Android-Studio-SQLite不调用oncreate方法教学

1、创立类继承 SQLiteOpenHelper public class MyHelper extends SQLiteOpenHelper public MyHelper(Context context) super(context/abc.db,/null,l)；Overridepublic void onCreate(SQLiteDatabase db) 学生表数据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) )调试时发现，onCreate方法不会调用，一般是由于设备或者模拟器中已经存在abc.db文件, 程序会直接翻开，不会新建，所以不会调用onCreate方法。如果需要调用可以手动删除该文件，或者修改数据库文件名称后重新运行。通过 DDMS (Dalvik Debug Monitor Service)来查看启动路径：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

5、adle/“J f-JLile Edit13 5d A o Enos 驻1sajmds InoABl&ProjectFavoritesDebug Logcat StructureVersion ControlnProfilerBuildBuild VariantsLayout Captures Device File ExplorerAlt+1 ountBook Alt+2人代+5 ExpenseProcesActivity.javaAlt+6Alt+7Alt+9ateQ Nexus 5X API 29 Q OneFragA Resource ManagerB TerminalAlt+F12I

6、per name, CursorFactory factory,H, 一般可以执行建库，建表的操作2、查看data文件夹文件目录：/data/data/包名/databases/数据库名在该步骤，.db文件是无法直接翻开的，选中文件，右击，可以save as到其它目录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、通过Navicat Premium或者SQLite Expert Professional来查看.db文件中的数据我用的

9、工具是Navicat Premium,当然还有其它的工具可以选用Navicat Premium:先创立连接（数据库文件选择步骤2中保存的文件）qianbao -编辑连接高级附加的数据库HTTP数据库文件:用户名：区保存空码查看数据库Navicat Premium之件 编辑 查看 收藏夹 工具 窗口 帮助 f触发器邮查询国报表备份SQLite Expert Professional:翻开该软件后，直接将.db文件拖入到左侧数据库栏中: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