java.lang.IllegalStateException 错误原因及解决方法小记

java.lang.IllegalStateException: Cannot perform this operation because the connection pool has been closed.

at android.database.sqlite.SQLiteConnectionPool.throwIfClosedLocked(SQLiteConnectionPool.java:962)

at android.database.sqlite.SQLiteConnectionPool.waitForConnection(SQLiteConnectionPool.java:599)

at android.database.sqlite.SQLiteConnectionPool.acquireConnection(SQLiteConnectionPool.java:348)

at android.database.sqlite.SQLiteSession.acquireConnection(SQLiteSession.java:894)

at android.database.sqlite.SQLiteSession.executeForCursorWindow(SQLiteSession.java:834)

at android.database.sqlite.SQLiteQuery.fillWindow(SQLiteQuery.java:62)

at android.database.sqlite.SQLiteCursor.fillWindow(SQLiteCursor.java:144)

at android.database.sqlite.SQLiteCursor.getCount(SQLiteCursor.java:133)

在项目中遇到如上描述问题，连续调用连个线程操作数据库时引起的。

出现多个sqlliteopenhelper 及产生多个connection对象，这个应当被禁止的，可以使用单例模式，使得全局仅有一个入口可操作数据库。