Android基础ContentProvider.ppt

1、Android四大组件之ContentProvider,一、什么是ContentProvider,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Provider audio、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,如何访问ContentProvider,借助工具类ContentResolver 获得ContentResolver 由activity或cont

2、ext的方法：getContentResolver() 使用ContentResolver的方法访问数据库 查找：query 插入：insert 更新：update 删除：delete,Content Provider如何存储数据,每一个Content Provider都有一个Uri来标识它本身 vider.Contacts.Phones.CONTENT_URI Content Provider存储数据的形式：,Content Provider的查找,final Cursor ContentResolver.query(Uri uri, String projection

3、, 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, String projection, String selection, String selectionArgs, String sortOrder) 由所在的Activity来管理Cursor的生命周期,Content Provider的查找,String projection = new String People._ID, People._CO

4、UNT, People.NAME, People.NUMBER ; Uri contacts = People.CONTENT_URI; Cursor managedCursor = managedQuery(contacts, projection, / Which columns to return null, / Which rows to return (all rows) null, / Selection arguments (none) / Put the results in ascending order by name People.NAME + ASC);,Content

5、 Provider的查找,private void getColumnData(Cursor cur) if (cur.moveToFirst() String name, phoneNumber; int nameColumn = cur.getColumnIndex(People.NAME); int phoneColumn = cur.getColumnIndex(People.NUMBER); String imagePath; do name = cur.getString(nameColumn); phoneNumber = cur.getString(phoneColumn);

6、while (cur.moveToNext(); ,修改Content Provider的数据,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、ContentResolver,增加一条新记录,ContentValues values = new ContentValues(); / Add Abraham Lincoln to contacts and make him a favorite. values.put(People.NAME, Abraham Lincoln); / 1 =

7、 the new contact is added to favorites / 0 = the new contact is not added to favorites values.put(People.STARRED, 1); Uri uri = getContentResolver().insert(People.CONTENT_URI, values);,已有记录增加新信息,Uri phoneUri = null; phoneUri = 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);,更新和删除,更新： ContentResolver.update() 删除： ContentResolver.delete(),如何创建Content Provider？,通过Sqlite的方式建立ContentProvider 继承ContentProvider类 实现SQLit