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  • WinForms Dynamic Label

    - by tolga
    I am creating dynamic labels and letting users change attributes of the labes like backcolor and so by sending unicode. However I don't know how to check if the label exists therefore I can't manipulate the dynamicly created label. below is my code: if ((InputBox.Text.StartsWith("p")) && (InputBox.Text.EndsWith("}")))// only process if the message starts with p and ends with } { string Message = InputBox.Text; InputBox.Text = "";// Clear the box when done. // Butt1 message line if (Message.StartsWith("plabelt1")) { if (Message.StartsWith("plabelt1_BackColor")) { Message = Message.Substring(19); //labelt1.BackColor = System.Drawing.Color.FromName(Message.Replace("}", "")); } } private void ImageBox_DragDrop(object sender, DragEventArgs e) { //Graphics g = ImageBox.CreateGraphics(); //g.DrawImage((Image)e.Data.GetData(DataFormats.Bitmap), //new Point(e.X - this.Left, e.Y - this.Top - 150)); Point p2 = PointToClient(Cursor.Position); Label buttlbl_ = new Label(); labelCount++; buttlbl_.Name = "labelt" + labelCount.ToString(); buttlbl_.Location = new Point(p2.X, p2.Y); buttlbl_.Size = new System.Drawing.Size(37, 37); buttlbl_.BackColor = System.Drawing.Color.DarkGray; this.Controls.Add(buttlbl_); buttlbl_.BringToFront(); ImageBox.Invalidate(); } } Any suggestions?

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  • How to refactor a Python “god class”?

    - by Zearin
    Problem I’m working on a Python project whose main class is a bit “God Object”. There are so friggin’ many attributes and methods! I want to refactor the class. So Far… For the first step, I want to do something relatively simple; but when I tried the most straightforward approach, it broke some tests and existing examples. Basically, the class has a loooong list of attributes—but I can clearly look over them and think, “These 5 attributes are related…These 8 are also related…and then there’s the rest.” getattr I basically just wanted to group the related attributes into a dict-like helper class. I had a feeling __getattr__ would be ideal for the job. So I moved the attributes to a separate class, and, sure enough, __getattr__ worked its magic perfectly well… At first. But then I tried running one of the examples. The example subclass tries to set one of these attributes directly (at the class level). But since the attribute was no longer “physically located” in the parent class, I got an error saying that the attribute did not exist. @property I then read up about the @property decorator. But then I also read that it creates problems for subclasses that want to do self.x = blah when x is a property of the parent class. Desired Have all client code continue to work using self.whatever, even if the parent’s whatever property is not “physically located” in the class (or instance) itself. Group related attributes into dict-like containers. Reduce the extreme noisiness of the code in the main class. For example, I don’t simply want to change this: larry = 2 curly = 'abcd' moe = self.doh() Into this: larry = something_else('larry') curly = something_else('curly') moe = yet_another_thing.moe() …because that’s still noisy. Although that successfully makes a simply attribute into something that can manage the data, the original had 3 variables and the tweaked version still has 3 variables. However, I would be fine with something like this: stooges = Stooges() And if a lookup for self.larry fails, something would check stooges and see if larry is there. (But it must also work if a subclass tries to do larry = 'blah' at the class level.) Summary Want to replace related groups of attributes in a parent class with a single attribute that stores all the data elsewhere Want to work with existing client code that uses (e.g.) larry = 'blah' at the class level Want to continue to allow subclasses to extend, override, and modify these refactored attributes without knowing anything has changed Is this possible? Or am I barking up the wrong tree?

