Android基础-ContentProvider

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 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 ContentProvider如何存储数据 每一个ContentProvider都有一个Uri来标识它本身android provider Contacts Phones CONTENT URIContentProvider存储数据的形式 ContentProvider的查找 finalCursorContentResolver query Uriuri String projection Stringselection String selectionArgs StringsortOrder 使用者自行管理Cursor的生命周期finalCursorActivity managedQuery Uriuri String projection Stringselection String selectionArgs StringsortOrder 由所在的Activity来管理Cursor的生命周期 ContentProvider的查找 String projection newString People ID People COUNT People NAME People NUMBER Uricontacts People CONTENT URI CursormanagedCursor managedQuery contacts projection Whichcolumnstoreturnnull Whichrowstoreturn allrows null Selectionarguments none PuttheresultsinascendingorderbynamePeople NAME ASC ContentProvider的查找 privatevoidgetColumnData Cursorcur if cur moveToFirst Stringname phoneNumber intnameColumn cur getColumnIndex People NAME intphoneColumn cur getColumnIndex People NUMBER StringimagePath do name cur getString nameColumn phoneNumber cur getString phoneColumn while cur moveToNext 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 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 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 更新和删除 更新 ContentResolver update 删除 ContentResolver delete 如何创建ContentProvider 通过Sqlite的方式建立ContentProvider继承ContentProvider类实现SQLi