The cursor and its adapter mode

1.public Interface Cursor

|-android.database.cursor

The cursor is generally used to store the collection of query results , especially the return value of the database's query method is the cursor object, and the cursor object holds the result of the query. Similar to iterator iterators.

Common methods:

Movetofirst ();//This method causes cursor cursors to point to the first row of the data record, which is used to iterate from the first line

MoveToNext ();//Determine if the next row has a record, and then point to the next line.

Xxxx getxxxx(int columnindex);//Based on columnindex, gets the value of XXX data type,

int Getcolumnindexorthrow (String columnName)//gets its index value based on the column name

Note: You can use the activity's Startmanagingcursor (cursor) method to manage the life cycle of the created cursor so that it is easy to reclaim and destroy the cursor.

Case:

XXXX getxxxx (Getcolumnindexorthrow (String columnName));//based on the column name, gets the value (XXXX) on the column name on the table;

Traverse:

Cursor.movetofirst ()

while (Cursor.movetonext ())

{

Cursor.xxx ();//Traversal result set

}

2.public Abstract class CursorAdapter

Extends Baseadapter
Implements Filterable

Subclass is the following two sub-classes

When implementing CursorAdapter, you implement the following abstract methods:

     //Create a new View object@Override PublicView Newview (context context, cursor cursor, viewgroup parent) {View View=Super. Newview (context, cursor, parent); Tag Tag=NewTag (); Tag.icon=(ImageView) View.findviewbyid (R.id.book_icon); Tag.author=(TextView) View.findviewbyid (R.id.author); Tag.name=(TextView) View.findviewbyid (r.id.book_name); Tag.year=(TextView) View.findviewbyid (r.id.year);            View.settag (tag); returnview; }      //bind the data that the cursor points to and the View object that is created@Override Public voidBindView (view view, context context, cursor cursor) {tag tag=(TAG) View.gettag ();            Tag.author.setText (cursor.getstring (cursor. Getcolumnindexorthrow (Publisher.AUTHOR.NAME)));            Tag.name.setText (cursor.getstring (cursor. Getcolumnindexorthrow (Publisher.BOOK.NAME)));            Tag.year.setText (cursor.getstring (cursor. Getcolumnindexorthrow (Publisher.BOOK.PUBLISH_YEAR))); Bitmap icon=Bitmapfactory.decoderesource (Getresources (), R.drawable.icon);        Tag.icon.setImageBitmap (icon); }     //A collection of various UI components inside the view   classTag { PublicImageView icon;  PublicTextView name;  PublicTextView author;  PublicTextView Year; }

3.public Abstract class Resourcecursoradapter

Function: The cursor data is displayed on the view via the adapter

Resourcecursoradapter (context context, int layout, Cursor c)

4.public class Simplecursoradapter

Simplecursoradapter (context context, int layout, Cursor C, string[] from, int[] to)

The cursor and its adapter mode