sqlite如何在IOS开发中应用是本文要介绍的内容，主要是来学习在IOS开发中sqlite数据库的使用方法。sqlite数据库初始化，复制到用户目录，并判断是否数据库已经存在，或者复制是否成功！

在AppDelegate.m中输入以下代码，以便复制预置数据库到指定doucment目录

1. -(BOOL)initializeDb{
2. NSLog(@”initializeDB”);
3. //looktoseeifDBisinknownlocation(~/Documents/$DATABASE_FILE_NAME)
4. //START:code.DatabaseShoppingList.findDocumentsDirectory
5. NSArray*searchPaths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
6. NSString*documentFolderPath=[searchPathsobjectAtIndex:0];
7. //查看文件目录
8. NSLog(@”%@”,documentFolderPath);
9. dbFilePath=[documentFolderPathstringByAppendingPathComponent:@"shopping.db"];
10. //END:code.DatabaseShoppingList.findDocumentsDirectory
11. [dbFilePathretain];
12. //START:code.DatabaseShoppingList.copyDatabaseFileToDocuments
13. if(![[NSFileManagerdefaultManager]fileExistsAtPath:dbFilePath]){
14. //didn’tfinddb,needtocopy
15. NSString*backupDbPath=[[NSBundlemainBundle]pathForResource:@”shopping”ofType:@”db”];
16. if(backupDbPath==nil){
17. //couldn’tfindbackupdbtocopy,bail
18. returnNO;
19. }else{
20. BOOLcopiedBackupDb=[[NSFileManagerdefaultManager]copyItemAtPath:backupDbPathtoPath:dbFilePatherror:nil];
21. if(!copiedBackupDb){
22. //copyingbackupdbFailed,bail
23. returnNO;
24. }
25. }
26. }
27. returnYES;
28. //END:code.DatabaseShoppingList.copyDatabaseFileToDocuments
29. NSLog(@”bottomofinitializeDb”);
30. }
31. -(void)applicationDidFinishLaunching:(UIApplication*)application{
32. //copythedatabasefromthebundleifnecessary
33. if(![selfinitializeDb]){
34. //TODO:alerttheuser!
35. NSLog(@”couldn’tinitdb”);
36. return;
37. }
38. //Addthetabbarcontroller’scurrentviewasasubviewofthewindow
39. [windowaddSubview:tabBarController.view];
40. }