core/java/android/widget/SimpleCursorAdapter.java - platform/frameworks/base - Git at Google

 /*
  * Copyright (C) 2006 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package android.widget;

 import android.content.Context;
 import android.database.Cursor;
 import android.net.Uri;
 import android.view.View;

 /**
  * An easy adapter to map columns from a cursor to TextViews or ImageViews
  * defined in an XML file. You can specify which columns you want, which
  * views you want to display the columns, and the XML file that defines
  * the appearance of these views.
  *
  * Binding occurs in two phases. First, if a
  * {@link android.widget.SimpleCursorAdapter.ViewBinder} is available,
  * {@link ViewBinder#setViewValue(android.view.View, android.database.Cursor, int)}
  * is invoked. If the returned value is true, binding has occured. If the
  * returned value is false and the view to bind is a TextView,
  * {@link #setViewText(TextView, String)} is invoked. If the returned value
  * is false and the view to bind is an ImageView,
  * {@link #setViewImage(ImageView, String)} is invoked. If no appropriate
  * binding can be found, an {@link IllegalStateException} is thrown.
  *
  * If this adapter is used with filtering, for instance in an
  * {@link android.widget.AutoCompleteTextView}, you can use the
  * {@link android.widget.SimpleCursorAdapter.CursorToStringConverter} and the
  * {@link android.widget.FilterQueryProvider} interfaces
  * to get control over the filtering process. You can refer to
  * {@link #convertToString(android.database.Cursor)} and
  * {@link #runQueryOnBackgroundThread(CharSequence)} for more information.
  */
 public class SimpleCursorAdapter extends ResourceCursorAdapter {
     /**
      * A list of columns containing the data to bind to the UI.
      * This field should be made private, so it is hidden from the SDK.
      * {@hide}
      */
     protected int[] mFrom;
     /**
      * A list of View ids representing the views to which the data must be bound.
      * This field should be made private, so it is hidden from the SDK.
      * {@hide}
      */
     protected int[] mTo;

     private int mStringConversionColumn = -1;
     private CursorToStringConverter mCursorToStringConverter;
     private ViewBinder mViewBinder;

     String[] mOriginalFrom;

     /**
      * Constructor the enables auto-requery.
      *
      * @deprecated This option is discouraged, as it results in Cursor queries
      * being performed on the application's UI thread and thus can cause poor
      * responsiveness or even Application Not Responding errors.  As an alternative,
      * use {@link android.app.LoaderManager} with a {@link android.content.CursorLoader}.
      */
     @Deprecated
     public SimpleCursorAdapter(Context context, int layout, Cursor c, String[] from, int[] to) {
         super(context, layout, c);
         mTo = to;
         mOriginalFrom = from;
         findColumns(c, from);
     }

     /**
      * Standard constructor.
      *
      * @param context The context where the ListView associated with this
      *            SimpleListItemFactory is running
      * @param layout resource identifier of a layout file that defines the views
      *            for this list item. The layout file should include at least
      *            those named views defined in "to"
      * @param c The database cursor.  Can be null if the cursor is not available yet.
      * @param from A list of column names representing the data to bind to the UI.  Can be null
      *            if the cursor is not available yet.
      * @param to The views that should display column in the "from" parameter.
      *            These should all be TextViews. The first N views in this list
      *            are given the values of the first N columns in the from
      *            parameter.  Can be null if the cursor is not available yet.
      * @param flags Flags used to determine the behavior of the adapter,
      * as per {@link CursorAdapter#CursorAdapter(Context, Cursor, int)}.
      */
     public SimpleCursorAdapter(Context context, int layout, Cursor c, String[] from,
             int[] to, int flags) {
         super(context, layout, c, flags);
         mTo = to;
         mOriginalFrom = from;
         findColumns(c, from);
     }

