Android example source code file (DictionaryProvider.java)

This example Android source code file (DictionaryProvider.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, app, authority, content, cursor, dictionarydatabase, get_word, illegalargumentexception, net, network, override, provider, refresh_shortcut, search_suggest, search_words, string, unknown, unsupportedoperationexception, uri, urimatcher

The DictionaryProvider.java Android example source code

/*
 * Copyright (C) 2010 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 com.example.android.searchabledict;

import android.app.SearchManager;
import android.content.ContentProvider;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.net.Uri;
import android.provider.BaseColumns;

/**
 * Provides access to the dictionary database.
 */
public class DictionaryProvider extends ContentProvider {
    String TAG = "DictionaryProvider";

    public static String AUTHORITY = "com.example.android.searchabledict.DictionaryProvider";
    public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/dictionary");

    // MIME types used for searching words or looking up a single definition
    public static final String WORDS_MIME_TYPE = ContentResolver.CURSOR_DIR_BASE_TYPE +
                                                  "/vnd.example.android.searchabledict";
    public static final String DEFINITION_MIME_TYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE +
                                                       "/vnd.example.android.searchabledict";

    private DictionaryDatabase mDictionary;

    // UriMatcher stuff
    private static final int SEARCH_WORDS = 0;
    private static final int GET_WORD = 1;
    private static final int SEARCH_SUGGEST = 2;
    private static final int REFRESH_SHORTCUT = 3;
    private static final UriMatcher sURIMatcher = buildUriMatcher();

    /**
     * Builds up a UriMatcher for search suggestion and shortcut refresh queries.
     */
    private static UriMatcher buildUriMatcher() {
        UriMatcher matcher =  new UriMatcher(UriMatcher.NO_MATCH);
        // to get definitions...
        matcher.addURI(AUTHORITY, "dictionary", SEARCH_WORDS);
        matcher.addURI(AUTHORITY, "dictionary/#", GET_WORD);
        // to get suggestions...
        matcher.addURI(AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY, SEARCH_SUGGEST);
        matcher.addURI(AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY + "/*", SEARCH_SUGGEST);

        /* The following are unused in this implementation, but if we include
         * {@link SearchManager#SUGGEST_COLUMN_SHORTCUT_ID} as a column in our suggestions table, we
         * could expect to receive refresh queries when a shortcutted suggestion is displayed in
         * Quick Search Box, in which case, the following Uris would be provided and we
         * would return a cursor with a single item representing the refreshed suggestion data.
         */
        matcher.addURI(AUTHORITY, SearchManager.SUGGEST_URI_PATH_SHORTCUT, REFRESH_SHORTCUT);
        matcher.addURI(AUTHORITY, SearchManager.SUGGEST_URI_PATH_SHORTCUT + "/*", REFRESH_SHORTCUT);
        return matcher;
    }

    @Override
    public boolean onCreate() {
        mDictionary = new DictionaryDatabase(getContext());
        return true;
    }

    /**
     * Handles all the dictionary searches and suggestion queries from the Search Manager.
     * When requesting a specific word, the uri alone is required.
     * When searching all of the dictionary for matches, the selectionArgs argument must carry
     * the search query as the first element.
     * All other arguments are ignored.
     */
    @Override
    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
                        String sortOrder) {

        // Use the UriMatcher to see what kind of query we have and format the db query accordingly
        switch (sURIMatcher.match(uri)) {
            case SEARCH_SUGGEST:
                if (selectionArgs == null) {
                  throw new IllegalArgumentException(
                      "selectionArgs must be provided for the Uri: " + uri);
                }
                return getSuggestions(selectionArgs[0]);
            case SEARCH_WORDS:
                if (selectionArgs == null) {
                  throw new IllegalArgumentException(
                      "selectionArgs must be provided for the Uri: " + uri);
                }
                return search(selectionArgs[0]);
            case GET_WORD:
                return getWord(uri);
            case REFRESH_SHORTCUT:
                return refreshShortcut(uri);
            default:
                throw new IllegalArgumentException("Unknown Uri: " + uri);
        }
    }

    private Cursor getSuggestions(String query) {
      query = query.toLowerCase();
      String[] columns = new String[] {
          BaseColumns._ID,
          DictionaryDatabase.KEY_WORD,
          DictionaryDatabase.KEY_DEFINITION,
       /* SearchManager.SUGGEST_COLUMN_SHORTCUT_ID,
                        (only if you want to refresh shortcuts) */
          SearchManager.SUGGEST_COLUMN_INTENT_DATA_ID};

      return mDictionary.getWordMatches(query, columns);
    }

    private Cursor search(String query) {
      query = query.toLowerCase();
      String[] columns = new String[] {
          BaseColumns._ID,
          DictionaryDatabase.KEY_WORD,
          DictionaryDatabase.KEY_DEFINITION};

      return mDictionary.getWordMatches(query, columns);
    }

    private Cursor getWord(Uri uri) {
      String rowId = uri.getLastPathSegment();
      String[] columns = new String[] {
          DictionaryDatabase.KEY_WORD,
          DictionaryDatabase.KEY_DEFINITION};

      return mDictionary.getWord(rowId, columns);
    }

    private Cursor refreshShortcut(Uri uri) {
      /* This won't be called with the current implementation, but if we include
       * {@link SearchManager#SUGGEST_COLUMN_SHORTCUT_ID} as a column in our suggestions table, we
       * could expect to receive refresh queries when a shortcutted suggestion is displayed in
       * Quick Search Box. In which case, this method will query the table for the specific
       * word, using the given item Uri and provide all the columns originally provided with the
       * suggestion query.
       */
      String rowId = uri.getLastPathSegment();
      String[] columns = new String[] {
          BaseColumns._ID,
          DictionaryDatabase.KEY_WORD,
          DictionaryDatabase.KEY_DEFINITION,
          SearchManager.SUGGEST_COLUMN_SHORTCUT_ID,
          SearchManager.SUGGEST_COLUMN_INTENT_DATA_ID};

      return mDictionary.getWord(rowId, columns);
    }

    /**
     * This method is required in order to query the supported types.
     * It's also useful in our own query() method to determine the type of Uri received.
     */
    @Override
    public String getType(Uri uri) {
        switch (sURIMatcher.match(uri)) {
            case SEARCH_WORDS:
                return WORDS_MIME_TYPE;
            case GET_WORD:
                return DEFINITION_MIME_TYPE;
            case SEARCH_SUGGEST:
                return SearchManager.SUGGEST_MIME_TYPE;
            case REFRESH_SHORTCUT:
                return SearchManager.SHORTCUT_MIME_TYPE;
            default:
                throw new IllegalArgumentException("Unknown URL " + uri);
        }
    }

    // Other required implementations...

    @Override
    public Uri insert(Uri uri, ContentValues values) {
        throw new UnsupportedOperationException();
    }

    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs) {
        throw new UnsupportedOperationException();
    }

    @Override
    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
        throw new UnsupportedOperationException();
    }

}