Android基础-ContentProvider

1、ContentProvider用来存储和检索数据ContentProvider是应用之间互相访问数据的唯一方法Android自身提供了一些常用的Provideraudio、video、image、contacts等如果你想使你的数据能够共享，要么建立一个你自己的ContentProvider；要么往已存在的ContentProvider中写数据借助工具类ContentResolver 获得ContentResolver由activity或context的方法：getContentResolver() 使用ContentResolver的方法访问数据库查找：query插入：insert更新：up

2、date删除：delete每一个Content Provider都有一个Uri来标识它本身vider.Contacts.Phones.CONTENT_URIContent Provider存储数据的形式：final Cursor ContentResolver.query(Uri uri, String projection, String selection, String selectionArgs, String sortOrder)使用者自行管理Cursor的生命周期final Cursor Activity.managedQuery(Uri uri, Strin

3、g projection, String selection, String selectionArgs, String sortOrder)由所在的Activity来管理Cursor的生命周期String projection = new String People._ID, People._COUNT, People.NAME, People.NUMBER ;Uri contacts = People.CONTENT_URI;Cursor managedCursor = managedQuery(contacts, projection, / Which columns to return

4、 null, / Which rows to return (all rows) null, / Selection arguments (none) / Put the results in ascending order by name People.NAME + ASC);private void getColumnData(Cursor cur) if (cur.moveToFirst() String name, phoneNumber; int nameColumn = cur.getColumnIndex(People.NAME); int phoneColumn = cur.g

5、etColumnIndex(People.NUMBER); String imagePath; do name = cur.getString(nameColumn); phoneNumber = cur.getString(phoneColumn); while (cur.moveToNext(); 增加一条新记录：insert给一条已存在的记录增加新信息：insert更新记录：update删除记录：delete借助：ContentValues、ContentResolverContentValues values = new ContentValues();/ Add Abraham Li

6、ncoln to contacts and make him a favorite.values.put(People.NAME, Abraham Lincoln);/ 1 = the new contact is added to favorites/ 0 = the new contact is not added to favoritesvalues.put(People.STARRED, 1);Uri uri = getContentResolver().insert(People.CONTENT_URI, values);Uri phoneUri = null;phoneUri =

7、Uri.withAppendedPath(uri, People.Phones.CONTENT_DIRECTORY);values.clear();values.put(People.Phones.TYPE, People.Phones.TYPE_MOBILE);values.put(People.Phones.NUMBER, 1233214567);getContentResolver().insert(phoneUri, values);更新：ContentResolver.update()删除：ContentResolver.delete()通过Sqlite的方式建立ContentProvider