     /**
      * Binds all of the field names passed into the "to" parameter of the
      * constructor with their corresponding cursor columns as specified in the
      * "from" parameter.
      *
      * Binding occurs in two phases. First, if a
      * {@link android.widget.SimpleCursorAdapter.ViewBinder} is available,
      * {@link ViewBinder#setViewValue(android.view.View, android.database.Cursor, int)}
      * is invoked. If the returned value is true, binding has occured. If the
      * returned value is false and the view to bind is a TextView,
      * {@link #setViewText(TextView, String)} is invoked. If the returned value is
      * false and the view to bind is an ImageView,
      * {@link #setViewImage(ImageView, String)} is invoked. If no appropriate
      * binding can be found, an {@link IllegalStateException} is thrown.
      *
      * @throws IllegalStateException if binding cannot occur
      *
      * @see android.widget.CursorAdapter#bindView(android.view.View,
      *      android.content.Context, android.database.Cursor)
      * @see #getViewBinder()
      * @see #setViewBinder(android.widget.SimpleCursorAdapter.ViewBinder)
      * @see #setViewImage(ImageView, String)
      * @see #setViewText(TextView, String)
      */
     @Override
     public void bindView(View view, Context context, Cursor cursor) {
         final ViewBinder binder = mViewBinder;
         final int count = mTo.length;
         final int[] from = mFrom;
         final int[] to = mTo;

         for (int i = 0; i < count; i++) {
             final View v = view.findViewById(to[i]);
             if (v != null) {
                 boolean bound = false;
                 if (binder != null) {
                     bound = binder.setViewValue(v, cursor, from[i]);
                 }

                 if (!bound) {
                     String text = cursor.getString(from[i]);
                     if (text == null) {
                         text = "";
                     }

                     if (v instanceof TextView) {
                         setViewText((TextView) v, text);
                     } else if (v instanceof ImageView) {
                         setViewImage((ImageView) v, text);
                     } else {
                         throw new IllegalStateException(v.getClass().getName() + " is not a " +
                                 " view that can be bounds by this SimpleCursorAdapter");
                     }
                 }
             }
         }
     }

     /**
      * Returns the {@link ViewBinder} used to bind data to views.
      *
      * @return a ViewBinder or null if the binder does not exist
      *
      * @see #bindView(android.view.View, android.content.Context, android.database.Cursor)
      * @see #setViewBinder(android.widget.SimpleCursorAdapter.ViewBinder)
      */
     public ViewBinder getViewBinder() {
         return mViewBinder;
     }

     /**
      * Sets the binder used to bind data to views.
      *
      * @param viewBinder the binder used to bind data to views, can be null to
      *        remove the existing binder
      *
      * @see #bindView(android.view.View, android.content.Context, android.database.Cursor)
      * @see #getViewBinder()
      */
     public void setViewBinder(ViewBinder viewBinder) {
         mViewBinder = viewBinder;
     }

     /**
      * Called by bindView() to set the image for an ImageView but only if
      * there is no existing ViewBinder or if the existing ViewBinder cannot
      * handle binding to an ImageView.
      *
      * By default, the value will be treated as an image resource. If the
      * value cannot be used as an image resource, the value is used as an
      * image Uri.
      *
      * Intended to be overridden by Adapters that need to filter strings
      * retrieved from the database.
      *
      * @param v ImageView to receive an image
      * @param value the value retrieved from the cursor
      */
     public void setViewImage(ImageView v, String value) {
         try {
             v.setImageResource(Integer.parseInt(value));
         } catch (NumberFormatException nfe) {
             v.setImageURI(Uri.parse(value));
         }
     }

     /**
      * Called by bindView() to set the text for a TextView but only if
      * there is no existing ViewBinder or if the existing ViewBinder cannot
      * handle binding to a TextView.
      *
      * Intended to be overridden by Adapters that need to filter strings
      * retrieved from the database.
      *
      * @param v TextView to receive text
      * @param text the text to be set for the TextView
      */
     public void setViewText(TextView v, String text) {
         v.setText(text);
     }

     /**
      * Return the index of the column used to get a String representation
      * of the Cursor.
      *
      * @return a valid index in the current Cursor or -1
      *
      * @see android.widget.CursorAdapter#convertToString(android.database.Cursor)
      * @see #setStringConversionColumn(int)
      * @see #setCursorToStringConverter(android.widget.SimpleCursorAdapter.CursorToStringConverter)
      * @see #getCursorToStringConverter()
      */
     public int getStringConversionColumn() {
         return mStringConversionColumn;
     }

