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  • Exception: attempt to acquire a reference on a close SQLiteClosable

    - by CommonsWare
    I posted this back in May on the [android-developers] Google Group. I never heard back and was not able to reproduce the problem until one of my students did last week. I figured I'd post it here and see if it rang any bells for anyone. In one of my code samples, I have the following method: static Cursor getAll(SQLiteDatabase db, String orderBy) { return(db.rawQuery("SELECT * FROM restaurants "+orderBy, null)); } When I run it, sporadically, I get this: 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): java.lang.IllegalStateException: attempt to acquire a reference on a close SQLiteClosable 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteClosable.acquireReference(SQLiteClosable.java:31) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:56) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:49) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:49) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1118) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1092) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at apt.tutorial.Restaurant.getAll(Restaurant.java:14) This makes no sense to me. The database is definitely open. The SQLiteClosable is the SQLiteQuery created by SQLiteQueryDriver, and I see no evidence that there is an object pool or something going on here that might explain how a "new" SQLiteClosable is already closed. The fact that it is sporadic (meaning the same UI operations sometimes trigger the exception, but not always) suggests some sort of pool, race condition, or something...but I'm not sure where. Thoughts? Thanks! UPDATE: The code in question is from the LunchList tutorials out of my Android Programming Tutorials book. It's a bit spread out and not terribly suitable for posting directly in SO. You can download the code for that book from the above link if you want to take a look at it. I do not recall exactly which edition of the tutorial the student was working on at the time, though it was in the Tutorial 12-Tutorial 16 range. I was mostly hoping to run across somebody who had tripped over this problem before and had a likely culprit. I'm fairly certain my database is open. Thanks again!

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  • Tips for learning MUMPS (M) / Cache?

    - by Jake
    I'm interested in getting involved/up to speed on VistA, the Veterans' Administrations open source medical records system. To that effect, I understand I should learn the MUMPS (M) language upon which the software is based. Does anyone have any getting started tips or book recommendations on this language and environment? Any tips on getting up to speed on VistA is appreciated as well. Audience: experienced developer/consultant. Thanx in adv.

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  • Sealed alternative

    - by Jeriho
    According to "Programming in scala" a sealed class cannot have any new subclasses added except the ones in the same ?le. In the same book was described a way to enumerate classes that can extend class or trait in multiple files. I have forgotten it and can't find again. Remind it to me, please.

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  • Overwhelmed by design patterns... where to begin?

    - by Pete
    I am writing a simple prototype code to demonstrate & profile I/O schemes (HDF4, HDF5, HDF5 using parallel IO, NetCDF, etc.) for a physics code. Since focus is on IO, the rest of the program is very simple: class Grid { public: floatArray x,y,z; }; class MyModel { public: MyModel(const int &nip1, const int &njp1, const int &nkp1, const int &numProcs); Grid grid; map<string, floatArray> plasmaVariables; }; Where floatArray is a simple class that lets me define arbitrary dimensioned arrays and do mathematical operations on them (i.e. x+y is point-wise addition). Of course, I could use better encapsulation (write accessors/setters, etc.), but that's not the concept I'm struggling with. For the I/O routines, I am envisioning applying simple inheritance: Abstract I/O class defines read & write functions to fill in the "myModel" object HDF4 derived class HDF5 HDF5 using parallel IO NetCDF etc... The code should read data in any of these formats, then write out to any of these formats. In the past, I would add an AbstractIO member to myModel and create/destroy this object depending on which I/O scheme I want. In this way, I could do something like: myModelObj.ioObj->read('input.hdf') myModelObj.ioObj->write('output.hdf') I have a bit of OOP experience but very little on the Design Patterns front, so I recently acquired the Gang of Four book "Design Patterns: Elements of Reusable Object-Oriented Software". OOP designers: Which pattern(s) would you recommend I use to integrate I/O with the myModel object? I am interested in answering this for two reasons: To learn more about design patterns in general Apply what I learn to help refactor an large old crufty/legacy physics code to be more human-readable & extensible. I am leaning towards applying the Decerator pattern to myModel, so I can attach the I/O responsibilities dynamically to myModel (i.e. whether to use HDF4, HDF5, etc.). However, I don't feel very confident that this is the best pattern to apply. Reading the Gang of Four book cover-to-cover before I start coding feels like a good way to develop an unhealthy caffeine addiction. What patterns do you recommend?

