我对android编程完全陌生。我可以看到这个问题之前已经提出过很多次了。但是,我仍然无法看到问题所在。我正在尝试将 SQLite 数据库中的数据连接到列表视图。在 ListActivity 我的 onCreate 如下所示:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_init_key);
getActionBar().setDisplayHomeAsUpEnabled(true);
DBHandler db = new DBHandler(this);
Cursor cursor = db.getKeyPointCursor(1, "Crataegus");
// the desired columns to be bound
String[] columns = new String[] { "question1","answer1" };
// the XML defined views which the data will be bound to
int[] to = new int[] { R.id.question, R.id.answer };
SimpleCursorAdapter mAdapter = new SimpleCursorAdapter(this, R.layout.key_list_entry, cursor, columns, to, 0);
cursor.close();
this.setListAdapter(mAdapter);
}
它引发了以下异常,我希望有人可以帮助我。
09-10 21:52:01.505: W/dalvikvm(10976): threadid=1: thread exiting with uncaught exception (group=0x40c8e1f8)
09-10 21:52:01.510: E/AndroidRuntime(10976): FATAL EXCEPTION: main
09-10 21:52:01.510: E/AndroidRuntime(10976): java.lang.RuntimeException: Unable to start activity ComponentInfo{jem.danskflora/jem.danskflora.InitKeyActivity}: java.lang.IllegalStateException: attempt to re-open an already-closed object: android.database.sqlite.SQLiteQuery (mSql = SELECT * FROM Crataegus WHERE _id=?)
09-10 21:52:01.510: E/AndroidRuntime(10976): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1970)
09-10 21:52:01.510: E/AndroidRuntime(10976): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1995)
09-10 21:52:01.510: E/AndroidRuntime(10976): at android.app.ActivityThread.access$600(ActivityThread.java:128)
09-10 21:52:01.510: E/AndroidRuntime(10976): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1161)
09-10 21:52:01.510: E/AndroidRuntime(10976): at android.os.Handler.dispatchMessage(Handler.java:99)
09-10 21:52:01.510: E/AndroidRuntime(10976): at android.os.Looper.loop(Looper.java:137)
09-10 21:52:01.510: E/AndroidRuntime(10976): at android.app.ActivityThread.main(ActivityThread.java:4514)
09-10 21:52:01.510: E/AndroidRuntime(10976): at java.lang.reflect.Method.invokeNative(Native Method)
09-10 21:52:01.510: E/AndroidRuntime(10976): at java.lang.reflect.Method.invoke(Method.java:511)
09-10 21:52:01.510: E/AndroidRuntime(10976): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:993)
09-10 21:52:01.510: E/AndroidRuntime(10976): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:760)
09-10 21:52:01.510: E/AndroidRuntime(10976): at dalvik.system.NativeStart.main(Native Method)
09-10 21:52:01.510: E/AndroidRuntime(10976): Caused by: java.lang.IllegalStateException: attempt to re-open an already-closed object: android.database.sqlite.SQLiteQuery (mSql = SELECT * FROM Crataegus WHERE _id=?)
09-10 21:52:01.510: E/AndroidRuntime(10976): at android.database.sqlite.SQLiteClosable.acquireReference(SQLiteClosable.java:33)
09-10 21:52:01.510: E/AndroidRuntime(10976): at android.database.sqlite.SQLiteQuery.fillWindow(SQLiteQuery.java:82)
09-10 21:52:01.510: E/AndroidRuntime(10976): at android.database.sqlite.SQLiteCursor.fillWindow(SQLiteCursor.java:164)
09-10 21:52:01.510: E/AndroidRuntime(10976): at android.database.sqlite.SQLiteCursor.getCount(SQLiteCursor.java:156)
09-10 21:52:01.510: E/AndroidRuntime(10976): at android.widget.CursorAdapter.getCount(CursorAdapter.java:196)
09-10 21:52:01.510: E/AndroidRuntime(10976): at android.widget.ListView.setAdapter(ListView.java:467)
09-10 21:52:01.510: E/AndroidRuntime(10976): at android.app.ListActivity.setListAdapter(ListActivity.java:265)
09-10 21:52:01.510: E/AndroidRuntime(10976): at jem.danskflora.InitKeyActivity.onCreate(InitKeyActivity.java:30)
09-10 21:52:01.510: E/AndroidRuntime(10976): at android.app.Activity.performCreate(Activity.java:4562)
09-10 21:52:01.510: E/AndroidRuntime(10976): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1053)
09-10 21:52:01.510: E/AndroidRuntime(10976): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1934)
09-10 21:52:01.510: E/AndroidRuntime(10976): ... 11 more