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  • Odd ActiveRecord model dynamic initialization bug in production

    - by qfinder
    I've got an ActiveRecord (2.3.5) model that occasionally exhibits incorrect behavior that appears to be related to a problem in its dynamic initialization. Here's the code: class Widget < ActiveRecord::Base extend ActiveSupport::Memoizable serialize :settings VALID_SETTINGS = %w(show_on_sale show_upcoming show_current show_past) VALID_SETTINGS.each do |setting| class_eval %{ def #{setting}=(val); self.settings[:#{setting}] = (val == "1"); end def #{setting}; self.settings[:#{setting}]; end } end def initialize_settings self.settings ||= { :show_on_sale => true, :show_upcoming => true } end after_initialize :initialize_settings # All the other stuff the model does end The idea was to use a single record field (settings) to persist a bunch of configuration data for this object, but allow all the settings to seamlessly work with form helpers and the like. (Why this approach makes sense here is a little out of scope, but let's assume that it does.) Net-net, Widget should end up with instance methods (eg #show_on_sale= #show_on_sale) for all the entires in the VALID_SETTINGS array. Any default values should be specified in initialize_settings. And indeed this works, mostly. In dev and staging, no problems at all. But in production, the app sometimes ends up in a state where a) any writes to the dynamically generated setters fail and b) none of the default values appear to be set - although my leading theory is that the dynamically generated reader methods are just broken. The code, db, and environment is otherwise identical between the three. A typical error message / backtrace on the fail looks like: IndexError: index 141145 out of string (eval):2:in []=' (eval):2:inshow_on_sale=' [GEM_ROOT]/gems/activerecord-2.3.5/lib/active_record/base.rb:2746:in send' [GEM_ROOT]/gems/activerecord-2.3.5/lib/active_record/base.rb:2746:inattributes=' [GEM_ROOT]/gems/activerecord-2.3.5/lib/active_record/base.rb:2742:in each' [GEM_ROOT]/gems/activerecord-2.3.5/lib/active_record/base.rb:2742:inattributes=' [GEM_ROOT]/gems/activerecord-2.3.5/lib/active_record/base.rb:2634:in `update_attributes!' ...(then controller and all the way down) Ideas or theories as to what might be going on? My leading theory is that something is going wrong in instance initialization wherein the class instance variable settings is ending up as a string rather than a hash. This explains both the above setter failure (:show_on_sale is being used to index into the string) and the fact that getters don't work (an out of bounds [] call on a string just returns nil). But then how and why might settings occasionally end up as a string rather than hash?

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  • Find a dynamic added tag with javascript

    - by Jake
    I am trying to see how to find a tag that was added dynamically within a table as so: ParentTag= document.getElementById('parentdiv'); var newTag = document.createElement('div'); newTag.innerHTML="<span class="ImNew"></span>" ParentTag.appendChild(newTag); How will I be able to find that tag in javascript, not leaning towards using jquery so no live recommendations please.. Trying to find that new tag in strictly javascript.

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  • How to use a separate class to validate credit card numbers in C#

    - by EvanRyan
    I have set up a class to validate credit card numbers. The credit card type and number are selected on a form in a separate class. I'm trying to figure out how to get the credit card type and number that are selected in the other class (frmPayment) in to my credit card class algorithm: public enum CardType { MasterCard, Visa, AmericanExpress } public sealed class CardValidator { public static string SelectedCardType { get; private set; } public static string CardNumber { get; private set; } private CardValidator(string selectedCardType, string cardNumber) { SelectedCardType = selectedCardType; CardNumber = cardNumber; } public static bool Validate(CardType cardType, string cardNumber) { byte[] number = new byte[16]; int length = 0; for (int i = 0; i < cardNumber.Length; i++) { if (char.IsDigit(cardNumber, i)) { if (length == 16) return false; number[length++] = byte.Parse(cardNumber[i]); //not working. find different way to parse } } switch(cardType) { case CardType.MasterCard: if(length != 16) return false; if(number[0] != 5 || number[1] == 0 || number[1] > 5) return false; break; case CardType.Visa: if(length != 16 & length != 13) return false; if(number[0] != 4) return false; break; case CardType.AmericanExpress: if(length != 15) return false; if(number[0] != 3 || (number[1] != 4 & number[1] != 7)) return false; break; } // Use Luhn Algorithm to validate int sum = 0; for(int i = length - 1; i >= 0; i--) { if(i % 2 == length % 2) { int n = number[i] * 2; sum += (n / 10) + (n % 10); } else sum += number[i]; } return (sum % 10 == 0); } }