     /**
      * Defines the index of the column in the Cursor used to get a String
      * representation of that Cursor. The column is used to convert the
      * Cursor to a String only when the current CursorToStringConverter
      * is null.
      *
      * @param stringConversionColumn a valid index in the current Cursor or -1 to use the default
      *        conversion mechanism
      *
      * @see android.widget.CursorAdapter#convertToString(android.database.Cursor)
      * @see #getStringConversionColumn()
      * @see #setCursorToStringConverter(android.widget.SimpleCursorAdapter.CursorToStringConverter)
      * @see #getCursorToStringConverter()
      */
     public void setStringConversionColumn(int stringConversionColumn) {
         mStringConversionColumn = stringConversionColumn;
     }

     /**
      * Returns the converter used to convert the filtering Cursor
      * into a String.
      *
      * @return null if the converter does not exist or an instance of
      *         {@link android.widget.SimpleCursorAdapter.CursorToStringConverter}
      *
      * @see #setCursorToStringConverter(android.widget.SimpleCursorAdapter.CursorToStringConverter)
      * @see #getStringConversionColumn()
      * @see #setStringConversionColumn(int)
      * @see android.widget.CursorAdapter#convertToString(android.database.Cursor)
      */
     public CursorToStringConverter getCursorToStringConverter() {
         return mCursorToStringConverter;
     }

     /**
      * Sets the converter  used to convert the filtering Cursor
      * into a String.
      *
      * @param cursorToStringConverter the Cursor to String converter, or
      *        null to remove the converter
      *
      * @see #setCursorToStringConverter(android.widget.SimpleCursorAdapter.CursorToStringConverter)
      * @see #getStringConversionColumn()
      * @see #setStringConversionColumn(int)
      * @see android.widget.CursorAdapter#convertToString(android.database.Cursor)
      */
     public void setCursorToStringConverter(CursorToStringConverter cursorToStringConverter) {
         mCursorToStringConverter = cursorToStringConverter;
     }

     /**
      * Returns a CharSequence representation of the specified Cursor as defined
      * by the current CursorToStringConverter. If no CursorToStringConverter
      * has been set, the String conversion column is used instead. If the
      * conversion column is -1, the returned String is empty if the cursor
      * is null or Cursor.toString().
      *
      * @param cursor the Cursor to convert to a CharSequence
      *
      * @return a non-null CharSequence representing the cursor
      */
     @Override
     public CharSequence convertToString(Cursor cursor) {
         if (mCursorToStringConverter != null) {
             return mCursorToStringConverter.convertToString(cursor);
         } else if (mStringConversionColumn > -1) {
             return cursor.getString(mStringConversionColumn);
         }

         return super.convertToString(cursor);
     }

     /**
      * Create a map from an array of strings to an array of column-id integers in cursor c.
      * If c is null, the array will be discarded.
      *
      * @param c the cursor to find the columns from
      * @param from the Strings naming the columns of interest
      */
     private void findColumns(Cursor c, String[] from) {
         if (c != null) {
             int i;
             int count = from.length;
             if (mFrom == null || mFrom.length != count) {
                 mFrom = new int[count];
             }
             for (i = 0; i < count; i++) {
                 mFrom[i] = c.getColumnIndexOrThrow(from[i]);
             }
         } else {
             mFrom = null;
         }
     }

     @Override
     public Cursor swapCursor(Cursor c) {
         // super.swapCursor() will notify observers before we have
         // a valid mapping, make sure we have a mapping before this
         // happens
         findColumns(c, mOriginalFrom);
         return super.swapCursor(c);
     }

