Android-Studio-SQLite不調(diào)用oncreate方法教學(xué)

1、創(chuàng)立類繼承 SQLiteOpenHelper public class MyHelper extends SQLiteOpenHelper public MyHelper(Context context) super(context/abc.db,/null,l)；Overridepublic void onCreate(SQLiteDatabase db) 學(xué)生表數(shù)據(jù)db.execSQL(create table student(id integer primary key autoincrement,name varchar(20),sex varchar(lO),birth intege

2、r,department varchar(20),address varchar(20);Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) )調(diào)試時(shí)發(fā)現(xiàn)，onCreate方法不會(huì)調(diào)用，一般是由于設(shè)備或者模擬器中已經(jīng)存在abc.db文件, 程序會(huì)直接翻開(kāi)，不會(huì)新建，所以不會(huì)調(diào)用onCreate方法。如果需要調(diào)用可以手動(dòng)刪除該文件，或者修改數(shù)據(jù)庫(kù)文件名稱后重新運(yùn)行。通過(guò) DDMS (Dalvik Debug Monitor Service)來(lái)查看啟動(dòng)路徑：View - Tool Wind

3、ows - Device File Explorer!) accountBook C:AnneAnneProjectaccountBook - .appsrcmainjavacomhyldaoDBOpenHelper.java app - Android StudView Navigate Code Analyze Refactor Build Run Tools VCS Window Help mailTool WindowsQ MaQuick DefinitionCtrl+Shift+|Show SiblingsQuick DocumentationCtrl+QParameter Info

4、Ctrl + PQType InfoCtrl+Shift+POContext InfoAlt+Q-Recent FilesCtrl + ERecently Changed FilesRecent LocationsCtrl+Shift+ERecent ChangesAlt+Shift+CCompare With.Ctrl + DCompare with ClipboardQuick Switch Scheme.Ctrl+j. yToolbarVTool Window BarsMStatus BarVNavigation Bar/ 4Active EditorTODO Event Log ,Gr

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6、per name, CursorFactory factory,H, 一般可以執(zhí)行建庫(kù)，建表的操作2、查看data文件夾文件目錄：/data/data/包名/databases/數(shù)據(jù)庫(kù)名在該步驟，.db文件是無(wú)法直接翻開(kāi)的，選中文件，右擊，可以save as到其它目錄Device File Exploreru -UH Emulator Nexus_5X_API_29 Android 10, API 29NamePermissionsDateSizef M arwxnu/u-uv-4 KDdrwx2020-09-19 09:364 KB drwx2020-09-19 09:364 KB com.

7、hyLaccountbookdrwx2020-07-07 09:484 KB cachedrwxrwsx2020-07-07 09:394 KB codecachedrwxrws-x2021-07-08 07:314 KB databasesdrwxrwxx2020-07-07 09:484 KBjfqianbao.db-rw-rw2021-07-08 07:4428 KB% qianbao.db-journal-rw rw_2021-07-08 07:440B sharedprefsdrwxrwxx2020-07-07 09:494 KB com.hyl.anne 叩 pdrwx2020-0

8、9-19 09:364 KB com.hyLmwmdemodrwx2020-08-20 02:554 KB M com.mshservicedrwx2021-02-02 09:324 KB M drwx2020-07-07 09:384 KB drwx2020-08-14 08:584 KB drmdrwxrwx2020-07-07 09:374 KBgsidrwx2020-07-07 09:374 KB localdrwxr-xx2020-07-07 09:374 KB3、通過(guò)Navicat Premium或者SQLite Expert Professional來(lái)查看.db文件中的數(shù)據(jù)我用的

9、工具是Navicat Premium,當(dāng)然還有其它的工具可以選用Navicat Premium:先創(chuàng)立連接（數(shù)據(jù)庫(kù)文件選擇步驟2中保存的文件）qianbao -編輯連接高級(jí)附加的數(shù)據(jù)庫(kù)HTTP數(shù)據(jù)庫(kù)文件:用戶名：區(qū)保存空碼查看數(shù)據(jù)庫(kù)Navicat Premium之件 編輯 查看 收藏夾 工具 窗口 幫助 f觸發(fā)器郵查詢國(guó)報(bào)表備份SQLite Expert Professional:翻開(kāi)該軟件后，直接將.db文件拖入到左側(cè)數(shù)據(jù)庫(kù)欄中:SQl ite Fxpcrt Professional 53 (xM)File View Database Import/Expoft Object SQL Transa(tion Scripting Tools HelpMaulUqukiSkyDatabase: nvms222 Table: student Fite: C:UsefSKzqDesktopmrms222.dbSQlite library sqlite3.dll 3.27.2 FTS3 FTS4 FTS5 RTREE ICU1mrms222studentrowid idname age emailDatabase Extensions Schema Data