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  • How to run a long task in backgroung in iOS applications?

    - by John Canady
    I am developing an application which requires running a task in background. I am trying this by calling a method which will retrieve(download) data from web server through web services. this method will call some more methods which are in different view controller classes. Here when I tap on home button of device, the method is calling but no further execution of the remaining code. This is the code I have written in (void)applicationDidEnterBackground:(UIApplication )application { UIApplication app = [UIApplication sharedApplication]; UIBackgroundTaskIdentifier bgTask = 0; bgTask = [app beginBackgroundTaskWithExpirationHandler:^{ [app endBackgroundTask:bgTask]; bgTask = UIBackgroundTaskInvalid; }]; // Start the long-running task and return immediately. dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ // Do the work associated with the task. NSString *updatekey = [[NSUserDefaults standardUserDefaults] objectForKey:@"updatesetting"]; if([updatekey isEqualToString:@"enabled"]) { DataSettingsView *periodicUpdate = [[DataSettingsView alloc] init]; [periodicUpdate updateDataPeriodically]; //[periodicUpdate viewDidLoad]; //[periodicUpdate release]; } [app endBackgroundTask:bgTask]; bgTask = UIBackgroundTaskInvalid; }); } some one please help me in this background execution of long tasks with some example of code. Some help will appreciated and helpful to me.

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  • How do i integrate paypal in my website? Java

    - by Nitesh Panchal
    Hello, I want to integrate paypal in my java web application. I saw that they offer many methods to accomplish this. But i want my visitors to remain on my site only. My friend told me that Paypal offers webservice. But i can't seem to find any documentation on Paypal site. If anybody could help me with this, i would be really very grateful. Please offer me the relevant links on Paypal where i could read and get my things done. Secondly, my friend also told me that we need to give location to paypal where my visitors would be redirected once paypal payment is complete. But i am confused. I am working on localhost. How would Paypal know about my localhost? I have already created my sandbox testing account. What should be my next step. Please explain me in detail. I don't know anything about Paypal. Once i created a demo application of Express checkout where they give a simple button of Pay Now and on clicking on it shopping cart etc appears. But now i want my visitors to stay on same website. Thanks in advance :)

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  • C++ destructor problem with boost::scoped_ptr

    - by bb-generation
    I have a question about the following code: #include <iostream> #include <boost/scoped_ptr.hpp> class Interface { }; class A : public Interface { public: A() { std::cout << "A()" << std::endl; } virtual ~A() { std::cout << "~A()" << std::endl; } }; Interface* get_a() { A* a = new A; return a; } int main() { { std::cout << "1" << std::endl; boost::scoped_ptr<Interface> x(get_a()); std::cout << "2" << std::endl; } std::cout << "3" << std::endl; } It creates the following output: 1 A() 2 3 As you can see, it doesn't call the destructor of A. The only way I see to get the destructor of A being called, is to add a destructor for the Interface class like this: virtual ~Interface() { } But I really want to avoid any Implementation in my Interface class and virtual ~Interface() = 0; doesn't work (produces some linker errors complaining about a non existing implementation of ~Interface(). So my question is: What do I have to change in order to make the destructor being called, but (if possible) leave the Interface as an Interface (only abstract methods).

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  • In R, how to get powers of ten in bold font in a plot label?

    - by wfoolhill
    I want to have "10^4 points" in bold as my x-axis label. I know how to make a simple label in bold: plot(1:10, xlab="") mtext(text="10 points", side=1, font=2, line=3) Thanks to this answer, I know how to make a label with a power of ten but nothing is in bold: mtext(text=expression(paste(10^4, " points")), side=1, font=2, line=3) Thanks to this answer, I also know how to make a label with a Greek letter in bold: mtext(text=expression(bold(paste(beta, "=", 10^1, " points"))), side=1, line=3) But still the power of ten is not in bold! It doesn't work either with bquote: mtext(text=bquote(bold(10^1~points)), side=1, line=3) Any idea? Here are some details about my system. Let me know if you need anything else. > sessionInfo() R version 2.15.0 (2012-03-30) Platform: x86_64-redhat-linux-gnu (64-bit) locale: [1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C [3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8 [5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8 [7] LC_PAPER=C LC_NAME=C [9] LC_ADDRESS=C LC_TELEPHONE=C [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C attached base packages: [1] stats graphics grDevices utils datasets methods base