     /**
      * Change the cursor and change the column-to-view mappings at the same time.
      *
      * @param c The database cursor.  Can be null if the cursor is not available yet.
      * @param from A list of column names representing the data to bind to the UI.  Can be null
      *            if the cursor is not available yet.
      * @param to The views that should display column in the "from" parameter.
      *            These should all be TextViews. The first N views in this list
      *            are given the values of the first N columns in the from
      *            parameter.  Can be null if the cursor is not available yet.
      */
     public void changeCursorAndColumns(Cursor c, String[] from, int[] to) {
         mOriginalFrom = from;
         mTo = to;
         // super.changeCursor() will notify observers before we have
         // a valid mapping, make sure we have a mapping before this
         // happens
         findColumns(c, mOriginalFrom);
         super.changeCursor(c);
     }

     /**
      * This class can be used by external clients of SimpleCursorAdapter
      * to bind values fom the Cursor to views.
      *
      * You should use this class to bind values from the Cursor to views
      * that are not directly supported by SimpleCursorAdapter or to
      * change the way binding occurs for views supported by
      * SimpleCursorAdapter.
      *
      * @see SimpleCursorAdapter#bindView(android.view.View, android.content.Context, android.database.Cursor)
      * @see SimpleCursorAdapter#setViewImage(ImageView, String)
      * @see SimpleCursorAdapter#setViewText(TextView, String)
      */
     public static interface ViewBinder {
         /**
          * Binds the Cursor column defined by the specified index to the specified view.
          *
          * When binding is handled by this ViewBinder, this method must return true.
          * If this method returns false, SimpleCursorAdapter will attempts to handle
          * the binding on its own.
          *
          * @param view the view to bind the data to
          * @param cursor the cursor to get the data from
          * @param columnIndex the column at which the data can be found in the cursor
          *
          * @return true if the data was bound to the view, false otherwise
          */
         boolean setViewValue(View view, Cursor cursor, int columnIndex);
     }

     /**
      * This class can be used by external clients of SimpleCursorAdapter
      * to define how the Cursor should be converted to a String.
      *
      * @see android.widget.CursorAdapter#convertToString(android.database.Cursor)
      */
     public static interface CursorToStringConverter {
         /**
          * Returns a CharSequence representing the specified Cursor.
          *
          * @param cursor the cursor for which a CharSequence representation
          *        is requested
          *
          * @return a non-null CharSequence representing the cursor
          */
         CharSequence convertToString(Cursor cursor);
     }

 }
	/*
	* Copyright (C) 2006 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package android.widget;

	import android.content.Context;
	import android.database.Cursor;
	import android.net.Uri;
	import android.view.View;

	/**
	* An easy adapter to map columns from a cursor to TextViews or ImageViews
	* defined in an XML file. You can specify which columns you want, which
	* views you want to display the columns, and the XML file that defines
	* the appearance of these views.
	*
	* Binding occurs in two phases. First, if a
	* {@link android.widget.SimpleCursorAdapter.ViewBinder} is available,
	* {@link ViewBinder#setViewValue(android.view.View, android.database.Cursor, int)}
	* is invoked. If the returned value is true, binding has occured. If the
	* returned value is false and the view to bind is a TextView,
	* {@link #setViewText(TextView, String)} is invoked. If the returned value
	* is false and the view to bind is an ImageView,
	* {@link #setViewImage(ImageView, String)} is invoked. If no appropriate
	* binding can be found, an {@link IllegalStateException} is thrown.
	*
	* If this adapter is used with filtering, for instance in an
	* {@link android.widget.AutoCompleteTextView}, you can use the
	* {@link android.widget.SimpleCursorAdapter.CursorToStringConverter} and the
	* {@link android.widget.FilterQueryProvider} interfaces
	* to get control over the filtering process. You can refer to
	* {@link #convertToString(android.database.Cursor)} and
	* {@link #runQueryOnBackgroundThread(CharSequence)} for more information.
	*/
	public class SimpleCursorAdapter extends ResourceCursorAdapter {
	/**
	* A list of columns containing the data to bind to the UI.
	* This field should be made private, so it is hidden from the SDK.
	* {@hide}
	*/
	protected int[] mFrom;
	/**
	* A list of View ids representing the views to which the data must be bound.
	* This field should be made private, so it is hidden from the SDK.
	* {@hide}
	*/
	protected int[] mTo;

	private int mStringConversionColumn = -1;
	private CursorToStringConverter mCursorToStringConverter;
	private ViewBinder mViewBinder;

