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  • I'm new to OOP/PHP. What's the practicality of visibility and extensibility in classes?

    - by marcdev
    I'm obviously brand new to these concepts. I just don't understand why you would limit access to properties or methods. It seems that you would just write the code according to intended results. Why would you create a private method instead of simply not calling that method? Is it for iterative object creation (if I'm stating that correctly), a multiple developer situation (don't mess up other people's work), or just so you don't mess up your own work accidentally?

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  • Problem using a method in Ruby

    - by Rafal
    I'm very new to Ruby (and OOP as well) and I don't know why the following thing doesn't work in Ruby I extended the String class with a new method. Easy enough. Now I want to extend the Fixnum class. A String object appears somewhere in the class, but I can't use the method that I defined earlier. Why? Is this normal?

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  • Android Load Camera image as Bitmap

    - by GuyNoir
    I am using BitmapFactory.decodeFile to load Bitmaps of images into my application. However, the function returns null on large images (such as those from the camera). The filepath is definitely correct, I just can't figure out why it would return null. I tried supersampling, but it didn't seem to help. Does anyone have any idea why it would do this or how I could more easily load images taken from the camera into a Bitmap? Thanks.

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  • How does the OpenGL ES template work for the iPhone?

    - by thyrgle
    So, I've been trying to figure out why the square is moving up and down the iPhone simulator when Build and Go the template that Apple provides for OpenGL ES. I don't understand why for example they have ES1Render.m, and ES2Render.m instead of just one ESRender.m. Also, where is the equivalent of the glutDisplayFunc, and glutTimerFunc? Thanks in advance.

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  • [validate plugin] custom rule error

    - by vitto
    hi i have added a rule to my form but i can't understand why it does not work!! http://www.pipelabitta.it/form/ This is an example page: the rules is that the check box must be checked and there must be a valid date. From firefox console i can see it returns true or false as i need but the validation does not get triggered. Why is that? Thanks Vitto

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  • iPhone memory management

    - by Prazi
    I am newbie to iPhone programming. I am not using Interface Builder in my programming. I have some doubt about memory management, @property topics in iPhone. Consider the following code @interface LoadFlag : UIViewController { UIImage *flag; UIImageView *preview; } @property (nonatomic, retain) UIImageView *preview; @property (nonatomic, retain) UIImage *flag; @implementation @synthesize preview; @synthesize flag; - (void)viewDidLoad { flag = [UIImage imageNamed:@"myImage.png"]]; NSLog(@"Preview: %d\n",[preview retainCount]); //Count: 0 but shouldn't it be 1 as I am retaining it in @property in interface file preview=[[UIImageView alloc]init]; NSLog(@"Count: %d\n",[preview retainCount]); //Count: 1 preview.frame=CGRectMake(0.0f, 0.0f, 100.0f, 100.0f); preview.image = flag; [self.view addSubview:preview]; NSLog(@"Count: %d\n",[preview retainCount]); //Count: 2 [preview release]; NSLog(@"Count: %d\n",[preview retainCount]); //Count: 1 } When & Why(what is the need) do I have to set @property with retain (in above case for UIImage & UIImageView) ? I saw this statement in many sample programs but didn't understood the need of it. When I declare @property (nonatomic, retain) UIImageView *preview; statement the retain Count is 0. Why doesn't it increase by 1 inspite of retaining it in @property. Also when I declare [self.view addSubview:preview]; then retain Count increments by 1 again. In this case does the "Autorelease pool" releases for us later or we have to take care of releasing it. I am not sure but I think that the Autorelease should handle it as we didn't explicitly retained it so why should we worry of releasing it. Now, after the [preview release]; statement my count is 1. Now I don't need UIImageView anymore in my program so when and where should I release it so that the count becomes 0 and the memory gets deallocated. Again, I am not sure but I think that the Autorelease should handle it as we didn't explicitly retained it so why should we worry of releasing it. What will happen if I release it in -(void) dealloc method In the statement - flag = [UIImage imageNamed:@"myImage.png"]]; I haven't allocated any memory to flag but how can I still use it in my program. In this case if I do not allocate memory then who allocates & deallocates memory to it or is the "flag" just a reference pointing to - [UIImage imageNamed:@"myImage.png"]];. If it is a reference only then do i need to release it. Thanks in advance.