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  • unresolved token/symbol in MC++ wrapper class calling native code

    - by rediVider
    I'm new to MC++ and have basically no idea what's going on yet. In trying to get this working i've determined many things that don't work, i'm just looking for one of the ways that will work. I have a mc++ class as follows that seems to have to be a "ref" class to allow me to see any methods/properties. public ref class EmCeePlusPlus { static void Open(void) { Testor* t = new Testor(); Testor::Open(); }; }; extern public class Testor { public: Testor() { }; static void Open(void) { int x = 3; int xx = cli_lock(x); }; }; Now, the only reason i created the class Testor, and moved the call to cli_open to it, is because i was getting a unresolved external symbol if i put the same call in the ref class. In this current code, however, I get an uresolved token error and unresolved symbol error ONLY if i have the call to Testor::Open(). If that line is commented then it compiles fine. As it is I get the errors below. cli_lock() is native code that is able to be called externally by other native DLLs with not problems. Any ideas where i should be looking? error LNK2028: unresolved token (0A000056) "extern "C" int __cdecl cli_lock(int)" (?cli_lock@@$$J0YAHH@Z) referenced in function "public: static void __cdecl Giga::Testor::Open(void)" (?Open@Testor@Giga@@$$FSAXXZ) error LNK2019: unresolved external symbol "extern "C" int __cdecl cli_lock(int)" (?cli_lock@@$$J0YAHH@Z) referenced in function "public: static void __cdecl Giga::Testor::Open(void)" (?Open@Testor@Giga@@$$FSAXXZ)

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  • c++ templates and inheritance

    - by Armen Ablak
    Hey, I'm experiencing some problems with breaking my code to reusable parts using templates and inheritance. I'd like to achieve that my tree class and avltree class use the same node class and that avltree class inherits some methods from the tree class and adds some specific ones. So I came up with the code below. Compiler throws an error in tree.h as marked below and I don't really know how to overcome this. Any help appreciated! :) node.h: #ifndef NODE_H #define NODE_H #include "tree.h" template <class T> class node { T data; ... node() ... friend class tree<T>; }; #endif tree.h #ifndef DREVO_H #define DREVO_H #include "node.h" template <class T> class tree { public: //signatures tree(); ... void insert(const T&); private: node<T> *root; //missing type specifier - int assumed. Note: C++ does not support default-int }; //implementations #endif avl.h #ifndef AVL_H #define AVL_H #include "tree.h" #include "node.h" template <class T> class avl: public tree<T> { public: //specific int findMin() const; ... protected: void rotateLeft(node<T> *)const; private: node<T> *root; }; #endif avl.cpp (I tried separating headers from implementation, it worked before I started to combine avl code with tree code) #include "drevo" #include "avl.h" #include "vozlisce.h" template class avl<int>; //I know that only avl with int can be used like this, but currently this is doesn't matter :) //implementations ...

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  • Best "Loading" feedback for ASP.Net?

    - by IP
    So, we have an ASP.Net application - fairly standard - and in there are lots of updatepanels, and postbacks. On some pages we have <ajax:UpdatePanelAnimationExtender ID="ae" runat="server" TargetControlID="updatePanel" BehaviorID="UpdateAnimation"> <Animations> <OnUpdating> <FadeOut Duration="0.1" minimumOpacity=".3" /> </OnUpdating> <OnUpdated> <FadeIn minimumOpacity=".5" Duration="0" /> </OnUpdated> </Animations> </ajax:UpdatePanelAnimationExtender> Which basically whites out the page when a postback is going on (but this clashes with modal dialog grey backgrounds). In some cases we have a progressupdate control which just has a spinny icon in the middle of the page. But none of them seem particularly nice and all a bit clunky. They also require a lot of code in various places around the app. What methods do other people use and find effective?