	String[] mOriginalFrom;

	/**
	* Constructor the enables auto-requery.
	*
	* @deprecated This option is discouraged, as it results in Cursor queries
	* being performed on the application's UI thread and thus can cause poor
	* responsiveness or even Application Not Responding errors. As an alternative,
	* use {@link android.app.LoaderManager} with a {@link android.content.CursorLoader}.
	*/
	@Deprecated
	public SimpleCursorAdapter(Context context, int layout, Cursor c, String[] from, int[] to) {
	super(context, layout, c);
	mTo = to;
	mOriginalFrom = from;
	findColumns(c, from);
	}

	/**
	* Standard constructor.
	*
	* @param context The context where the ListView associated with this
	* SimpleListItemFactory is running
	* @param layout resource identifier of a layout file that defines the views
	* for this list item. The layout file should include at least
	* those named views defined in "to"
	* @param c The database cursor. Can be null if the cursor is not available yet.
	* @param from A list of column names representing the data to bind to the UI. Can be null
	* if the cursor is not available yet.
	* @param to The views that should display column in the "from" parameter.
	* These should all be TextViews. The first N views in this list
	* are given the values of the first N columns in the from
	* parameter. Can be null if the cursor is not available yet.
	* @param flags Flags used to determine the behavior of the adapter,
	* as per {@link CursorAdapter#CursorAdapter(Context, Cursor, int)}.
	*/
	public SimpleCursorAdapter(Context context, int layout, Cursor c, String[] from,
	int[] to, int flags) {
	super(context, layout, c, flags);
	mTo = to;
	mOriginalFrom = from;
	findColumns(c, from);
	}

	/**
	* Binds all of the field names passed into the "to" parameter of the
	* constructor with their corresponding cursor columns as specified in the
	* "from" parameter.
	*
	* Binding occurs in two phases. First, if a
	* {@link android.widget.SimpleCursorAdapter.ViewBinder} is available,
	* {@link ViewBinder#setViewValue(android.view.View, android.database.Cursor, int)}
	* is invoked. If the returned value is true, binding has occured. If the
	* returned value is false and the view to bind is a TextView,
	* {@link #setViewText(TextView, String)} is invoked. If the returned value is
	* false and the view to bind is an ImageView,
	* {@link #setViewImage(ImageView, String)} is invoked. If no appropriate
	* binding can be found, an {@link IllegalStateException} is thrown.
	*
	* @throws IllegalStateException if binding cannot occur
	*
	* @see android.widget.CursorAdapter#bindView(android.view.View,
	* android.content.Context, android.database.Cursor)
	* @see #getViewBinder()
	* @see #setViewBinder(android.widget.SimpleCursorAdapter.ViewBinder)
	* @see #setViewImage(ImageView, String)
	* @see #setViewText(TextView, String)
	*/
	@Override
	public void bindView(View view, Context context, Cursor cursor) {
	final ViewBinder binder = mViewBinder;
	final int count = mTo.length;
	final int[] from = mFrom;
	final int[] to = mTo;

	for (int i = 0; i < count; i++) {
	final View v = view.findViewById(to[i]);
	if (v != null) {
	boolean bound = false;
	if (binder != null) {
	bound = binder.setViewValue(v, cursor, from[i]);
	}

	if (!bound) {
	String text = cursor.getString(from[i]);
	if (text == null) {
	text = "";
	}

	if (v instanceof TextView) {
	setViewText((TextView) v, text);
	} else if (v instanceof ImageView) {
	setViewImage((ImageView) v, text);
	} else {
	throw new IllegalStateException(v.getClass().getName() + " is not a " +
	" view that can be bounds by this SimpleCursorAdapter");
	}
	}
	}
	}
	}

	/**
	* Returns the {@link ViewBinder} used to bind data to views.
	*
	* @return a ViewBinder or null if the binder does not exist
	*
	* @see #bindView(android.view.View, android.content.Context, android.database.Cursor)
	* @see #setViewBinder(android.widget.SimpleCursorAdapter.ViewBinder)
	*/
	public ViewBinder getViewBinder() {
	return mViewBinder;
	}

