Android Open Source - android_examples Character Provider

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The source code is released under:

Copyright (c) 2009 Florida State University. All rights reserved. Developed by: FSU Android Group Florida State University http://www.cs.fsu.edu Permission is hereby gra...

Java Source Code

package fsu.android.ProviderExample;
//ww w .jav  a  2  s .  c o m
import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Context;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteQueryBuilder;
import android.net.Uri;
import android.text.TextUtils;
import android.util.Log;


public final class CharacterProvider extends ContentProvider {
  public static final String PROVIDER_NAME = 
    "fsu.android.ProviderExample.CharacterProvider";
  public static final Uri CONTENT_URI = 
    Uri.parse("content://"+ PROVIDER_NAME + "/characters");
  
  //column names
  public static final String _ID = "_id";
  public static final String Name = "name";
  public static final String Agility = "agility";
  public static final String Intelligence = "intelligence";
  public static final String Reflexes = "reflexes";
  public static final String Awareness = "awareness";
  public static final String Stamina = "stamina";
  public static final String Willpower = "willpower";
  public static final String Strength = "strength";
  public static final String Perception = "perception";
  public static final String Void = "vvoid";
  public static final String Playerid = "playerid";
  
  //column numbers
  public static final int cName = 1;
  public static final int cAgility = 2;   
  public static final int cIntelligence = 3;
  public static final int cReflexes = 4;
  public static final int cAwareness = 5;
  public static final int cStamina = 6;
  public static final int cWillpower = 7;
  public static final int cStrength = 8;
  public static final int cPerception = 9;
  public static final int cVoid = 10;
  public static final int cPlayerid = 11;
  
  //URI types
  private static final int CharacterName = 1;
  private static final int CharacterId = 2;
     
  private static final UriMatcher uriMatcher;
  static {
    uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
    uriMatcher.addURI(PROVIDER_NAME, "characters/#", CharacterId);      
    uriMatcher.addURI(PROVIDER_NAME, "characters", CharacterName);
  }   
  
  private SQLiteDatabase characterDB;
  
  // By placing all of the DB information in constants, including the SQL query
  // to create it, changing the internal structure won't break your code.
  // Fascinating!
  private static final String DATABASE_NAME = "CharactersDb";
  private static final String DATABASE_TABLE = "CharactersTable";
  private static final int DATABASE_VERSION = 2;
  private static final String DATABASE_CREATE =
    "create table " + DATABASE_TABLE + 
    " (_id integer primary key autoincrement, " +
    "name string, " +
    "agility integer, " +
    "intelligence integer, " +
    "reflexes integer, " +
    "awareness integer, " +
    "stamina integer, " +
    "willpower integer, " +
    "strength integer, " +
    "perception integer, "  +
    "vvoid integer, " +
    "playerid integer);";
  
  /**
   * The DB helpers provide a quick and safe way to open the SQL database
   * from within Android, create the new database, and upgrade it.
   */
  private static class DatabaseHelper extends SQLiteOpenHelper {
    DatabaseHelper(Context context) {
      super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
      db.execSQL(DATABASE_CREATE);
    }
    
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
      Log.w("CharacterProvider DB", "Upgrading database from version " + 
        oldVersion + " to " + newVersion + ", destroying previous data");
//db.execSQL("DROP TABLE IF EXISTS titles");  //doesn't make sense for this code.
          onCreate(db);
    }
  }


//--Provider Methods--//  //reorder these so that they are in a more logical fashion (create -> insert, remove -> upgrade -> delete)
public CharacterProvider() {
  // TODO Auto-generated constructor stub
}

/**
 * Called when the database is first created. Works best with a helper object
 * to do the heavy lifting, as seen here.
 */
@Override
public boolean onCreate() {
  Context context = getContext();
  DatabaseHelper dbHelper = new DatabaseHelper(context);
    characterDB = dbHelper.getWritableDatabase();
    return (characterDB == null) ? false : true;
}

