric the result will be the result of passing the column value to Integer.valueOf(x).

public long getLong(int column)

Returns the value of the requested column as a long.

If the native content of that column is not numeric the result will be the result of passing the column value to Long.valueOf(x).

public short getShort(int column)

Returns the value of the requested column as a short.

If the native content of that column is not numeric the result will be the result of passing the column value to Short.valueOf(x).

public String getString(int column)

Returns the value of the requested column as a String.

If the native content of that column is not text the result will be the result of passing the column value to String.valueOf(x).

public boolean isNull(int column)

Returns true if the value in the indicated column is null.

public 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. If it returns false the move function will also do so and the cursor will scroll to the beforeFirst position.

Parameters

oldPosition the position that we're moving from
newPosition the position that we're moving to

Returns

  • true if the move is successful, false otherwise

public void registerContentObserver(ContentObserver observer)

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.

public 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().

public 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().

public void unregisterContentObserver(ContentObserver observer)

Unregister an observer that has previously been registered with this cursor via registerContentObserver(ContentObserver).

public void unregisterDataSetObserver(DataSetObserver observer)

Unregister an observer that has previously been registered with this cursor via registerContentObserver(ContentObserver).
Copyright 2007 Google Inc. Build 0.9_r1-98467 - 14 Aug 2008 18:56