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  • impress.js Navigation with active class

    - by ArtGoddess
    I would like to use impress.js in order to make a website, with a navigation bar. In each slide, the corresponding anchor or div must have an "active" class, in order to achieve a different link appearance. I have followed all instructions provided here: https://github.com/Ralt/impress.js/commit/f88feb8cae704ce27bd2168bdb77768f516ac2da#L2R605 but the "active" class on the correct menu must be added. This is the code that generates the menu items. How can I add for example the "active" class in the first link? /* ************************ MENU ***************************** */ // Capitalize first letter of string // @see http://stackoverflow.com/a/1026087/851498 var capitalize = function( str ) { return str.charAt(0).toUpperCase() + str.slice(1); } // `showMenu` API function creates the menu // It defines the names of each entry by the id capitalized. var showMenu = function() { // Create the menu wrapper and the element that will be cloned // for each entry. var menu = document.createElement('div'), el = document.createElement('div'); // Apply some classes menu.className = 'menu'; el.className = 'menu-item'; // Create an element that will be the "button" and append it // to the menu var button = document.createElement('div'); button.className = 'menu-button'; button.textContent = 'Menu'; menu.appendChild(button); // Now, for each div in #impress, add an entry to the menu [].forEach.call(byId('impress').firstElementChild.children, function( child, index ) { var newEl = el.cloneNode(), i = index + 1, text = i + '. ' + capitalize(child.id); // Set the text of the new element newEl.textContent = text; // Add an onclick event to the new element // We need to use a closure to make sure the index is correct (function( index ) { newEl.addEventListener('click', function() { goto(index); }); }( index )); // And append the new element to the menu menu.appendChild(newEl); }); // And append the menu to #impress document.body.appendChild(menu); }; Then, in each click it must be removed the active class on the current, and add it to the clicked element. // Remove the active class from the current active document.querySelector( '.active' )[ 0 ].classList.remove( 'active' ); // And add it to the clicked index byId('impress').firstElementChild.children[ index ].classList.add( 'active' ); Where do I have to apply this code? Thank you!

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  • android webview returns blank page when load dynamic html page

