Android Tutorial

Android Tutorial 353

The Uri is first validated to make sure it’s one where inserting

makes sense. A Uri targeting a particular row would not, for

instance. Next, a writeable database object instance is retrieved.

Using this, the database insert() method is called on the table

defined by the incoming Uri and with the values passed in. At this

point, no error checking is performed on the values. Instead, the

underlying database implementation throws exceptions that can be

handled by the user of the content provider.

If the insert was successful, a Uri is created for notifying the

system of a change to the underlying data via a call to the

notifyChange() method of the Content Resolver. Otherwise, an

exception is thrown.

Implementing the update() Method

The update() method is used to modify an existing row of data. It

has elements similar to the insert() and query() methods. The

update is applied to a particular selection defined by the incoming

Uri.

public int update(Uri uri, ContentValues values,
String selection, String[] selectionArgs) {
SQLiteDatabase sqlDB = mDB.getWritableDatabase();
int match = sURIMatcher.match(uri);
int rowsAffected;
switch (match) {
case TRACKPOINTS:
rowsAffected = sqlDB.update(
TrackPointDatabase.TRACKPOINTS_TABLE,
values, selection, selectionArgs);
break;
case TRACKPOINT_ID:
String id = uri.getLastPathSegment();
if (TextUtils.isEmpty(selection)) {