我正在使用 Cursor 从数据库中获取数据(这是关于 map 上的叠加标记的信息)。我正在借助这些数据加载 map 。通过 Cursor 与数据库的交互是在 asyncTask 中完成的。
现在这是我面临的问题。如果我在光标运行加载 map 时按下后退按钮(即在 while 循环中加载覆盖标记的中间)，我会收到此错误:
Caused by: java.lang.IllegalStateException: attempt to re-open an already-closed object: android.database.sqlite.SQLiteQuery (mSql = SELECT _id, category, latitude, longitude FROM node)
这是它的完整踪迹:
12-21 11:11:30.173: E/AndroidRuntime(2824): FATAL EXCEPTION: AsyncTask #5
12-21 11:11:30.173: E/AndroidRuntime(2824): java.lang.RuntimeException: An error occured while executing doInBackground()
12-21 11:11:30.173: E/AndroidRuntime(2824): at android.os.AsyncTask$3.done(AsyncTask.java:200)
12-21 11:11:30.173: E/AndroidRuntime(2824): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
12-21 11:11:30.173: E/AndroidRuntime(2824): at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
12-21 11:11:30.173: E/AndroidRuntime(2824): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
12-21 11:11:30.173: E/AndroidRuntime(2824): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
12-21 11:11:30.173: E/AndroidRuntime(2824): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
12-21 11:11:30.173: E/AndroidRuntime(2824): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
12-21 11:11:30.173: E/AndroidRuntime(2824): at java.lang.Thread.run(Thread.java:1102)
12-21 11:11:30.173: E/AndroidRuntime(2824): Caused by: java.lang.IllegalStateException: attempt to re-open an already-closed object: android.database.sqlite.SQLiteQuery (mSql = SELECT _id, category, latitude, longitude FROM node)
12-21 11:11:30.173: E/AndroidRuntime(2824): at android.database.sqlite.SQLiteClosable.acquireReference(SQLiteClosable.java:34)
12-21 11:11:30.173: E/AndroidRuntime(2824): at android.database.sqlite.SQLiteQuery.fillWindow(SQLiteQuery.java:64)
12-21 11:11:30.173: E/AndroidRuntime(2824): at android.database.sqlite.SQLiteCursor.fillWindow(SQLiteCursor.java:299)
12-21 11:11:30.173: E/AndroidRuntime(2824): at android.database.sqlite.SQLiteCursor.onMove(SQLiteCursor.java:271)
12-21 11:11:30.173: E/AndroidRuntime(2824): at android.database.AbstractCursor.moveToPosition(AbstractCursor.java:188)
12-21 11:11:30.173: E/AndroidRuntime(2824): at android.database.AbstractCursor.moveToNext(AbstractCursor.java:256)
12-21 11:11:30.173: E/AndroidRuntime(2824): at org.mid.kew.activities.MapPageActivity$MapLoadingAsyncTask.doInBackground(MapPageActivity.java:632)
12-21 11:11:30.173: E/AndroidRuntime(2824): at org.mid.kew.activities.MapPageActivity$MapLoadingAsyncTask.doInBackground(MapPageActivity.java:1)
12-21 11:11:30.173: E/AndroidRuntime(2824): at android.os.AsyncTask$2.call(AsyncTask.java:185)
12-21 11:11:30.173: E/AndroidRuntime(2824): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
12-21 11:11:30.173: E/AndroidRuntime(2824): ... 4 more
这是我在 asyncTask 中使用的代码的快照
在DoInBackground方法下
openKewDataBase();
Cursor cursor = getCursorForOverLayIcons();
startManagingCursor(cursor);
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
...
cursor.moveToNext();
}
cursor.close();
在onPostExecute方法下
....
closeKewDataBase();
据我所知，它的崩溃发生在“cursor.moveToNext();”
最佳答案
当您使用 cursor.close() 手动关闭游标时，您不应调用 startManagingCursor(cursor)。您需要选择其中之一。
当您在 AsyncTask 中执行此操作时，您几乎肯定不希望封闭的 Activity 为您管理光标，因为 AsyncTask 可以比 Activity 长寿。所以只需手动执行即可。
(我假设 AsyncTask 是您的 Activity 的内部类。)
关于android - 获取 java.lang.IllegalStateException : attempt to re-open an already-closed object: when using cursor in Android，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/8589346/