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  • Understanding max JVM heap size

    - by Marcus
    I've read the max heap size on 32bit Windows is ~1.5GB which is due to the fact that the JVM requires contiguous memory. Can someone explain the concept of "contiguous memory" and why you only have max 1.5GB on Windows? Secondly, what then is the max heap size on 64 bit Windows and why is this different than what's available on 32 bit?

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  • Double postback problem

    - by Juan Manuel Formoso
    Hi, I have a ASP.NET 1.1 application, and I'm trying to find out why when I change a ComboBox which value is used to fill another one (parent-child relation), two postbacks are produced. I have checked and checked the code, and I can't find the cause. Here are both call stacks which end in a page_load First postback (generated by teh ComboBox's autopostback) Second postback (this is what I want to find why it's happening) Any suggestion? What can I check?

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  • What is so bad about Singletons

    - by Ewan Makepeace
    The Singleton pattern is a fully paid up member of the GoF Patterns Book but lately seems rather orphaned by the developer world. I still use quite a lot of singletons, especially for Factory classes, and while you have to be a bit careful about multithreading issues (like any class actually) fail to see why they are so awful. This site especially seems to assume that everyone agrees that Singletons are evil. Why?

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  • Bizarre Escape Character Question

    - by William Calleja
    I have the following c# code embedded in a literal <% %> of a c# asp.net page string commandString = "SELECT tblData.Content " + "FROM tblData " + "WHERE (tblData.ref = N\'%"+myCurrentREF+"%\')"; This is breaking my code since it apparently cannot use the \' escape character. Why is it so? other escape characters like \" are working so why isn't \' working?

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  • Learning... anything really

    - by WebDevHobo
    I'm particularly interested in Windows PowerShell, but here's a somewhat more general complaint: When asking for help on learning something new, be it a small subject on PHP or understanding a class in Java, what usually happens is that people direct me towards the documentation pages. What I'm looking for is somewhat of a course. A deep explanation of why something works the way it does. I know my basic programming, like Java and C#. I've never seen C or C++, though I have seen a bit of assembler. I know what the Stack and Heap are, how boxing and unboxing works, why you have to deep-copy an array instead of copying the pointer and some other things. Windows PowerShell on the other hand, I know nothing about. And I notice that when reading the small document or some code, I usually forget what it does or why it works. What I am looking for is preferably, a nice tutorial that explains the beginnings, the concepts, and goes to more difficult things at a steady pace. The only thing documentation can do is explain what a function does. That's no good to me since I don't know what I want to do yet. I could read about a thousand functions, and forget about most of them, because I don't need to implement them right after it. Randomly wandering through the documentation doesn't do me any good. So conclude, what is a good tutorial on Windows Powershell? One which explains in clear language what is happening, one which builds on previous things learned. I don't think googling this is a good idea. Doing a Google search on this would turn up numerous tutorials. And experience tells me that you have to look long and hard to find the gem you're looking for. That's why I'm asking here. Because this is the place where you can find more experienced people. Many of the PowerShell guys among you will know the good ones already, and by asking you, I avoid wasting time that could be spent learning. So to summarize: I will not google this!

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  • Defining golang struct function using pointer or not

    - by Jacob
    Can someone explain to me why appending to an array works when you do this: func (s *Sample) Append(name string) { d := &Stuff{ name: name, } s.data = append(s.data, d) } Full code here But not when you do this: func (s Sample) Append(name string) { d := &Stuff{ name: name, } s.data = append(s.data, d) } Is there any reason at all why you would want to use the second example.

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  • When not to do maximum compression in png?

    - by user1444680
    Intro When saving png images through GIMP, I've always used level 9 (maximum) compression, as I knew that it's lossless. Now I've to specify compression level when saving png format image through GD extension of PHP. Question Is there any case when I shouldn't compress PNG to maximum level? Like any compatibility issues? If there's no problem then why to ask user; why not automatically compress to max?

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  • Java Beginner question about String[] args in the main method

    - by happysoul
    So I just tried excluding String[] args from the main method It compiled alright ! But JVM is showing an exception Why did it compile when String[] args HAS to be included every time ? What is going on here ? Why won't it show a compilation error ? typing this made me think that may be compiler did not see it as THE main method ..is that so ?