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  • Converting string to a simple type

    - by zespri
    .Net framework contains a great class named Convert that allows conversion between simple types, DateTime type and String type. Also the class support conversion of the types implementing IConvertible interface. The class has been implemented in the very first version of .Net framework. There were a few things in the first .Net framework that were not done quite right. For example .Parse methods on simple types would throw an exception if the string couldn't be parsed and there would be no way to check if exception is going to be thrown in advance. A future version of .Net Framework removed this deficiency by introducing the TryParse method that resolved this problem. The Convert class dates back to time of the old Parse method, so the ChangeType method on this class in implemented old style - if conversion can't be performed an exception is thrown. Take a look at the following code: public static T ConvertString<T>(string s, T @default) { try { return (T)Convert.ChangeType(s, typeof(T), CultureInfo.InvariantCulture); } catch (Exception) { return @default; } } This code basically does what I want. However I would pretty much like to avoid the ugly try/catch here. I'm sure, that similar to TryParse, there is a modern method of rewriting this code without the catch-all. Could you suggest one?

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  • Segmentation Fault when trying to push a string to the back of a list.

    - by user308012
    I am trying to write a logger class for my C++ calculator, but I'm experiencing a problem while trying to push a string into a list. I have tried researching this issue and have found some information on this, but nothing that seems to help with my problem. I am using a rather basic C++ compiler, with little debugging utilities and I've not used C++ in quite some time (even then it was only a small amount). My code: #ifndef _LOGGER_H_ #define _LOGGER_H_ #include <iostream> #include <list> #include <string> using std::cout; using std::cin; using std::endl; using std::list; using std::string; class Logger { private: list<string> *mEntries; public: Logger() { // Initialize the entries list mEntries = new list<string>(); } ~Logger() { // Release the list mEntries->clear(); delete mEntries; } // Public Methods void WriteEntry(string entry) { // *** BELOW LINE IS MARKED WITH THE ERROR *** mEntries->push_back(string(entryData)); } void DisplayEntries() { cout << endl << "**********************" << endl << "* Logger Entries *" << endl << "**********************" << endl << endl; for(list<string>::iterator it = mEntries->begin(); it != mEntries->end(); it++) { cout << *it << endl; } } }; #endif I am calling the WriteEntry method by simply passing in a string, like so: mLogger->WriteEntry("Testing"); Any advice on this would be greatly appreciated.

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  • Efficient database access when dealing with multiple abstracted repositories

    - by Nathan Ridley
    I want to know how most people are dealing with the repository pattern when it involves hitting the same database multiple times (sometimes transactionally) and trying to do so efficiently while maintaining database agnosticism and using multiple repositories together. Let's say we have repositories for three different entities; Widget, Thing and Whatsit. Each repository is abstracted via a base interface as per normal decoupling design processes. The base interfaces would then be IWidgetRepository, IThingRepository and IWhatsitRepository. Now we have our business layer or equivalent (whatever you want to call it). In this layer we have classes that access the various repositories. Often the methods in these classes need to do batch/combined operations where multiple repositories are involved. Sometimes one method may make use of another method internally, while that method can still be called independently. What about, in this scenario, when the operation needs to be transactional? Example: class Bob { private IWidgetRepository _widgetRepo; private IThingRepository _thingRepo; private IWhatsitRepository _whatsitRepo; public Bob(IWidgetRepository widgetRepo, IThingRepository thingRepo, IWhatsitRepository whatsitRepo) { _widgetRepo = widgetRepo; _thingRepo= thingRepo; _whatsitRepo= whatsitRepo; } public void DoStuff() { _widgetRepo.StoreSomeStuff(); _thingRepo.ReadSomeStuff(); _whatsitRepo.SaveSomething(); } public void DoOtherThing() { _widgetRepo.UpdateSomething(); DoStuff(); } } How do I keep my access to that database efficient and not have a constant stream of open-close-open-close on connections and inadvertent invocation of MSDTS and whatnot? If my database is something like SQLite, standard mechanisms like creating nested transactions are going to inherently fail, yet the business layer should not have to be concerning itself with such things. How do you handle such issues? Does ADO.Net provide simple mechanisms to handle this or do most people end up wrapping their own custom bits of code around ADO.Net to solve these types of problems?

