Android 4.2中sqlite操作问题：openDatabase()时需要显示指定路径

写了个小app,需要将数据存入sqlite中，按照文档说明，如下方式创建数据库文件：

            db_aimu = SQLiteDatabase.openOrCreateDatabase("test.db", null);

运行时logcat报错：

02-22 09:16:28.214: E/SQLiteLog(26781): (14) cannot open file at line 30176 of [00bb9c9ce4]
02-22 09:16:28.222: E/SQLiteLog(26781): (14) os_unix.c:30176: (2) open(//test.db) - 
02-22 09:16:28.331: E/SQLiteDatabase(26781): Failed to open database 'test.db'.
02-22 09:16:28.331: E/SQLiteDatabase(26781): android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14): Could not open database
02-22 09:16:28.331: E/SQLiteDatabase(26781):     at android.database.sqlite.SQLiteConnection.nativeOpen(Native Method)
02-22 09:16:28.331: E/SQLiteDatabase(26781):     at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:209)
02-22 09:16:28.331: E/SQLiteDatabase(26781):     at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:193)
02-22 09:16:28.331: E/SQLiteDatabase(26781):     at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:463)
02-22 09:16:28.331: E/SQLiteDatabase(26781):     at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:185)
02-22 09:16:28.331: E/SQLiteDatabase(26781):     at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:177)
02-22 09:16:28.331: E/SQLiteDatabase(26781):     at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:804)
02-22 09:16:28.331: E/SQLiteDatabase(26781):     at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:789)
02-22 09:16:28.331: E/SQLiteDatabase(26781):     at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:694)
02-22 09:16:28.331: E/SQLiteDatabase(26781):     at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:709)
02-22 09:16:28.331: E/SQLiteDatabase(26781):     at com.test.test.<init>(test.java:21)
02-22 09:16:28.331: E/SQLiteDatabase(26781):     at com.test.test.getInstance(test.java:34)
02-22 09:16:28.331: E/SQLiteDatabase(26781):     at com.test.MainActivity$2.run(MainActivity.java:71)

似乎是打开数据文件失败。

网上查阅资料，查看官方文档，都没有找到原因。最后有人提到：

I faced this problem, it was because in 4.2, there is multi users support, and if you are testing with non-admin user, you cannot acess /data/data path..

In my case i’m using the path:

context.getFilesDir().getAbsolutePath().replace("files", "databases") + File.separator

http://androiddev.orkitra.com/?p=13793

就是说，androi4.2中引入了多用户机制，普通用户无法访问根目录下的/data/data目录，因而无法创建数据库文件。而我的安卓模拟器确实是最新的4.2版本，因此就会有这种问题。

知道原因就很好解决了，按照上面的方法使用context.getFilesDir().getAbsolutePath()获取绝对路径即可。