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  • Committing Transaction

    - by Costa
    Hi http://msdn.microsoft.com/en-us/library/ms189797.aspx In this link they are committing a transaction within catch clause IF (XACT_STATE()) = 1, I don't get it, if there is an error why they are committing it? even if the problem in select statement and there is no big deal committing it, why don't just roll it back. Thanks

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  • improve javascript prototypal inheritance

    - by Julio
    I'm using a classical javascript prototypal inheritance, like this: function Foo() {} Naknek.prototype = { //Do something }; var Foo = window.Foo = new Foo(); I want to know how I can improve this and why I can't use this model: var Foo = window.Foo = new function() { }; Foo.prototype = { //Do something }; Why this code doesn't work? In my head this is more logical than the classical prototypal inheritance.

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  • Tab Bar and Nav Controller: Where did I go wrong in my Interface Builder wiring?

    - by editor
    Even if you don't know how I've shot myself in the foot, a story which I've tried to lay out below, if you think I've done a good job showing the parameters of my problem I'd appreciate an upvote so that I might be able to grab some attention for my question. I've been working on an iPhone application in XCode and Interface Builder of the Tab Bar project type. After getting a table view of topics (business sectors) working fine I realized that I would need to add a Navigation Control to allow the user to drill into a subtopics (subsectors) table. As a green Objective-C developer, that was confusing, but I managed to get it working by reading various documentation trying out a few different IB options. My current setup is a Tab Bar Controller with Tab 1 as a Navigation Controller and Tab 2 a plain view with a Table View placed into it. The wiring works: I can log when table rows are selected and I'm ready to push a new View Controller onto the stack so that I can display the subtopics Table View. My problem: For some reason the first tab's Table View is a delegate and dataSource of the second ta. It doesn't make sense to me and I can't figure out why that's the only setup that works. Here is the wiring: Navigation Controller (Sectors) is a delegate of Tab Bar Navigation Bar is a delegate of Navigation Controller (Sectors) View Contoller (Sectors) has a view of Table View Table View (in Navigation Controller (Sectors)) is a delegate of First View Controller (Companies) Table View (in Navigation Controller (Sectors)) is a dataSource outlet of First View Controller (Companies) First View Controller (Companies) First View Contoller (Sectors) has a view of Table View Table View (in First View Controller (Companies)) is not hooked up to a dataSource outlet and is not a delegate When I click the tab buttons and look at the Inspector I see that the first tab is correctly hooked up to my MainWindow.xib and the second tab has selected a nib called SecondView.xib. It's in the File's Owner of MainWindow.xib where I inherit UITableViewDataSource and UITableViewDelegate (and also UITabBarControllerDelegate) in the .h, and in the .m where I implement the delegate methods. Why does this setup only work when the Table View in my first tab (View Controller (Sectors)) is a delegate and dataSource of the second tab? I'm confused: why wouldn't it need to be hooked up to the Navigation Controller-enabled tab in which the Table View is seen (Navigation Controller (Sectors))? The Table View seen on the second tab has neither dataSource and is not a delegate. I'm having trouble getting a pushViewController to fire (self.navigationController is not nil but the new View Controller still doesn't load) and I suspect that I need to work out this IB wiring issue before I can troubleshoot why the Nav Controller won't push a new View Controller onto the stack. if(nil == self.navigationController) { NSLog(@"self.navigationController is nil."); } else { NSLog(@"self.navigationController is not nil."); SectorList *subsectorViewController = [[SectorList alloc] initWithNibName:@"SectorList" bundle:nil]; subsectorViewController.title = @"Subsectors"; [[self navigationController] pushViewController:subsectorViewController animated:YES]; [subsectorViewController release]; }

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  • Question about multiple 'catch'

    - by chun
    Can anyone tell me why the output of this class is 'xa'? why the other exception won't be caught? public class Tree { public static void main(String... args){ try { throw new NullPointerException(new Exception().toString()); } catch (NullPointerException e) { System.out.print("x"); } catch (RuntimeException e) { System.out.print("y"); } catch (Exception e) { System.out.print("z"); } finally{System.out.println("a");} } }

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