我使用光标从数据库中获取了记录.这是完美的工作.但是,当我使用这个代码时,我在Logcat中有一些错误
public Cursor fetchAll()
{
sqliteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(t1,new String[] {"_id",name,date,prior,time,dateformat},null,prior);
return cursor;
}
我的logcat是 –
12-16 14:49:20.774: E/Database(18611): close() was never explicitly called on database '/data/data/com.android.application/databases/appZ.db' 12-16 14:49:20.774: E/Database(18611): android.database.sqlite.DatabaSEObjectNotClosedException: Application did not close the cursor or database object that was opened here 12-16 14:49:20.774: E/Database(18611): at android.database.sqlite.sqliteDatabase.<init>(sqliteDatabase.java:1810) 12-16 14:49:20.774: E/Database(18611): at android.database.sqlite.sqliteDatabase.openDatabase(sqliteDatabase.java:817) 12-16 14:49:20.774: E/Database(18611): at android.database.sqlite.sqliteDatabase.openOrCreateDatabase(sqliteDatabase.java:851) 12-16 14:49:20.774: E/Database(18611): at android.database.sqlite.sqliteDatabase.openOrCreateDatabase(sqliteDatabase.java:844) 12-16 14:49:20.774: E/Database(18611): at android.app.ContextImpl.openOrCreateDatabase(ContextImpl.java:540) 12-16 14:49:20.774: E/Database(18611): at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:203) 12-16 14:49:20.774: E/Database(18611): at android.database.sqlite.sqliteOpenHelper.getWritableDatabase(sqliteOpenHelper.java:98) 12-16 14:49:20.774: E/Database(18611): at android.database.sqlite.sqliteOpenHelper.getReadableDatabase(sqliteOpenHelper.java:158) 12-16 14:49:20.774: E/Database(18611): at com.android.todoapplication.DBHelper.fetchAll(DBHelper.java:91) 12-16 14:49:20.774: E/Database(18611): at com.android.todoapplication.ApplicationActivity.sc_adapter(ApplicationActivity.java:1210) 12-16 14:49:20.774: E/Database(18611): at com.android.todoapplication.ApplicationActivity.refresh_data(ApplicationActivity.java:1195) 12-16 14:49:20.774: E/Database(18611): at com.android.todoapplication.ApplicationActivity.onKeyDown(ApplicationActivity.java:1440) 12-16 14:49:20.774: E/Database(18611): at android.view.KeyEvent.dispatch(KeyEvent.java:1037) 12-16 14:49:20.774: E/Database(18611): at android.app.Activity.dispatchKeyEvent(Activity.java:2068) 12-16 14:49:20.774: E/Database(18611): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1643) 12-16 14:49:20.774: E/Database(18611): at android.view.ViewRoot.deliverKeyEventToViewHierarchy(ViewRoot.java:2471) 12-16 14:49:20.774: E/Database(18611): at android.view.ViewRoot.handleFinishedEvent(ViewRoot.java:2441) 12-16 14:49:20.774: E/Database(18611): at android.view.ViewRoot.handleMessage(ViewRoot.java:1735) 12-16 14:49:20.774: E/Database(18611): at android.os.Handler.dispatchMessage(Handler.java:99) 12-16 14:49:20.774: E/Database(18611): at android.os.Looper.loop(Looper.java:123) 12-16 14:49:20.774: E/Database(18611): at android.app.ActivityThread.main(ActivityThread.java:4627) 12-16 14:49:20.774: E/Database(18611): at java.lang.reflect.Method.invokeNative(Native Method) 12-16 14:49:20.774: E/Database(18611): at java.lang.reflect.Method.invoke(Method.java:521) 12-16 14:49:20.774: E/Database(18611): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 12-16 14:49:20.774: E/Database(18611): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 12-16 14:49:20.774: E/Database(18611): at dalvik.system.NativeStart.main(Native Method)
我从here提到了一些东西.他们告诉使用getReadableDatabase().我也使用该方法.而且,我也使用这种方法,
public Cursor fetchAll()
{
sqliteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(t1,prior);
if (cursor!=null)
{
cursor.close();
}
if (db!=null)
{
db.close();
}
return cursor;
}
之后有错误 –
Database wasn't open.
解决方法
编辑：如果返回已经关闭的游标,则无法使用.在调用方法之前打开数据库,然后在调用该方法后关闭游标,然后关闭数据库.
完成后可以关闭光标,如下所示：
Cursor cursor = fetchAll(); ... // Do your work with the cursor cursor.close();
或者如果您使用活动中的游标,并且需要重新排序(活动重新启动,停止…),您可以使用以下命令：
Cursor cursor = fetchAll(); startManagingCursor(cursor); // Android will take care of the cursor for you // Do your work with the cursor
关闭数据库(关闭游标后,或者最好在onDestroy()中的活动内)：
dbhelper.close();