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  • How can char* be a condition in for loop?

    - by Jackie
    In a book I am reading there is a piece of code : string x; size_t h=0; for(const char* s=x.ctr();*s;++s) h=(h*17)^*s; Regarding this code, I have two questions: how can *s be a condition? what does it mean? what does "h=(h*17)^*s" mean? Thanks for help!

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  • How to program and calculate multiple subtotal and grandtotal using jquery?

    - by Victor
    I'm stump figuring out how to do this in jquery, I need to do it without any plug-in. Imagine a shopping cart for books, each change of quantity (using select dropdown) will update the total price, grandtotal and then the hidden input value. <table> <tr> <td class="qty"> <select class="item-1"> <option value="1">1</option> <option value="2">2</option> <option value="3">3</option> ... </select> </td> <td class="product"> Book 1 </td> <td class="price-item-1"> $20 </td> <td class="total-item-1"> $20 </td> </tr> <tr> <td class="qty"> <select class="item-2"> <option value="1">1</option> <option value="2">2</option> <option value="3">3</option> ... </select> </td> <td class="product"> Book 2 </td> <td class="price-item-2"> $10 </td> <td class="total-item-2"> $10 </td> </tr> ... ... <tr> <td colspan="3" align="right"> <strong>Grand Total:</strong> </td> <td class="grandtotal"> </td> </tr> </table> <input type="hidden" id="qty-item-1" value="0" /> <input type="hidden" id="total-item-1" value="0" /> <input type="hidden" id="qty-item-2" value="0" /> <input type="hidden" id="total-item-2" value="0" />

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  • Beginner PHP Question

    - by user317128
    I am working on an example from a php book and am getting an error on line 8 with this code <?php $agent = getenv("HTTP_USER_AGENT"); if (preg_match("/MSIE/i", "$agent")); { $result = "You are using Microsoft Internet Explorer"; } else if (preg_match("/Mozilla/i", "$agent")); { $result = "You are using Mozilla firefox"; } else {$result = "you are using $agent"; } echo $result; ?>

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  • how to filter data from xml file for displaying only selected as nodes in treeview

    - by michale
    I have an xml file named "books.xml" provided in the link "http://msdn.microsoft.com/en-us/library/windows/desktop/ms762271(v=vs.85).aspx". What my requirement was to disaplay only the <title> from xml information as nodes in tree view. But when i did the following coding its displaying all the values as nodes like "catalog" as rootnode, book as parent node for all then author,title,genre etc as nodes but i want only root node catalogue and title as nodes not even book. Can any body guide me what modification i need to do in the exisitng logic for displaying title as nodes OpenFileDialog dlg = new OpenFileDialog(); dlg.Title = "Open XML document"; dlg.Filter = "XML Files (*.xml)|*.xml"; dlg.FileName = Application.StartupPath + "\\..\\..\\Sample.xml"; if (dlg.ShowDialog() == DialogResult.OK) { try { //Just a good practice -- change the cursor to a //wait cursor while the nodes populate this.Cursor = Cursors.WaitCursor; //First, we'll load the Xml document XmlDocument xDoc = new XmlDocument(); xDoc.Load(dlg.FileName); //Now, clear out the treeview, //and add the first (root) node treeView1.Nodes.Clear(); treeView1.Nodes.Add(new TreeNode(xDoc.DocumentElement.Name)); TreeNode tNode = new TreeNode(); tNode = (TreeNode)treeView1.Nodes[0]; //We make a call to addTreeNode, //where we'll add all of our nodes addTreeNode(xDoc.DocumentElement, tNode); //Expand the treeview to show all nodes treeView1.ExpandAll(); } catch (XmlException xExc) //Exception is thrown is there is an error in the Xml { MessageBox.Show(xExc.Message); } catch (Exception ex) //General exception { MessageBox.Show(ex.Message); } finally { this.Cursor = Cursors.Default; //Change the cursor back } }} //This function is called recursively until all nodes are loaded private void addTreeNode(XmlNode xmlNode, TreeNode treeNode) { XmlNode xNode; TreeNode tNode; XmlNodeList xNodeList; if (xmlNode.HasChildNodes) //The current node has children { xNodeList = xmlNode.ChildNodes; for (int x = 0; x <= xNodeList.Count - 1; x++) //Loop through the child nodes { xNode = xmlNode.ChildNodes[x]; treeNode.Nodes.Add(new TreeNode(xNode.Name)); tNode = treeNode.Nodes[x]; addTreeNode(xNode, tNode); } } else //No children, so add the outer xml (trimming off whitespace) treeNode.Text = xmlNode.OuterXml.Trim(); }