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  • How to call a generic method with an anonymous type involving generics?

    - by Alex Black
    I've got this code that works: def testTypeSpecialization = { class Foo[T] def add[T](obj: Foo[T]): Foo[T] = obj def addInt[X <% Foo[Int]](obj: X): X = { add(obj) obj } val foo = addInt(new Foo[Int] { def someMethod: String = "Hello world" }) assert(true) } But, I'd like to write it like this: def testTypeSpecialization = { class Foo[T] def add[X, T <% Foo[X](obj: T): T = obj val foo = add(new Foo[Int] { def someMethod: String = "Hello world" }) assert(true) } This second one fails to compile: no implicit argument matching parameter type (Foo[Int]{ ... }) = Foo[Nothing] was found. Basically: I'd like to create a new anonymous class/instance on the fly (e.g. new Foo[Int] { ... } ), and pass it into an "add" method which will add it to a list, and then return it The key thing here is that the variable from "val foo = " I'd like its type to be the anonymous class, not Foo[Int], since it adds methods (someMethod in this example) Any ideas? I think the 2nd one fails because the type Int is being erased. I can apparently 'hint' the compiler like this: def testTypeSpecialization = { class Foo[T] def add[X, T <% Foo[X]](dummy: X, obj: T): T = obj val foo = add(2, new Foo[Int] { def someMethod: String = "Hello world" }) assert(true) }

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  • Initializing own plugins

    - by jgauffin
    I've written a few jquery plugins for my client. I want to write a function which would initialize each plugin which have been loaded. Example: <script src="/Scripts/jquery.plugin1.min.js")" type="text/javascript"></script> <script src="/Scripts/jquery.plugin2.min.js")" type="text/javascript"></script> <script src="/Scripts/jquery.initializer.min.js")" type="text/javascript"></script> Here I've loaded plugin1 and plugin2. Plugin1 should be attached to all links with class name 'ajax' and plugin2 to all divs with class name 'test2': $('document').ready(function(){ $('a.ajax').plugin1(); $('div.test2').plugin2(); } I know that I can use jQuery().pluginName to check if a plugin exists. But I want to have a leaner way. Can all loaded plugins register a initialize function in an array or something like that which I in document.ready can iterate through and invoke? like: //in plugin1.js myCustomPlugins['plugin1'] = function() { $('a.ajax').plugin1(); }; // and in the initializer script: myCustomPlugins.each(function() { this(); }; Guess it all boiled down to three questions: How do I use a jquery "global" array? How do I iterate through that array to invoke registered methods Are there a better approach?

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  • C++, generic programming and virtual functions. How do I get what I want?

    - by carleeto
    This is what I would like to do using templates: struct op1 { virtual void Method1() = 0; } ... struct opN { virtual void MethodN() = 0; } struct test : op1, op2, op3, op4 { virtual void Method1(){/*do work1*/}; virtual void Method2(){/*do work2*/}; virtual void Method3(){/*do work3*/}; virtual void Method4(){/*do work4*/}; } I would like to have a class that simply derives from a template class that provides these method declarations while at the same time making them virtual. This is what I've managed to come up with: #include <iostream> template< size_t N > struct ops : ops< N - 1 > { protected: virtual void DoStuff(){ std::cout<<N<<std::endl; }; public: template< size_t i > void Method() { if( i < N ) ops<i>::DoStuff(); } //leaving out compile time asserts for brevity } struct test : ops<6> { }; int main( int argc, char ** argv ) { test obj; obj.Method<3>(); //prints 3 return 0; } However, as you've probably guessed, I am unable to override any of the 6 methods I have inherited. I'm obviously missing something here. What is my error? No, this isn't homework. This is curiosity.

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  • How to insert several thousand columns into sqlite3?