    - by user2962555
    I am trying to click one button to load a page into a div block dynamically. To test it, I try to append a list item with text "abc" into the loaded page. However, I always get a blank page. load function works fine because if I try to load a static page, it works. Following is my main html page code. <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>LoadPageTest</title> <link rel="stylesheet" href="http://fonts.googleapis.com/css?family=Open+Sans:300,400,700"> <link rel="stylesheet" href="./css/customizedstyle.css"> <link rel="stylesheet" href="./css/themes/default/jquery.mobile-1.4.3.min.css"> <link rel="stylesheet" href="./css/jqm-demos.css"> <script src="./js/jquery.js"></script> <script scr="./js/customizedjs.js"></script> <script src="./js/jquery.mobile-1.4.3.min.js"></script> <script> $( document ).on( "pagecreate", "#demo-page", function() { $( document ).on( "swipeleft swiperight", "#demo-page", function( e ) { if ( $( ".ui-page-active" ).jqmData( "panel" ) !== "open" ) { if ( e.type === "swipeleft" ) { $( "#right-panel" ).panel( "open" ); } } }); }); </script> <style type="text/css"> body { overflow:hidden; } </style> </head> <body style= "overflow:hidden" scrolling="no"> <style type="text/css"> body { overflow:hidden; } </style> <div data-role="page" id="main-page" style= "overflow:hidden" scrolling="no"> <div role="main" class="ui-content" id ="maindiv" style= "overflow: auto"> Will load diff pages here. </div><!-- /content --> <div data-role="panel" id="left-panel" data-theme="b"> <ul data-role="listview" data-icon="false" id="menu"> <li> <a href="#" id = "btnA" data-rel="close">Go Page A <img src="./images/icona.png" class="ui-li-thumb"/> </li> <li> <a href="#" id = "btnB" data-rel="close">Go Page B <img src="./images/iconb.png" class="ui-li-thumb"/> </li> </ul> </div><!-- /panel --> <script type="text/javascript"> $("#btnA").on("click", function(){ $("#maindiv").empty(); $("#maindiv").load("pageA.html"); }); $("#btnB").on("click", function(){ $("#maindiv").empty(); $("#maindiv").load("pageB.html"); }); </script> </div><!-- /page --> </body> </html> Next is code for the page I try to load dynamically. <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>Page should be loaded</title> <link rel="stylesheet" href="http://fonts.googleapis.com/css?family=Open+Sans:300,400,700"> <link rel="stylesheet" href="./css/customizedstyle.css"> <link rel="stylesheet" href="./css/themes/default/jquery.mobile-1.4.3.min.css"> <link rel="stylesheet" href="./css/jqm-demos.css"> <script src="./js/jquery.js"></script> <script scr="./js/customizedjs.js"></script> <script src="./js/jquery.mobile-1.4.3.min.js"></script> <script> $(document).on('pagebeforeshow', function () { $('#postlist').append('<li> abc </li>'); $('#postlist').listview('refresh'); }); </script> </head> <body > <div data-role="page" id="posthome"> <div data-role = "content"> <ul data-role='listview' id = "postlist"> </ul> </div> </div> </body> </html> I doubt if it is because my javascript in the page doesn't work, cause the swipe js code in the main page seems not work either. Is that possible? I have enabled javascript in the onCreate() function of the activity file as below. protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_message); new LongRunningGetIO().execute(); mWebView = (WebView) findViewById(R.id.webview); mWebView.setWebViewClient(new AppClient()); mWebView.setVerticalScrollBarEnabled(false); mWebView.getSettings().setJavaScriptEnabled(true); mWebView.getSettings().setDomStorageEnabled(true); mWebView.loadUrl("file:///android_asset/index.html"); } I noticed there is a warning for statement to enable javascript "Using setJavaScriptEnabled can introduce XSS vulnerabilities into you application, review carefully". Will that maybe the reason? Then, I added @SuppressLint("SetJavaScriptEnabled") on top of the activity. The warning is gone, but the js code in pages seem still not work.

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  • How do I copy/clone a dynamic disk in Windows 7?

    - by PP
    I have some dynamic disks (or "partitions" but they are not really partitions) that I want to copy onto spare hard drives. I tried using gpartd (and fdisk for that matter) from a linux live disc. All it saw was hard drives with only one partition encasing the whole hard drive. So gpartd/fdisk is incapable of identifying the dynamic "partitions" and allowing me to copy them. Any tools that can be used to clone/copy a dynamic "partition"? (I'm open to commercial software suggestions if they can do the job).

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  • Use Dynamic DNS to access Java servlet, still need port forward ?

    - by Frank
    If I use Dynamic DNS such as the free service at https://www.dyndns.com, do I still need to set up static IP and do port forward ? I have a DSL, most likely with dynamic IP address, and I run a Java servlet to get Paypal IPN messages on my notebook, in order for the messages to reach my notebook, I : [1] set up static IP and [2] did port forwarding. But I found each time the PC re-starts, it has a different external IP, so I was suggested to [3] get Dynamic DNS service like the free one mentioned above, but now I'm a bit confused, if I have step [3], do I still need to do [1] and [2], isn't step [3] supposed to do [1] and [2] for me ? But since I've already done [1],[2], now I wonder if they would cause trouble for step [3], do I need to undo them ? Or do I need all of them together ?

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  • How to check the version of the dynamic linker?

    - by netvope
    If I run a binary compiled on a newer Linux distro on an older Linux distro, I may get an error like this: a.out: error while loading shared libraries: requires glibc 2.5 or later dynamic linker How can I check the version of the dynamic linker in a Linux system? Is it provided by a package? If so, what's the name of the package? And a theoretical question: Is it possible to update the dynamic linker? (I don't think I'm going to do this but I just want to know.)

