android在意图之间传递数据助手

Question

我得到"应用程序没有关闭在此处打开的游标或数据库对象"错误，所以我决定在意图之间传递datahelper，而不是为每个意图关闭/打开数据库。。

我试着加入Extras，但没有成功。。。

谢谢你的帮助

this.dhn=新的DataHelper（this）；

public void StartGame(View v) { 
Intent intent = new Intent(StartScreen.this, Game.class); 
intent.putExtra("dhn",this.dhn); 
startActivity(intent); 
}

Answer 1

我将DataHelper更改为Singleton，看起来可以在没有新助手的情况下从任何其他意图使用。。看起来目前有效。将测试更多

    private static DataHelper singleton;
    public static DataHelper getDataHelper(Context context) {
            if (singleton == null) {
                    singleton = new DataHelper(context);
                    OpenHelper openHelper = new OpenHelper(singleton.context);
                    singleton.db = openHelper.getWritableDatabase();
            }
            if(!singleton.db.isOpen()){
                    OpenHelper openHelper = new OpenHelper(singleton.context);
                    singleton.db = openHelper.getWritableDatabase();
            }
            singleton.context = context;
            return singleton;
    }
    private DataHelper(Context context) {
        this.context = context;
}

Answer 2

这就是我在代码中处理问题的方法：

public class DataOpenHelper extends SQLiteOpenHelper
{
    private static Object lock = new Object();
    private static DataOpenHelper inst = null;
    private static Context nextContext = null;
    private DataOpenHelper()
    {
        super(nextContext);
        nextContext = null;
    }
    public static void registerContext(Context ctx)
    {
        synchronized (lock)
        {
            nextContext = ctx;
        }
    }
    public static DataOpenHelper getInstance() throws ContextNotRegisteredException
    {
        if (inst == null)
        {
            synchronized (lock)
            {
                if (inst == null)
                {
                    if (nextContext == null)
                    {
                        throw new ContextNotRegisteredException();
                    }
                    inst = new DataOpenHelper();
                }
            }
        }
    }
}
    public class ContextNotRegisteredException extends Exception{};