Somehow my UriMatcher is not working properly and because of that I am
not able to do the CRUD operations on my tables.
I have the following structure of packages and classes:
com.arpit.provider : This has a class MyContentProvider which extends
ContentProvider class
com.arpit.tables :
DatabaseHelper extends SQLiteOpenHelper
KeyTable implements BaseColumns
ParticipantTable implements BaseColumns
Now in MyContentProvider, I have done the following:
...
public static final String AUTHORITY =
"com.arpit.provider.MyContentProvider";
...
static{
UriMatcher uriM = new UriMatcher(UriMatcher.NO_MATCH);
uriM.addUri(AUTHORITY, "key", 0);
uriM.addUri(AUTHORITY, "participant", 1);
}
...
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
switch(uriM.match(uri)){
case 0:
qb.setTables("key");
break;
case 1:
qb.setTables("participant");
break;
}
....
}
...
In my KeyTable class, CONTENT_URI = "content://" +
MyContentProvider.AUTHORITY + "/key";
In my ParticipantTable class CONTENT_URI = "content://" +
MyContentProvider.AUTHORITY + "/participant";
In my AndroidManifest.xml file I have registered the provider as:
<provider android:name="com.arpit.providers.MyContentProvider"
android:authorities="com.arpit.providers.MyContentProvider"></
provider>
Now I make the query call with the following statement in my
HomeActivity:
Cursor cursor = getContentResolver().query(KeyTable.CONTENT_URI, new
String[] { KeyTable.col1 }, "_id='1'", null, null);
My problem is when the Query Method is called and the Switch block is
executed the uriM.match returns always -1 (irrespective of whether it
is KeyTable.CONTENT_URI or ParticipantTable.CONTENT_URI).
Could you let me know what wrong am I doing because of which it is not
working.
>From the note pad example I see during debug the only difference is
they call managedQuery instead of getContentReslover().query(...). I
tried firing managedQuery(...) in my HomeActivity class, but that also
result in uriM.match(uri) to return -1.
It will be great if you could help me out.
Thanks & Regards,
Arpit
On Aug 25, 10:20 pm, "A. Elk" <[email protected]> wrote:
> The Note Pad example is pretty good for URI content matching.
>
> Basically, you define one or more URIs for a ContentProvider. Don't
> think of them as "URLs", just think of them as strings with a
> particular format. Using web domains in them is a easy, nearly
> foolproof way to ensure that each URI is unique. For example, I can
> safely use the content URI content://database.lancaster.dambusters.gmail.com
> because that's my unique GMail address.
>
> Patterns come in when you want a ContentProvider to return different
> things depending on the exact URI. In the Note Pad sample (*not* the
> tutorial), there are 3 patterns corresponding to 3 "forms" of data: a
> list of notes, a single note, or a set of notes compatible with the
> LiveFolder widget. The "list of notes" form is set up in the code and
> the manifest so that it returns a set of records. The single note
> returns exactly one note, and I forget offhand what LiveFolders does.
> Let's look at the first two.
>
> For set of notes, you just specify a "base" URI. The Provider returns
> all the notes in the database that match your criteria.
>
> For a single note, you specify a pattern that is the "single note"
> base URI with a note ID number appended to it. The ID number is the
> value of the "_ID" column for the record you want. The Provider
> returns that particular note. As written, the Provider can also filter
> the note by selection criteria.
>
> If you look in the code for the Provider, you'll see that it defines
> aUriMatcher. You useUriMatcher.addUri() to match an "authority" (a
> base URI without a specific pattern) and a pattern to a value. When a
> URI comes in to the query() method, you useUriMatcher.match to match
> the incoming URI to a pattern. The method returns the value that you
> associated with the pattern in addUri(). TheUriMatcheris defined in
> a static block at the end of the code.
>
> As a note, you can use "?" in a pattern as a wildcard to match any
> string, and "#" to match any number. The "#" is used to match a single
> note in Note Pad.
>
> The Note Pad code is hard to understand because it's designed to
> accept alternate actions. This allows other apps to access the
> ContentProvider by specifying the proper authority and MimeType. You
> can ignore this, basically. The mime type tells the calling app what
> it's gonna get back from the Provider. If the type is
> vnd.android.cursor.dir, then the calling app knows it may get back
> more than one row, whereas if it gets back cursor.item, it gets back
> only one item. Incoming Intents have to specify a mimeType so that
> they exactly match Note Pad's intent filters. For example, an app that
> sends an Intent with action.GET_CONTENT but mime type
> vnd.android.cursor.dir won't match any of Note Pad's intent filters.
>
> The elkmeister.
>
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