    - by user291071
    Similar to my last question, but I ran into problem lets say I have a simple dictionary like below but its Big, when I try inserting a big dictionary using the methods below I get operational error for the c.execute(schema) for too many columns so what should be my alternate method to populate an sql databases columns? Using the alter table command and add each one individually? import sqlite3 con = sqlite3.connect('simple.db') c = con.cursor() dic = { 'x1':{'y1':1.0,'y2':0.0}, 'x2':{'y1':0.0,'y2':2.0,'joe bla':1.5}, 'x3':{'y2':2.0,'y3 45 etc':1.5} } # 1. Find the unique column names. columns = set() for _, cols in dic.items(): for key, _ in cols.items(): columns.add(key) # 2. Create the schema. col_defs = [ # Start with the column for our key name '"row_name" VARCHAR(2) NOT NULL PRIMARY KEY' ] for column in columns: col_defs.append('"%s" REAL NULL' % column) schema = "CREATE TABLE simple (%s);" % ",".join(col_defs) c.execute(schema) # 3. Loop through each row for row_name, cols in dic.items(): # Compile the data we have for this row. col_names = cols.keys() col_values = [str(val) for val in cols.values()] # Insert it. sql = 'INSERT INTO simple ("row_name", "%s") VALUES ("%s", "%s");' % ( '","'.join(col_names), row_name, '","'.join(col_values) )

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  • iPhone Custom CA certificate for an application which uses NSURLConnection?

    - by jr
    I have an application which is communicating with many different sites and each site has its own SSL certificate signed by our own internal CA. Doing this prevents us the need from purchasing SSL certificates for each site (hundreds or thousands) and is more secure then using a wildcard certificate with a shared key on each of those sites. So, basically using a CA certificate is the only way. Right now, I have a mobileprovision file which will install the CA certificate as a profile on the phone. When our iPhone application launches if it gets an SSL Certificate error it redirects to a this mobile provision file via Safari and the user will be prompted to install the CA. The problem is that I am concerned that the Apple AppStore might deny my app for doing this (Just some feedback from other developers at this point), and I wanted to research other ways to accomplish this. Basically what I need to accomplish is allow an SSL connection which will verify against a custom CA certificate which will be embedded in my application. This will make the CA certificate active for only the calls I make. I am using the standard NSURLConnection methods in order to communicate with the service. Is this possible? Can someone show me how to load the CA (what form PEM?) and add it to the list of trusted CA certificates for my application? If that is not possible what other options do I have? Just trusting all certificates isn't really any option, we want to prevent man in the middle attacks and only trust our CA issued certificates. Thanks!

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  • General web service ideas

    - by user2014175
    I have a question regarding different types of web services. I'll preface this by saying that I have built a number of apps (for both ios and android) for personal use that interact with the web via php and sql. I have taught myself these languages, and as such don't have the broader background knowledge that many of you do. My question is, in what other ways can you perform an interaction between a web service and a mobile device other than mobile - php - sql - etc. For example, If I built a very simple tracking app for my car, my current method would be to push GPS coordinates from my iphone to my database at a set interval, then I would write a simple bit of javascript that pulled those coordinates out of the database and superimposed them on a google map. Is there a different way to do this? Such as the server acting as a live middle man who simple pushed the coordinates directly to a target browser? Without the database in the middle? If so, are there advantages and disadvantages to these different methods to achieve different goals? I know its a broad question but I'm really intrigued and I'm finding it difficult to word a google search for it. Any info / reading material suggesting would be excellent. Thanks

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  • iOS6: do we have to set rootViewController in App delegate in order to support different orientations?