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  • Access a windows dynamic hard drive through a virtual machine on ubuntu?

    - by Enigma
    I have a Windows 7 OS and am thinking about transitioning to a dual boot set up with Ubuntu 12.04. From what I recall, it is not possible to natively access Dynamic Windows Partitions in a Linux OS. My thought is that it might be possible to have a virtual machine (running windows) installed within Ubuntu access the physical dynamic drive. The problem comes to whether VMWare can access the physical disk "high enough" to be able to mount it within the windows virtual machine as a native device or if it gets passed through from the native Linux OS. This is really the only thing holding me back from switching to a dual-boot set up as the dynamic disk is made up of 4 or 5 hard drives and I would very much like access to the data on both OS's. Alternatively, is there another solution for combining multiple physical hard drives into one virtual hard drive that would be readable on both OS's?

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  • C# - Get values of static properties from static class

    - by JamesW
    I'm trying to loop through some static properties in a simple static class in order to populate a combo box with their values, but am having difficulties. Here is the simple class: public static MyStaticClass() { public static string property1 = "NumberOne"; public static string property2 = "NumberTwo"; public static string property3 = "NumberThree"; } ... and the code attempting to retrieve the values: Type myType = typeof(MyStaticClass); PropertyInfo[] properties = myType.GetProperties( BindingFlags.Public | BindingFlags.Static | BindingFlags.DeclaredOnly); foreach (PropertyInfo property in properties) { MyComboBox.Items.Add(property.GetValue(myType, null).ToString()); } If I don't supply any binding flags then I get about 57 properties including things like System.Reflection.Module Module and all sorts of other inherited things I don't care about. My 3 declared properties are not present. If I supply various combinations of other flags then it always returns 0 properties. Great. Does it matter that my static class is actually declared within another non-static class? Please help! What am I doing wrong?

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  • g++ C++0x enum class Compiler Warnings

    - by Travis G
    I've been refactoring my horrible mess of C++ type-safe psuedo-enums to the new C++0x type-safe enums because they're way more readable. Anyway, I use them in exported classes, so I explicitly mark them to be exported: enum class __attribute__((visibility("default"))) MyEnum : unsigned int { One = 1, Two = 2 }; Compiling this with g++ yields the following warning: type attributes ignored after type is already defined This seems very strange, since, as far as I know, that warning is meant to prevent actual mistakes like: class __attribute__((visibility("default"))) MyClass { }; class __attribute__((visibility("hidden"))) MyClass; Of course, I'm clearly not doing that, since I have only marked the visibility attributes at the definition of the enum class and I'm not re-defining or declaring it anywhere else (I can duplicate this error with a single file). Ultimately, I can't make this bit of code actually cause a problem, save for the fact that, if I change a value and re-compile the consumer without re-compiling the shared library, the consumer passes the new values and the shared library has no idea what to do with them (although I wouldn't expect that to work in the first place). Am I being way too pedantic? Can this be safely ignored? I suspect so, but at the same time, having this error prevents me from compiling with Werror, which makes me uncomfortable. I would really like to see this problem go away.

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  • class array variable initialization error in java

    - by trinity
    Hello I am trying to write a java program that reads an input file consisting of URLs , extracts tokens from these , and accordingly insert into : class Tokens { String name ; int count ; } , where name is the name of every unique token , and count is the frequency of that token in the URLs file..I've written the following code : import java.io.*; import java.net.*; public class Main { static class Tokens { String name; int count; } public static void main(String[] args) { String url_str,host; String htokens[]; URL url; boolean found=false; Tokens t[]; int i,j,k; try { File f=new File("urlfile.txt"); FileReader fr=new FileReader(f); BufferedReader br=new BufferedReader(fr); while((url_str=br.readLine())!=null) { url=new URL(url_str); host=url.getHost(); htokens=host.split("\\.|\\-|\\_|\\~|[0-9]"); for(i=0;i<htokens.length;i++) { if(!htokens[i].isEmpty()) { for(j=0;j<t.length;j++) { if(htokens[i].equals(t[j].name)) { t[j].count++; found=true; } } if(!found) { k=t.length; t[k].name=htokens[i]; t[k].count=1; } } } System.out.println(t.length + "class tokens :"); for(i=0;i<t.length;i++) { System.out.println("name :"+t[i].name+" frequency :"+t[i].count); } } br.close(); fr.close(); } catch(Exception e) { System.out.println(e); } } } But when i run it , it says : variable t not initialized.. What should i do to set it right ?

