Android基础-ContentProviderppt课件

.,1,Android四大组件之ContentProvider,.,2,一、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,.,3,如何访问ContentProvider,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：update删除：delete,.,4,ContentProvider如何存储数据,每一个ContentProvider都有一个Uri来标识它本身vider.Contacts.Phones.CONTENT_URIContentProvider存储数据的形式：,.,5,ContentProvider的查找,finalCursorContentResolver.query(Uriuri,Stringprojection,Stringselection,StringselectionArgs,StringsortOrder)使用者自行管理Cursor的生命周期finalCursorActivity.managedQuery(Uriuri,Stringprojection,Stringselection,StringselectionArgs,StringsortOrder)由所在的Activity来管理Cursor的生命周期,.,6,ContentProvider的查找,Stringprojection=newStringPeople._ID,People._COUNT,People.NAME,People.NUMBER;Uricontacts=People.CONTENT_URI;CursormanagedCursor=managedQuery(contacts,projection,/Whichcolumnstoreturnnull,/Whichrowstoreturn(allrows)null,/Selectionarguments(none)/PuttheresultsinascendingorderbynamePeople.NAME+ASC);,.,7,ContentProvider的查找,privatevoidgetColumnData(Cursorcur)if(cur.moveToFirst()Stringname,phoneNumber;intnameColumn=cur.getColumnIndex(People.NAME);intphoneColumn=cur.getColumnIndex(People.NUMBER);StringimagePath;doname=cur.getString(nameColumn);phoneNumber=cur.getString(phoneColumn);while(cur.moveToNext();,.,8,修改ContentProvider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,.,9,增加一条新记录,ContentValuesvalues=newContentValues();/AddAbrahamLincolntocontactsandmakehimafavorite.values.put(People.NAME,AbrahamLincoln);/1=thenewcontactisaddedtofavorites/0=thenewcontactisnotaddedtofavoritesvalues.put(People.STARRED,1);Uriuri=getContentResolver().insert(People.CONTENT_URI,values);,.,10,已有记录增加新信息,UriphoneUri=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);,.,11,更新和删除,更新：ContentResolver.update()删除：ContentResolver.delete(),.,12,如何创建ContentProvider？,通过Sqlite的方式建立ContentProvider继承ContentProvider类实现SQLiteOpenHe