    - by Centurion
    The app was perfectly fine working in iOS5 in landscape orientation. However in iOS6, it started to use portrait orientation in all view controllers. The methods shouldAutorotateToInterfaceOrientation are not called anymore. I read the new stuff about changed rotation mechanism in iOS6 and I was able to fix that by adding a line in my AppDelegate: self.window.rootViewController = _viewController _viewControler is the starting screen (Home-menu). All other view controllers implement shouldAutorotateToInterfaceOrientation method and returns YES for landscape orientations only. So, it's perfectly working solution for the app that needs to support only one orientation. However, the problem is I need one view controller (lets call it phone-VC) to be presented in portrait orientation. Now, if I want this view controller would be rotated then I need to return YES in Home-menu controller that is assigned to rootViewControler in appDelegate. However, I can't do that because this rootViewController is starting window that need to presented in landscape only, otherwise the layout with graphics in this window will break. But if I don't return YES from its shouldAutorotateToInterfaceOrientation (Home-menu) then the same method is not called in my view phone-VC that needs to be presented in portrait. Any ideas? Does the assignation of rootViewController is mandatory in AppDelegate? UPDATE: the problem exists on device (at least on iPhone4).

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  • Working with PHP and MySQL - need a good and secure design with OO design

    - by Andrew
    I am new to PHP- first time developer. I am working on my web application and it is nearly done; nevertheless, most of my sql was done directly via code using direct mysql requests. This is the way I approached it: In classes_db.php I declared the db settings and created methods that I use to open and close DB connections. I declare those objects on my regular pages: class classes_db { public $dbserver = 'server; public $dbusername = 'user'; public $dbpassword = 'pass'; public $dbname = 'db'; function openDb() { $dbhandle = mysql_connect($this->dbserver, $this->dbusername, $this->dbpassword); if (!$dbhandle) { die('Could not connect: ' . mysql_error()); } $selected = mysql_select_db($this->dbname, $dbhandle) or die("Could not select the database"); return $dbhandle; } function closeDb($con) { mysql_close($con); } } On my regular page, I do this: <?php require 'classes_db.php'; session_start(); //create instance of the DB class $db = new classes_db(); //get dbhandle $dbhandle = $db->openDb(); //process query $result = mysql_query("update user set username = '" . $usernameFromForm . "' where iduser= " . $_SESSION['user']->iduser); //close the connection if (isset($dbhandle)) { $db->closeDb($dbhandle); } ?> My questions is: how to do it right and make it OO and secure? I know that I need incorporate prepared queries- how to do it the best way? Please provide some code

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  • Java program using a class from a JAR file

    - by Myn
    Hi guys, I'll try to phrase this as best I can. I have a program which has an API-like functionality - it uses reflection to dynamically call methods from within a class. In this instance: Server.java public static void main(String[] args) { Class<?> clazz = Class.forName("DiHandler"); StHandler out = (StHandler) clazz; out.read(); DiHandler.java // implements StHandler import edu.ds.*; public void read() { Ds aType = new Ds(); aType = "134"; } So DiHandler has a method read() which can contain anything, it doesn't matter to Server.java after compile time. My problem is: DiHandler.java uses the class Ds from a JAR file. When I'm working on DiHandler.java in Eclipse (in a separate project from the project Server.java is in) I can add this JAR without a problem. But when I move DiHandler.class, after it's compiled, to be used by Server.class, how can it still use the JAR file? I hope this makes some sense, I suppose another way to phrase it would be how can I allow DiHandler to call on a class from the JAR without editing the classpath? Thanks very much in advance and sorry for any confusion or poor phrasing, I can only offer thanks and the customary offer of a pint for any assistance. M

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  • Proper Memory Management for Objective-C Method

    - by Justin
    Hi, I'm programming an iPhone app and I had a question about memory management in one of my methods. I'm still a little new to managing memory manually, so I'm sorry if this question seems elementary. Below is a method designed to allow a number pad to place buttons in a label based on their tag, this way I don't need to make a method for each button. The method works fine, I'm just wondering if I'm responsible for releasing any of the variables I make in the function. The application crashes if I try to release any of the variables, so I'm a little confused about my responsibility regarding memory. Here's the method: FYI the variable firstValue is my label, it's the only variable not declared in the method. -(IBAction)inputNumbersFromButtons:(id)sender { UIButton *placeHolderButton = [[UIButton alloc] init]; placeHolderButton = sender; NSString *placeHolderString = [[NSString alloc] init]; placeHolderString = [placeHolderString stringByAppendingString:firstValue.text]; NSString *addThisNumber = [[NSString alloc] init]; int i = placeHolderButton.tag; addThisNumber = [NSString stringWithFormat:@"%i", i]; NSString *newLabelText = [[NSString alloc] init]; newLabelText = [placeHolderString stringByAppendingString:addThisNumber]; [firstValue setText:newLabelText]; //[placeHolderButton release]; //[placeHolderString release]; //[addThisNumber release]; //[newLabelText release]; } The application works fine with those last four lines commented out, but it seems to me like I should be releasing these variables here. If I'm wrong about that I'd welcome a quick explanation about when it's necessary to release variables declared in functions and when it's not. Thanks.