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  • Extension methods in class library project

    - by Mostafa
    I've implemented some extension methods and put those in separate Class Library project. Imagine I have a simple extension method like this in class library called MD.Utility: namespace MD.Utility { public static class ExtenMethods { public static bool IsValidEmailAddress(this string s) { Regex regex = new Regex(@"^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$"); return regex.IsMatch(s); } } } But nowhere in WebApp like App_code folder or WebFroms code-behind page I can't use this Extension method. If I do like this: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using MD.Utility; public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { string email = "[email protected]"; if (email.IsValidEmailAddress()) { //To do } } } The compiler doesn't recognize IsValidEmailAddress() and even no intellisense support. While if I put my extension method in App_Code folder it's ok for using in another cs file in App_code Folder or Web Form code-behind pages.

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  • flash as3 document class and event listeners

    - by Lee
    I think i have this document class concept entirly wrong now, i was wondering if someone mind explaining it.. I assumed that the above class would be instantiated within the first frame on scene one of a movie. I also assumed that when changing scenes the state of the class would remain constant so any event listeners would still be running.. Scene 1: I have a movieclip named ui_mc, that has a button in for muting sound. Scene 2: I have the same movie clip with the same button. Now the eventListener picks it up in the first scene, however it does not in the second. I am wondering for every scene do the event listeners need to be resetup? If that is the case if their an event listener to listen for the change in scene, so i can set them back up again lol.. Thanks in advance.. package { import flash.display.MovieClip; import flash.events.MouseEvent; import flash.media.Sound; import flash.media.SoundChannel; public class game extends MovieClip { public var snd_state:Boolean = true; public function game() { ui_setup(); } public function ui_setup():void { ui_mc.toggleMute_mc.addEventListener(MouseEvent.CLICK, snd_toggle); } private function snd_toggle(event:MouseEvent):void { // 0 = No Sound, 1 = Full Sound trace("Toggle"); } } }

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  • Help with my PHP template class

    - by blerh
    I want to separate the output of HTML from my program code in my projects, so I wrote a very simple database class. <?php class Template { private $template; function load($filePath) { if(!$this->template = file_get_contents($filePath)) $this->error('Error: Failed to open <strong>' . $filePath . '</strong>'); } function replace($var, $content) { $this->template = str_replace("{$var}", $content, $this->template); } function display() { echo $this->template; } function error($errorMessage) { die('die() by template class: <strong>' . $errorMessage . '</strong>'); } } ?> The thing I need help with is the display() method. Say for example I use this code: $tplObj = new Template(); $tplObj->load('index.php'); $tplObj->replace('{TITLE}', 'Homepage'); $tplObj->display(); And the index.php file is this: <html> <head> <title>{TITLE}</title> </head> <body> <h1>{TITLE}</h1> <?php if($something) { echo '$something is true'; } else { echo '$something is false'; } ?> </body> </html> I'm just wondering if the PHP code in there would be run? Or would it just be sent to the browser as plaintext? I was using eval() in my template class but I hate that function :P Thanks.

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  • UIActivityIndicatorView in a class without a view

    - by Structurer
    Hi I have defined a class that does a lengthy task and I call it from several other classes. Now I want to show an Activity Indicator while this task is doing it's thing, and then remove it once it's done. Since this is just a boring background task, this class doesn't have a view, and I guess that is where I run into my problem. I can't get this thing to show. This is what I have done in my class: UIActivityIndicatorView *activityIndicator = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 32.0f, 32.0f)]; [activityIndicator setCenter:CGPointMake(160.0f, 208.0f)]; activityIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhite; UIView *contentView = [[UIView alloc]initWithFrame:[[UIScreen mainScreen] applicationFrame]]; [contentView addSubview:activityIndicator]; [activityIndicator startAnimating]; // Do the class lengthy task that takes several seconds..... [contentView release]; [activityIndicator release]; I guess I do something wrong when I get the contentView, but how should I get it properly? Thanks for any advices...

