UriMatcher

public class UriMatcher
extends Object

java.lang.Object
   ↳ android.content.UriMatcher

Utility class to aid in matching URIs in content providers.

To use this class, build up a tree of UriMatcher objects. For example: 

    private static final int PEOPLE = 1;
    private static final int PEOPLE_ID = 2;
    private static final int PEOPLE_PHONES = 3;
    private static final int PEOPLE_PHONES_ID = 4;
    private static final int PEOPLE_CONTACTMETHODS = 7;
    private static final int PEOPLE_CONTACTMETHODS_ID = 8;

    private static final int DELETED_PEOPLE = 20;

    private static final int PHONES = 9;
    private static final int PHONES_ID = 10;
    private static final int PHONES_FILTER = 14;

    private static final int CONTACTMETHODS = 18;
    private static final int CONTACTMETHODS_ID = 19;

    private static final int CALLS = 11;
    private static final int CALLS_ID = 12;
    private static final int CALLS_FILTER = 15;

    private static final UriMatcher sURIMatcher = new UriMatcher(UriMatcher.NO_MATCH);

    static
    {
        sURIMatcher.addURI("contacts", "people", PEOPLE);
        sURIMatcher.addURI("contacts", "people/#", PEOPLE_ID);
        sURIMatcher.addURI("contacts", "people/#/phones", PEOPLE_PHONES);
        sURIMatcher.addURI("contacts", "people/#/phones/#", PEOPLE_PHONES_ID);
        sURIMatcher.addURI("contacts", "people/#/contact_methods", PEOPLE_CONTACTMETHODS);
        sURIMatcher.addURI("contacts", "people/#/contact_methods/#", PEOPLE_CONTACTMETHODS_ID);
        sURIMatcher.addURI("contacts", "deleted_people", DELETED_PEOPLE);
        sURIMatcher.addURI("contacts", "phones", PHONES);
        sURIMatcher.addURI("contacts", "phones/filter/*", PHONES_FILTER);
        sURIMatcher.addURI("contacts", "phones/#", PHONES_ID);
        sURIMatcher.addURI("contacts", "contact_methods", CONTACTMETHODS);
        sURIMatcher.addURI("contacts", "contact_methods/#", CONTACTMETHODS_ID);
        sURIMatcher.addURI("call_log", "calls", CALLS);
        sURIMatcher.addURI("call_log", "calls/filter/*", CALLS_FILTER);
        sURIMatcher.addURI("call_log", "calls/#", CALLS_ID);
    }

Starting from API level Build.VERSION_CODES.JELLY_BEAN_MR2, paths can start with a leading slash. For example: 

        sURIMatcher.addURI("contacts", "/people", PEOPLE);

Then when you need to match against a URI, call match(Uri), providing the URL that you have been given. You can use the result to build a query, return a type, insert or delete a row, or whatever you need, without duplicating all of the if-else logic that you would otherwise need. For example: 

    public String getType(Uri url)
    {
        int match = sURIMatcher.match(url);
        switch (match)
        {
            case PEOPLE:
                return "vnd.android.cursor.dir/person";
            case PEOPLE_ID:
                return "vnd.android.cursor.item/person";
 ... snip ...
                return "vnd.android.cursor.dir/snail-mail";
            case PEOPLE_ADDRESS_ID:
                return "vnd.android.cursor.item/snail-mail";
            default:
                return null;
        }
    }
instead of: 
    public String getType(Uri url)
    {
        List pathSegments = url.getPathSegments();
        if (pathSegments.size() >= 2) {
            if ("people".equals(pathSegments.get(1))) {
                if (pathSegments.size() == 2) {
                    return "vnd.android.cursor.dir/person";
                } else if (pathSegments.size() == 3) {
                    return "vnd.android.cursor.item/person";
 ... snip ...
                    return "vnd.android.cursor.dir/snail-mail";
                } else if (pathSegments.size() == 3) {
                    return "vnd.android.cursor.item/snail-mail";
                }
            }
        }
        return null;
    }

Summary

Constants

int NO_MATCH

Public constructors

UriMatcher(int code)

Creates the root node of the URI tree.

Public methods

void addURI(String authority, String path, int code)

Add a URI to match, and the code to return when this URI is matched.

int match(Uri uri)

Try to match against the path in a url.

Inherited methods

Constants

NO_MATCH

Added in API level 1 
public static final int NO_MATCH

Constant Value: -1 (0xffffffff)

Public constructors

UriMatcher

Added in API level 1 
public UriMatcher (int code)

Creates the root node of the URI tree.

Parameters
code int: the code to match for the root URI

Public methods

addURI

Added in API level 1 
public void addURI (String authority, 
                String path, 
                int code)

Add a URI to match, and the code to return when this URI is matched. URI nodes may be exact match string, the token "*" that matches any text, or the token "#" that matches only numbers.

Starting from API level Build.VERSION_CODES.JELLY_BEAN_MR2, this method will accept a leading slash in the path.

Parameters
authority String: the authority to match
path String: the path to match. * may be used as a wild card for any text, and # may be used as a wild card for numbers.
code int: the code that is returned when a URI is matched against the given components. Must be positive.

match

Added in API level 1 
public int match (Uri uri)

Try to match against the path in a url.

Parameters
uri Uri: The url whose path we will match against.
Returns
int The code for the matched node (added using addURI), or -1 if there is no matched node.