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  • Dimension Reduction in Categorical Data with missing values

    - by user227290
    I have a regression model in which the dependent variable is continuous but ninety percent of the independent variables are categorical(both ordered and unordered) and around thirty percent of the records have missing values(to make matters worse they are missing randomly without any pattern, that is, more that forty five percent of the data hava at least one missing value). There is no a priori theory to choose the specification of the model so one of the key tasks is dimension reduction before running the regression. While I am aware of several methods for dimension reduction for continuous variables I am not aware of a similar statical literature for categorical data (except, perhaps, as a part of correspondence analysis which is basically a variation of principal component analysis on frequency table). Let me also add that the dataset is of moderate size 500000 observations with 200 variables. I have two questions. Is there a good statistical reference out there for dimension reduction for categorical data along with robust imputation (I think the first issue is imputation and then dimension reduction)? This is linked to implementation of above problem. I have used R extensively earlier and tend to use transcan and impute function heavily for continuous variables and use a variation of tree method to impute categorical values. I have a working knowledge of Python so if something is nice out there for this purpose then I will use it. Any implementation pointers in python or R will be of great help. Thank you.

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  • Issue selenium code maintenance

    - by Rajasankar
    I want to group the common methods in one file and use it. For example, login to a page using selenium may be used in multiple times. Define that in class A and call it in class B. However, it throws null pointer exception. class A has public void test_Login() throws Exception { try{ selenium.setTimeout("60000"); selenium.open("http://localhost"); selenium.windowFocus(); selenium.windowMaximize(); selenium.windowFocus(); selenium.type("userName", "admin"); selenium.type("password", "admin"); Result=selenium.isElementPresent("//input[@type='image']"); selenium.click("//input[@type='image']"); selenium.waitForPageToLoad(Timeout); } catch(Exception ex) { System.out.println(ex); ex.printStackTrace(); } } with all other java syntax in class B public void test_kk() throws Exception { try { a.test_Login(); } catch(Exception ex) { System.out.println(ex); ex.printStackTrace(); } } with all syntax. When I execute class B, I got this error, java.lang.NullPointerException at A.test_Login(A.java:32) at B.test_kk(savefile.java:58) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at junit.framework.TestCase.runTest(TestCase.java:168) at junit.framework.TestCase.runBare(TestCase.java:134) at com.thoughtworks.selenium.SeleneseTestCase.runBare(SeleneseTestCase.j ava:212) at junit.framework.TestResult$1.protect(TestResult.java:110) at junit.framework.TestResult.runProtected(TestResult.java:128) at junit.framework.TestResult.run(TestResult.java:113) at junit.framework.TestCase.run(TestCase.java:124) at junit.framework.TestSuite.runTest(TestSuite.java:232) at junit.framework.TestSuite.run(TestSuite.java:227) at junit.textui.TestRunner.doRun(TestRunner.java:116) at junit.textui.TestRunner.doRun(TestRunner.java:109) at junit.textui.TestRunner.run(TestRunner.java:77) at B.main(B.java:77) I hope someone must have tried this before. I may miss something here.

