Android错误:由于连接池已closures,无法执行此操作

我已经searchStackOverflow和networking为这个问题的答案,但我找不到答案。 当我在姜饼上运行我的应用程序,它运行良好。 但是当我在4.2.2上运行它,我得到这个错误: java.lang.IllegalStateException Cannot perform this operation because the connection pool has been closed我有一个SherlockFragmentActivity它包含两个片段。

片段1:

 public final class TodoFragment extends SherlockListFragment { NotesDbAdapter db; private static final int DELETE_ID = Menu.FIRST + 1; public static TodoFragment newInstance(String s) { TodoFragment fragment = new TodoFragment(); return fragment; } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); db = new NotesDbAdapter(getActivity()); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { if (container == null) { return null; } return ll; } 

片段2:

 public final class NotesFragment extends SherlockListFragment { NotesDbAdapter db; private static final int ACTIVITY_EDIT = 1; private static final int DELETE_ID = Menu.FIRST + 1; public static NotesFragment newInstance(String content) { NotesFragment fragment = new NotesFragment(); return fragment; } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); db = new NotesDbAdapter(getActivity()); db.open(); if (db.fetchAllNotes().getCount() == 0) { doWelcomeMessage(); } db.close(); } private void doWelcomeMessage() { // Show welcome dialog startActivity(new Intent(getActivity(), NotesWelcome.class)); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { if (container == null) { return null; } db = new NotesDbAdapter(getActivity()); db.open(); if (db.fetchAllNotes().getCount() == 0) { doWelcomeMessage(); } db.close(); return ll; } 

SherlockFragmentActivity:

 public class NotesFragmentActivity extends SherlockFragmentActivity { ViewPager mViewPager; TabsAdapter mTabsAdapter; TextView tabCenter; TextView tabText; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); mViewPager = new ViewPager(this); mViewPager.setId(R.id.pager); setContentView(mViewPager); ActionBar bar = getSupportActionBar(); bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS); mTabsAdapter = new TabsAdapter(this, mViewPager); mTabsAdapter.addTab(bar.newTab().setText("Notes"), NotesFragment.class, null); mTabsAdapter.addTab(bar.newTab().setText("Todo List"), TodoFragment.class, null); } public static class TabsAdapter extends FragmentPagerAdapter implements ActionBar.TabListener, ViewPager.OnPageChangeListener { private final Context mContext; private final ActionBar mActionBar; private final ViewPager mViewPager; private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>(); static final class TabInfo { private final Class<?> clss; private final Bundle args; TabInfo(Class<?> _class, Bundle _args) { clss = _class; args = _args; } } public TabsAdapter(SherlockFragmentActivity activity, ViewPager pager) { super(activity.getSupportFragmentManager()); mContext = activity; mActionBar = activity.getSupportActionBar(); mViewPager = pager; mViewPager.setAdapter(this); mViewPager.setOnPageChangeListener(this); } public void addTab(ActionBar.Tab tab, Class<?> clss, Bundle args) { TabInfo info = new TabInfo(clss, args); tab.setTag(info); tab.setTabListener(this); mTabs.add(info); mActionBar.addTab(tab); notifyDataSetChanged(); } @Override public int getCount() { return mTabs.size(); } @Override public Fragment getItem(int position) { TabInfo info = mTabs.get(position); return Fragment.instantiate(mContext, info.clss.getName(), info.args); } public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { } public void onPageSelected(int position) { mActionBar.setSelectedNavigationItem(position); } public void onPageScrollStateChanged(int state) { } public void onTabSelected(Tab tab, FragmentTransaction ft) { Object tag = tab.getTag(); for (int i = 0; i < mTabs.size(); i++) { if (mTabs.get(i) == tag) { mViewPager.setCurrentItem(i); } } } public void onTabUnselected(Tab tab, FragmentTransaction ft) { } public void onTabReselected(Tab tab, FragmentTransaction ft) { } } } 

我一直坚持这个小时 (没有笑话),并会非常感激任何帮助。 再次感谢

Solutions Collecting From Web of "Android错误:由于连接池已closures,无法执行此操作"

Android 4.1之后添加了SQLiteConnectionPooling。 而在以前的版本中,如果在closures的连接上执行查询或其他操作时,游标对象将尝试重新打开数据库,而使用连接池(Connection Pooling)引发exception。 NotesDBAdapter可能是一个倒退,它可能与4.2.2兼容。

我得到了同样的问题,因为多个线程访问相同的SQLiteOpenHelper ,因此同时打开和closures连接。

我通过向帮助程序添加userCount属性来解决此问题。 现在,助手只closures连接,如果userCount为零,即没有其他线程正在使用数据库。