/**
 * Basic insert method. Also notifies users of the provider about the change.
 * 
 * @return row  the Uri pointing to the inserted row.
 */
@Override
public Uri insert(Uri uri, ContentValues values) {
  long rowID = characterDB.insert(DATABASE_TABLE, "", values);
           
  if (rowID > 0) {
    Uri _uri = ContentUris.withAppendedId(CONTENT_URI, rowID);
    getContext().getContentResolver().notifyChange(_uri, null);    
    return _uri;                
  } else
    throw new SQLException("Failed to insert row into " + uri +
                 " "+ values.toString());
}

/**
 * Basic delete method. Performs a query, and deletes the results from the
 * database. Notifies users of the provider about the change.
 * 
 * @return count  the number of rows removed
 */
@Override
public int delete(Uri arg0, String arg1, String[] arg2) {
  int count = 0;
  
  switch (uriMatcher.match(arg0)) {
  case CharacterName:
    count = characterDB.delete(
          DATABASE_TABLE,
          arg1, 
          arg2);
      break;
  case CharacterId: 
    String id = arg0.getPathSegments().get(1);
        count = characterDB.delete(
              DATABASE_TABLE,                        
              _ID + " = " + id + 
              (!TextUtils.isEmpty(arg1) ? " AND (" + 
              arg1 + ')' : ""), 
              arg2
            );
        break;
  default:
    throw new IllegalArgumentException( "Unknown URI " + arg0);
  }
  
  return count;  //used to be return 0. why?
}

/**
 * Provides the basic and essential method by which the content resolver will
 * query the database. The options are passed in as a managed query, in pieces.
 * For specialized access, raw SQL queries can be called from custom methods.
 * 
 * @return results  cursor to the results of the query (empty if none)
 */
@Override
public Cursor query(Uri uri, String[] projection, String selection,
          String[] selectionArgs, String sortOrder) {
  
  SQLiteQueryBuilder sqlBuilder = new SQLiteQueryBuilder();
  sqlBuilder.setTables(DATABASE_TABLE);
  
  if (uriMatcher.match(uri) == CharacterId)
    sqlBuilder.appendWhere(_ID + " = " + uri.getPathSegments().get(1));              
  
  Cursor c = sqlBuilder.query(
    characterDB, 
      projection, 
      selection, 
      selectionArgs, 
      null, 
      null, 
      sortOrder);
     
  //register to watch a content URI for changes
  c.setNotificationUri(getContext().getContentResolver(), uri);
  
  return c;
}

/**
 * The basic types are single and multiple, represented as .item and .dir Uri's.    //MORE!
 */
@Override
public String getType(Uri uri) {
  switch (uriMatcher.match(uri)) {
  case CharacterName:
    return "vnd.android.cursor.dir/vnd.CharacterProvider";
    case CharacterId:   
        return "vnd.android.cursor.dir/vnd.CharacterProvider";
    default:
        throw new IllegalArgumentException("Unsupported URI: " + uri);        
    }   
}

/**
 * The update method provides necessary housekeeping in the event that the
 * internal database structure is changed in a later release. At the most basic
 * level, the old database or table is deleted and onCreate (the new one) is
 * called to replace it. Of course, it is also possible to migrate the existing
 * data from the old table to the new table as required.
 */
@Override
public int update(Uri uri, ContentValues values, String selection, 
          String[] selectionArgs) {
  int count = 0;
    
  switch (uriMatcher.match(uri)) {
  case CharacterName:
    count = characterDB.update(
          DATABASE_TABLE, 
          values,
          selection, 
          selectionArgs);
    break;
  case CharacterId: 
    count = characterDB.update(
          DATABASE_TABLE, 
          values,
          _ID + " = " + uri.getPathSegments().get(1) + 
          (!TextUtils.isEmpty(selection) ? " AND (" + 
          selection + ')' : ""), 
          selectionArgs);
    break;
  default:
    throw new IllegalArgumentException("Unknown URI " + uri);    
  }    
  
  //notify listeners about the change
  getContext().getContentResolver().notifyChange(uri, null);
  return count;
}

} //end of CharacterProvider class

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