	/**
	* Sets the binder used to bind data to views.
	*
	* @param viewBinder the binder used to bind data to views, can be null to
	* remove the existing binder
	*
	* @see #bindView(android.view.View, android.content.Context, android.database.Cursor)
	* @see #getViewBinder()
	*/
	public void setViewBinder(ViewBinder viewBinder) {
	mViewBinder = viewBinder;
	}

	/**
	* Called by bindView() to set the image for an ImageView but only if
	* there is no existing ViewBinder or if the existing ViewBinder cannot
	* handle binding to an ImageView.
	*
	* By default, the value will be treated as an image resource. If the
	* value cannot be used as an image resource, the value is used as an
	* image Uri.
	*
	* Intended to be overridden by Adapters that need to filter strings
	* retrieved from the database.
	*
	* @param v ImageView to receive an image
	* @param value the value retrieved from the cursor
	*/
	public void setViewImage(ImageView v, String value) {
	try {
	v.setImageResource(Integer.parseInt(value));
	} catch (NumberFormatException nfe) {
	v.setImageURI(Uri.parse(value));
	}
	}

	/**
	* Called by bindView() to set the text for a TextView but only if
	* there is no existing ViewBinder or if the existing ViewBinder cannot
	* handle binding to a TextView.
	*
	* Intended to be overridden by Adapters that need to filter strings
	* retrieved from the database.
	*
	* @param v TextView to receive text
	* @param text the text to be set for the TextView
	*/
	public void setViewText(TextView v, String text) {
	v.setText(text);
	}

	/**
	* Return the index of the column used to get a String representation
	* of the Cursor.
	*
	* @return a valid index in the current Cursor or -1
	*
	* @see android.widget.CursorAdapter#convertToString(android.database.Cursor)
	* @see #setStringConversionColumn(int)
	* @see #setCursorToStringConverter(android.widget.SimpleCursorAdapter.CursorToStringConverter)
	* @see #getCursorToStringConverter()
	*/
	public int getStringConversionColumn() {
	return mStringConversionColumn;
	}

	/**
	* Defines the index of the column in the Cursor used to get a String
	* representation of that Cursor. The column is used to convert the
	* Cursor to a String only when the current CursorToStringConverter
	* is null.
	*
	* @param stringConversionColumn a valid index in the current Cursor or -1 to use the default
	* conversion mechanism
	*
	* @see android.widget.CursorAdapter#convertToString(android.database.Cursor)
	* @see #getStringConversionColumn()
	* @see #setCursorToStringConverter(android.widget.SimpleCursorAdapter.CursorToStringConverter)
	* @see #getCursorToStringConverter()
	*/
	public void setStringConversionColumn(int stringConversionColumn) {
	mStringConversionColumn = stringConversionColumn;
	}

	/**
	* Returns the converter used to convert the filtering Cursor
	* into a String.
	*
	* @return null if the converter does not exist or an instance of
	* {@link android.widget.SimpleCursorAdapter.CursorToStringConverter}
	*
	* @see #setCursorToStringConverter(android.widget.SimpleCursorAdapter.CursorToStringConverter)
	* @see #getStringConversionColumn()
	* @see #setStringConversionColumn(int)
	* @see android.widget.CursorAdapter#convertToString(android.database.Cursor)
	*/
	public CursorToStringConverter getCursorToStringConverter() {
	return mCursorToStringConverter;
	}

	/**
	* Sets the converter used to convert the filtering Cursor
	* into a String.
	*
	* @param cursorToStringConverter the Cursor to String converter, or
	* null to remove the converter
	*
	* @see #setCursorToStringConverter(android.widget.SimpleCursorAdapter.CursorToStringConverter)
	* @see #getStringConversionColumn()
	* @see #setStringConversionColumn(int)
	* @see android.widget.CursorAdapter#convertToString(android.database.Cursor)
	*/
	public void setCursorToStringConverter(CursorToStringConverter cursorToStringConverter) {
	mCursorToStringConverter = cursorToStringConverter;
	}