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  • Access Iphone Pim Data via web app

    - by Eric
    i think i know the answer to this question, but just want to make sure before i dismiss the possibility. is it possible with user permission for my web app to access pim data like the address book on a iphone, similar to how a web app can access the location service?

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  • iPhone: How to Trigger the Loading of a View Using a UI Element in a Previous View

    - by Kevin Horvath
    I've been reading the Head First iPhone Development book and I understand how to get to a new view from a table but how exactly would I be able to get to a new view or view controller, by just simply pressing a button? Is that even possible? I mean there are some apps where you click a button, not a table cell and it loads a new view. How exactly is that done? If someone could help out a newbie it would be greatly appreciated!

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  • How to crop scanned image using C#?

    - by ieaglle
    I have a scanned image of a book page and i need to crop this scan for leaving only page area. I tried to use AForge to detect page borders, but it doesn't work because the space which i need to crop may consist of little "light" areas (due to scanner quality) and edge detector detects borders there. That's why this is bad idea as for me. Could you recommend something? P.S. Please don't tell me to use non-free libraries.

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  • rewrite rule is not working in .htaccess file

    - by deepu sankar
    in my portal i call a pdf file, path looks like http://www.mysite.com/filespath/books/online_bliss_in_five_simple_steps_1339668056/live/online_dating_bliss_in_five_simple_steps_1339668056.php for user acceptance i need to reduce this url. then i add a code in .htaccess file. after adding this line only a white page is displaying when i call my portal the code is RewriteEngine On RewriteRule ^book/([A-Za-z0-9-]+_.)/?$ /live/$1.php [NC,L] please help me

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  • How to develop a client-server seat booking program via java socket programming ?

    - by Haxed
    I have a project to develop a client server application in java. This is to be done using socket programming. Our lecturer, used 2 files, the TCPClient.java and TCPServer.java, to make a connection and we typed "Hi" in the client and the server displayed that message. I need to develop a seat booking application. Any suggestions for tutorials or tips or a book perhaps would be nice. Many Thanks

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  • Communicating with remote server in Android

    - by primal
    Hi, As part of the college mini-project, I am developing a micro-blogging platform for Android. I am planning to use Django framework in python to handle the communication between Android and remote server so as to make database API independent. I heard its best practice to use HTTP methods for the communication. Which is the best site/book to learn using HTTP methods for Android? I

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  • C++ adding friend to a template class in order to typecast

    - by user1835359
    I'm currently reading "Effective C++" and there is a chapter that contains code similiar to this: template <typename T> class Num { public: Num(int n) { ... } }; template <typename T> Num<T> operator*(const Num<T>& lhs, const Num<T>& rhs) { ... } Num<int> n = 5 * Num<int>(10); The book says that this won't work (and indeed it doesn't) because you can't expect the compiler to use implicit typecasting to specialize a template. As a soluting it is suggested to use the "friend" syntax to define the function inside the class. //It works template <typename T> class Num { public: Num(int n) { ... } friend Num operator*(const Num& lhs, const Num& rhs) { ... } }; Num<int> n = 5 * Num<int>(10); And the book suggests to use this friend-declaration thing whenever I need implicit conversion to a template class type. And it all seems to make sense. But why can't I get the same example working with a common function, not an operator? template <typename T> class Num { public: Num(int n) { ... } friend void doFoo(const Num& lhs) { ... } }; doFoo(5); This time the compiler complaints that he can't find any 'doFoo' at all. And if i declare the doFoo outside the class, i get the reasonable mismatched types error. Seems like the "friend ..." part is just being ignored. So is there a problem with my understanding? What is the difference between a function and an operator in this case?

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