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  • What would be a better implementation of shared variable among subclass

    - by Churk
    So currently I have a spring unit testing application. And it requires me to get a session cookie from a foreign authentication source. Problem what that is, this authentication process is fairly expensive and time consuming, and I am trying to create a structure where I am authenticate once, by any subclass, and any subsequent subclass is created, it will reuse this session cookie without hitting the authentication process again. My problem right now is, the static cookie is null each time another subclass is created. And I been reading that using static as a global variable is a bad idea, but I couldn't think of another way to do this because of Spring framework setting things during run time and how I would set the cookie so that all other classes can use it. Another piece of information. The variable is being use, but is change able during run time. It is not a single user being signed in and used across the board. But more like a Sub1 would call login, and we have a cookie. Then multiple test will be using that login until SubX will come in and say, I am using different credential, so I need to login as something else. And repeats. Here is a outline of my code: public class Parent implements InitializingBean { protected static String BASE_URL; public static Cookie cookie; ... All default InitializingBean methods ... afterPropertiesSet() { cookie = // login process returns a cookie } } public class Sub1 extends Parent { @resource public String baseURL; @PostConstruct public void init() { // set parents with my baseURL; BASE_URL = baseURL; } public void doSomething() { // Do something with cookie, because it should have been set by parent class } } public class Sub2 extends Parent { @resource public String baseURL; @PostConstruct public void init() { // set parents with my baseURL; BASE_URL = baseURL; } public void doSomethingElse() { // Do something with cookie, because it should have been set by parent class } }

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  • When to save a mongoose model

    - by kentcdodds
    This is an architectural question. I have models like this: var foo = new mongoose.Schema({ name: String, bars: [{type: ObjectId, ref: 'Bar'}] }); var FooModel = mongoose.model('Foo', foo); var bar = new mongoose.Schema({ foobar: String }); var BarModel = mongoose.model('Bar', bar); Then I want to implement a convenience method like this: BarModel.methods.addFoo = function(foo) { foo.bars = foo.bars || []; // Side note, is this something I should check here? foo.bars.push(this.id); // Here's the line I'm wondering about... Should I include the line below? foo.save(); } The biggest con I see about this is that if I did include foo.save() then I should pass in a callback to addFoo so I avoid issues with the async operation. I'm thinking this is not preferable. But I also think it would be nice to include because addFoo hasn't really "addedFoo" until it's been saved... Am I breaking any design best practices doing it either way?

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  • Setting UITabBarItem title from UINavigationController?

    - by fuzzygoat
    I have setup a UITabBarController with two tabs, one is a simple UIViewController and the other is a UINavigationController using second UIViewController as its rootController to set up a UITableView. My question is with regard to naming the tabs (i.e. UITabBarItem) For the first tab (simple UIViewController) I have added the following (see below) to the controllers -init method. - (id)init { self = [super init]; if(self) { UITabBarItem *tabBarItem = [self tabBarItem]; [tabBarItem setTitle:@"ONE"]; } return self; } For the other tab I have added (see below) to the second controllers init (rootController). - (id)init { self = [super init]; if(self) { UITabBarItem *tabBarItem = [[self navigationController] tabBarItem]; [tabBarItem setTitle:@"TWO"]; } return self; } Am I setting the second tabBarItem title in the right place as currently it is not showing? EDIT: I can correctly set the UITabBarItem from within the AppDelegate when I first create the controllers, ready for adding to the UITabBarController. But I really wanted to do this in the individual controller -init methods for neatness. // UITabBarController UITabBarController *tempRoot = [[UITabBarController alloc] init]; [self setRootController:tempRoot]; [tempRoot release]; NSMutableArray *tabBarControllers = [[NSMutableArray alloc] init]; // UIViewController ONE MapController *mapController = [[MapController alloc] init]; [tabBarControllers addObject:mapController]; [mapController release]; // UITableView TWO TableController *rootTableController = [[TableController alloc] init]; UINavigationController *tempNavController = [[UINavigationController alloc] initWithRootViewController:rootTableController]; [rootTableController release]; [tabBarControllers addObject:tempNavController]; [tempNavController release]; [rootController setViewControllers:tabBarControllers]; [tabBarControllers release]; [window addSubview:[rootController view]]; [window makeKeyAndVisible];

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