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  • Design of std::ifstream class

    - by Nawaz
    Those of us who have seen the beauty of STL try to use it as much as possible, and also encourage others to use it wherever we see them using raw pointers and arrays. Scott Meyers have written a whole book on STL, with title Effective STL. Yet what happened to the developers of ifstream that they preferred char* over std::string. I wonder why the first parameter of ifstream::open() is of type const char*, instead of const std::string &. Please have a look at it's signature: void open(const char * filename, ios_base::openmode mode = ios_base::in ); Why this? Why not this: void open(const string & filename, ios_base::openmode mode = ios_base::in ); Is this a serious mistake with the design? Or this design is deliberate? What could be the reason? I don't see any reason why they have preferred char* over std::string. Note we could still pass char* to the latter function that takes std::string. That's not a problem! By the way, I'm aware that ifstream is a typedef, so no comment on my title.:P. It looks short that is why I used it. The actual class template is : template<class _Elem,class _Traits> class basic_ifstream;

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  • Class Assignment Operators

    - by Maxpm
    I made the following operator overloading test: #include <iostream> #include <string> using namespace std; class TestClass { string ClassName; public: TestClass(string Name) { ClassName = Name; cout << ClassName << " constructed." << endl; } ~TestClass() { cout << ClassName << " destructed." << endl; } void operator=(TestClass Other) { cout << ClassName << " in operator=" << endl; cout << "The address of the other class is " << &Other << "." << endl; } }; int main() { TestClass FirstInstance("FirstInstance"); TestClass SecondInstance("SecondInstance"); FirstInstance = SecondInstance; SecondInstance = FirstInstance; return 0; } The assignment operator behaves as-expected, outputting the address of the other class. Now, how would I actually assign something from the other class? For example, something like this: void operator=(TestClass Other) { ClassName = Other.ClassName; }

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  • Best practice accessing an array set within a class

    - by user350599
    I have created a basic class for a customer. I haven't done this before and want to know the best way to access the data. Should I have a get() method for every field in the customer array or should I simply pass the customer array back and access with the page. i.e. Just return the array class Customer { protected $id; protected $customer; public function __construct($customer_id) { $this->id = $customer_id; $this->set_customer(); } protected function set_customer() { $query = mysql_query("SELECT * FROM customer WHERE id = '$this->id'"); $this->customer = mysql_fetch_row($query); } public function get_customer() { return $this->customer; } } versus create a method for each item in the array class Customer { protected $id; protected $customer; public function __construct($customer_id) { $this->id = $customer_id; $this->set_customer(); } protected function set_customer() { $query = mysql_query("SELECT * FROM customer WHERE id = '$this->id'"); $this->customer = mysql_fetch_row($query); } public function get_customer_name() { return $this->customer->customer_name; } ... ... } versus option 3 based on Tobias' feedback: (not sure if syntax is correct) class Customer { protected $id; protected $customer; public function __construct($customer_id) { $this->id = $customer_id; return $this->set_customer(); } protected function set_customer() { $query = mysql_query("SELECT * FROM customer WHERE id = '$this->id'"); return mysql_fetch_row($query); } }

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  • Execute a function to affect different template class instances