	/**
	* Returns a CharSequence representation of the specified Cursor as defined
	* by the current CursorToStringConverter. If no CursorToStringConverter
	* has been set, the String conversion column is used instead. If the
	* conversion column is -1, the returned String is empty if the cursor
	* is null or Cursor.toString().
	*
	* @param cursor the Cursor to convert to a CharSequence
	*
	* @return a non-null CharSequence representing the cursor
	*/
	@Override
	public CharSequence convertToString(Cursor cursor) {
	if (mCursorToStringConverter != null) {
	return mCursorToStringConverter.convertToString(cursor);
	} else if (mStringConversionColumn > -1) {
	return cursor.getString(mStringConversionColumn);
	}

	return super.convertToString(cursor);
	}

	/**
	* Create a map from an array of strings to an array of column-id integers in cursor c.
	* If c is null, the array will be discarded.
	*
	* @param c the cursor to find the columns from
	* @param from the Strings naming the columns of interest
	*/
	private void findColumns(Cursor c, String[] from) {
	if (c != null) {
	int i;
	int count = from.length;
	if (mFrom == null \|\| mFrom.length != count) {
	mFrom = new int[count];
	}
	for (i = 0; i < count; i++) {
	mFrom[i] = c.getColumnIndexOrThrow(from[i]);
	}
	} else {
	mFrom = null;
	}
	}

	@Override
	public Cursor swapCursor(Cursor c) {
	// super.swapCursor() will notify observers before we have
	// a valid mapping, make sure we have a mapping before this
	// happens
	findColumns(c, mOriginalFrom);
	return super.swapCursor(c);
	}

	/**
	* Change the cursor and change the column-to-view mappings at the same time.
	*
	* @param c The database cursor. Can be null if the cursor is not available yet.
	* @param from A list of column names representing the data to bind to the UI. Can be null
	* if the cursor is not available yet.
	* @param to The views that should display column in the "from" parameter.
	* These should all be TextViews. The first N views in this list
	* are given the values of the first N columns in the from
	* parameter. Can be null if the cursor is not available yet.
	*/
	public void changeCursorAndColumns(Cursor c, String[] from, int[] to) {
	mOriginalFrom = from;
	mTo = to;
	// super.changeCursor() will notify observers before we have
	// a valid mapping, make sure we have a mapping before this
	// happens
	findColumns(c, mOriginalFrom);
	super.changeCursor(c);
	}

	/**
	* This class can be used by external clients of SimpleCursorAdapter
	* to bind values fom the Cursor to views.
	*
	* You should use this class to bind values from the Cursor to views
	* that are not directly supported by SimpleCursorAdapter or to
	* change the way binding occurs for views supported by
	* SimpleCursorAdapter.
	*
	* @see SimpleCursorAdapter#bindView(android.view.View, android.content.Context, android.database.Cursor)
	* @see SimpleCursorAdapter#setViewImage(ImageView, String)
	* @see SimpleCursorAdapter#setViewText(TextView, String)
	*/
	public static interface ViewBinder {
	/**
	* Binds the Cursor column defined by the specified index to the specified view.
	*
	* When binding is handled by this ViewBinder, this method must return true.
	* If this method returns false, SimpleCursorAdapter will attempts to handle
	* the binding on its own.
	*
	* @param view the view to bind the data to
	* @param cursor the cursor to get the data from
	* @param columnIndex the column at which the data can be found in the cursor
	*
	* @return true if the data was bound to the view, false otherwise
	*/
	boolean setViewValue(View view, Cursor cursor, int columnIndex);
	}

	/**
	* This class can be used by external clients of SimpleCursorAdapter
	* to define how the Cursor should be converted to a String.
	*
	* @see android.widget.CursorAdapter#convertToString(android.database.Cursor)
	*/
	public static interface CursorToStringConverter {
	/**
	* Returns a CharSequence representing the specified Cursor.
	*
	* @param cursor the cursor for which a CharSequence representation
	* is requested
	*
	* @return a non-null CharSequence representing the cursor
	*/
	CharSequence convertToString(Cursor cursor);
	}

	}