精通Android4实例

package com.ai.android.book.provider; import java.util.HashMap; 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; import com.ai.android.book.provider.BookProviderMetaData.BookTableMetaData; public class BookProvider extends ContentProvider { //Logging helper tag. No significance to providers. private static final String TAG = "BookProvider"; //Projection maps are similar to "as" construct //in an sql statement where by you can rename the //columns. private static HashMap<String, String> sBooksProjectionMap; static { sBooksProjectionMap = new HashMap<String, String>(); sBooksProjectionMap.put(BookTableMetaData._ID, BookTableMetaData._ID); //name, isbn, author sBooksProjectionMap.put(BookTableMetaData.BOOK_NAME, BookTableMetaData.BOOK_NAME); sBooksProjectionMap.put(BookTableMetaData.BOOK_ISBN, BookTableMetaData.BOOK_ISBN); sBooksProjectionMap.put(BookTableMetaData.BOOK_AUTHOR, BookTableMetaData.BOOK_AUTHOR); //created date, modified date sBooksProjectionMap.put(BookTableMetaData.CREATED_DATE, BookTableMetaData.CREATED_DATE); sBooksProjectionMap.put(BookTableMetaData.MODIFIED_DATE, BookTableMetaData.MODIFIED_DATE); } //Provide a mechanism to identify //all the incoming uri patterns. private static final UriMatcher sUriMatcher; private static final int INCOMING_BOOK_COLLECTION_URI_INDICATOR = 1; private static final int INCOMING_SINGLE_BOOK_URI_INDICATOR = 2; static { sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH); sUriMatcher.addURI(BookProviderMetaData.AUTHORITY, "books", INCOMING_BOOK_COLLECTION_URI_INDICATOR); sUriMatcher.addURI(BookProviderMetaData.AUTHORITY, "books/#", INCOMING_SINGLE_BOOK_URI_INDICATOR); } /** * This class helps open, create, and upgrade the database file. */ private static class DatabaseHelper extends SQLiteOpenHelper { DatabaseHelper(Context context) { super(context, BookProviderMetaData.DATABASE_NAME, null, BookProviderMetaData.DATABASE_VERSION); } @Override public void onCreate(SQLiteDatabase db) { Log.d(TAG,"inner oncreate called"); db.execSQL("CREATE TABLE " + BookTableMetaData.TABLE_NAME + " (" + BookTableMetaData._ID + " INTEGER PRIMARY KEY," + BookTableMetaData.BOOK_NAME + " TEXT," + BookTableMetaData.BOOK_ISBN + " TEXT," + BookTableMetaData.BOOK_AUTHOR + " TEXT," + BookTableMetaData.CREATED_DATE + " INTEGER," + BookTableMetaData.MODIFIED_DATE + " INTEGER" + ");"); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { Log.d(TAG,"inner onupgrade called"); Log.w(TAG, "Upgrading database from version " + oldVersion + " to " + newVersion + ", which will destroy all old data"); db.execSQL("DROP TABLE IF EXISTS " + BookTableMetaData.TABLE_NAME); onCreate(db); } } private DatabaseHelper mOpenHelper; @Override public boolean onCreate() { Log.d(TAG,"main onCreate called"); mOpenHelper = new DatabaseHelper(getContext()); return true; } @Override public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) { SQLiteQueryBuilder qb = new SQLiteQueryBuilder(); switch (sUriMatcher.match(uri)) { case INCOMING_BOOK_COLLECTION_URI_INDICATOR: qb.setTables(BookTableMetaData.TABLE_NAME); qb.setProjectionMap(sBooksProjectionMap); break; case INCOMING_SINGLE_BOOK_URI_INDICATOR: qb.setTables(BookTableMetaData.TABLE_NAME); qb.setProjectionMap(sBooksProjectionMap); qb.appendWhere(BookTableMetaData._ID + "=" + uri.getPathSegments().get(1)); break; default: throw new IllegalArgumentException("Unknown URI " + uri); } // If no sort order is specified use the default String orderBy; if (TextUtils.isEmpty(sortOrder)) { orderBy = BookTableMetaData.DEFAULT_SORT_ORDER; } else { orderBy = sortOrder; } // Get the database and run the query SQLiteDatabase db = mOpenHelper.getReadableDatabase(); Cursor c = qb.query(db, projection, selection, selectionArgs, null, null, orderBy); //example of getting a count int i = c.getCount(); // Tell the cursor what uri to watch, // so it knows when its source data changes c.setNotificationUri(getContext().getContentResolver(), uri); return c; } @Override public String getType(Uri uri) { switch (sUriMatcher.match(uri)) { case INCOMING_BOOK_COLLECTION_URI_INDICATOR: return BookTableMetaData.CONTENT_TYPE; case INCOMING_SINGLE_BOOK_URI_INDICATOR: return BookTableMetaData.CONTENT_ITEM_TYPE; default: throw new IllegalArgumentException("Unknown URI " + uri); } } @Override public Uri insert(Uri uri, ContentValues initialValues) { // Validate the requested uri if (sUriMatcher.match(uri) != INCOMING_BOOK_COLLECTION_URI_INDICATOR) { throw new IllegalArgumentException("Unknown URI " + uri); } ContentValues values; if (initialValues != null) { values = new ContentValues(initialValues); } else { values = new ContentValues(); } Long now = Long.valueOf(System.currentTimeMillis()); // Make sure that the fields are all set if (values.containsKey(BookTableMetaData.CREATED_DATE) == false) { values.put(BookTableMetaData.CREATED_DATE, now); } if (values.containsKey(BookTableMetaData.MODIFIED_DATE) == false) { values.put(BookTableMetaData.MODIFIED_DATE, now); } if (values.containsKey(BookTableMetaData.BOOK_NAME) == false) { throw new SQLException( "Failed to insert row because Book Name is needed " + uri); } if (values.containsKey(BookTableMetaData.BOOK_ISBN) == false) { values.put(BookTableMetaData.BOOK_ISBN, "Unknown ISBN"); } if (values.containsKey(BookTableMetaData.BOOK_AUTHOR) == false) { values.put(BookTableMetaData.BOOK_ISBN, "Unknown Author"); } SQLiteDatabase db = mOpenHelper.getWritableDatabase(); long rowId = db.insert(BookTableMetaData.TABLE_NAME, BookTableMetaData.BOOK_NAME, values); if (rowId > 0) { Uri insertedBookUri = ContentUris.withAppendedId( BookTableMetaData.CONTENT_URI, rowId);