    - by Samer Afach
    I have a complicated problem, and I need help. I have a base case, class ParamBase { string paramValue; //... } and a bunch of class templates with different template parameters. template <typename T> class Param : public ParamBase { T value; //... } Now, each instance of Param has different template parameter, double, int, string... etc. To make it easier, I have a vector to their base class pointers that contains all the instances that have been created: vector<ParamBase*> allParamsObjects; The question is: How can I run a single function (global or member or anything, your choice), that converts all of those different instances' strings paramValue with different templates arguments and save the conversion result to the appropriate type in Param::value. This has to be run over all objects that are saved in the vector allParamsObjects. So if the template argument of the first Param is double, paramValue has to be converted to double and saved in value; and if the second Param's argument is int, then the paramValue of the second has to be converted to int and saved in value... etc. I feel it's almost impossible... Any help would be highly appreciated :-)

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  • Calling Base Class Functions with Inherited Type

    - by Kein Mitleid
    I can't describe exactly what I want to say but I want to use base class functions with an inherited type. Like I want to declare "Coord3D operator + (Coord3D);" in one class, but if I use it with Vector3D operands, I want it to return Vector3D type instead of Coord3D. With this line of code below, I add two Vector3D's and get a Coord3D in return, as told to me by the typeid().name() function. How do I reorganize my classes so that I get a Vector3D on return? #include <iostream> #include <typeinfo> using namespace std; class Coord3D { public: float x, y, z; Coord3D (float = 0.0f, float = 0.0f, float = 0.0f); Coord3D operator + (Coord3D &); }; Coord3D::Coord3D (float a, float b, float c) { x = a; y = b; z = c; } Coord3D Coord3D::operator+ (Coord3D &param) { Coord3D temp; temp.x = x + param.x; temp.y = y + param.y; temp.z = z + param.z; return temp; } class Vector3D: public Coord3D { public: Vector3D (float a = 0.0f, float b = 0.0f, float c = 0.0f) : Coord3D (a, b, c) {}; }; int main () { Vector3D a (3, 4, 5); Vector3D b (6, 7, 8); cout << typeid(a + b).name(); return 0; }

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  • class modifier issues in C# with "private" classes

    - by devoured elysium
    I had a class that had lots of methods: public class MyClass { public bool checkConditions() { return checkCondition1() && checkCondition2() && checkCondition3(); } ...conditions methods public void DoProcess() { FirstPartOfProcess(); SecondPartOfProcess(); ThirdPartOfProcess(); } ...process methods } I identified two "vital" work areas, and decided to extract those methods to classes of its own: public class MyClass { private readonly MyClassConditions _conditions = new ...; private readonly MyClassProcessExecution = new ...; public bool checkConditions() { return _conditions.checkConditions(); } public void DoProcess() { _process.DoProcess(); } } In Java, I'd define MyClassConditions and MyClassProcessExecution as package protected, but I can't do that in C#. How would you go about doing this in C#? Setting both classes as inner classes of MyClass? I have 2 options: I either define them inside MyClass, having everything in the same file, which looks confusing and ugly, or I can define MyClass as a partial class, having one file for MyClass, other for MyClassConditions and other for MyClassProcessExecution. Defining them as internal? I don't really like that much of the internal modifier, as I don't find these classes add any value at all for the rest of my program/assembly, and I'd like to hide them if possible. It's not like they're gonna be useful/reusable in any other part of the program. Keep them as public? I can't see why, but I've let this option here. Any other? Name it! Thanks

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  • Declaring an enum within a class

    - by bporter
    In the following code snippet, the Color enum is declared within the Car class in order to limit the scope of the enum and to try not to "pollute" the global namespace. class Car { public: enum Color { RED, BLUE, WHITE }; void SetColor( Car::Color color ) { _color = color; } Car::Color GetColor() const { return _color; } private: Car::Color _color; }; (1) Is this a good way to limit the scope of the Color enum? Or, should I declare it outside of the Car class, but possibly within its own namespace or struct? I just came across this article today, which advocates the latter and discusses some nice points about enums: http://gamesfromwithin.com/stupid-c-tricks-2-better-enums. (2) In this example, when working within the class, is it best to code the enum as Car::Color, or would just Color suffice? (I assume the former is better, just in case there is another Color enum declared in the global namespace. That way, at least, we are explicit about the enum to we are referring.) Thanks in advance for any input on this.

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