iPhone dev 20

Found one piece of the puzzle. To add views so that they are visible, the window has a method called "addSubview", seems to be similar to addChild in ActionScript. A default windowed iPhone project already has a "window" attribute in the delegate class. applicationDidFinishLaunching also contains a reference to the XIB file. A view controller has an initWithNibName method that takes the name of a XIB file.

Found an answer to the source code generation question too:

It doesn’t generate source code, instead it allows you to manipulate objects directly and then save those objects in an archive called a nib file. At runtime, when a nib file is loaded the objects are unarchived and restored to the state they were in when you saved the file

iPhone dev 19

So this is how the code knows about objects from Interface Builder. The code has a class called (something)AppDelegate, which has an applicationDidFinishLaunching method that gets called at start. The *AppDelegate class can have IBOutlets for different things like buttons and window from IB, so that it can reference them.

But still, how do I add a new XIB file containing a different view to the project and reference it from code?

iPhone dev 18

I'm back from the sidetrack, at least for now. Game prototypes and MySpace widgets were taking up my time, and probably a bit later will again, but today I'm figuring out iPhone stuff again.

I really still don't understand the relationship between the Interface Builder and code. If I make a view in Interface Builder and add the XIB file to my project and build the project, did it now create a class definition for it automatically? How can I even find out? I feel frustrated that magical things are happening in the background, code is apparently created that I have no awareness of. But this feeling is familiar, I know it will be replaced by understanding if I just continue on this long enough. Things will click into place, and then it will be a breeze to create things. That'll keep me motivated to continue on.

What I want to accomplish is simple. I want a button in the main screen, that when pressed slides out another view which is also constructed in the Interface Builder. But to do this, somehow I need to reference this other view from code, and I don't know how it appears there. I see at least these options of how this might work:

a) Perhaps if I just add a XIB file to a project, Xcode does something magical behind the scenes that results in a class definition being available to all code, which I then have to instantiate. This seems unlikely somehow.

b) Perhaps adding a XIB file to a project causes objects defined in the file to be instantiated. This seems likely, I remember reading that XIB files are kind of frozen object relationships. But when they are thawed, where are they?

c) Adding a XIB file to a project is not enough by itself, but you need to create your own proxy classes in Xcode to be able to reference them. But this wouldn't solve the issue previously mentioned. Even if I know the class names, I still need to reference the thawed objects.

Gimme the thawed objects!

YouTube is easy?

I read a lot of blogs where developers voice their opinions on how to do successful things. Often YouTube is raised as an example of a service that was easy to implement, but filled a real need in a user-friendly way (unlike Google Video) and so became popular. I agree with everything except the "easy" part. If I think about web services, YouTube really doesn't seem comparatively on the easy side.

YouTube seems like a total nightmare to scale for starters. Their bandwidth usage boggles the mind. YouTube currently uses more bandwidth than the entire Internet did less than eight years ago! They spend an estimated million bucks PER DAY on bandwidth.

So OK, perhaps when they say it was easy to implement, they mean when it started, not the way it is right now. Some blogs like to point out that because they use PHP and MySQL, this makes it easy to implement. Granted, the site UI part itself doesn't seem to be especially difficult. But is that really the meaty part of YouTube? Personally I think transcoding is the essential and also the difficult part. Perhaps they use something like FFMPEG to do that, making it easier than I imagine, but they really had to overcome some kind of a mental hurdle to realize that this uploading thing could ever work well enough.

Also from a legal standpoint it does not seem easy. YouTube seems like it might have been much easier to start from China or somewhere with less strict copyright laws. Being a company in the US, I wonder how they got any sleep at night with lawsuits and cease and desists flying at them left and right.

And now they have yet another tiny little detail: how to even make any money from all this. The founders Chad Hurley and Steve Chen of course don't really have to worry too much about this any longer, but I'm thinking about this from the point of view of the business itself. Assuming they really are spending $1M/day on bandwidth, and believing the compete.com estimate that they have 64M monthly uniques, they would need to extract about 50 cents per user per month just to cover the bandwidth cost.

I don't believe they are doomed. It can likely all be made to work, maybe that $1M/day bandwidth will cost a small fraction of that after 10 years. Maybe there is some magical d'uh-obvious moneymaking scheme they will come up with. What I just mean is that none of this makes me feel like YouTube should be the first company people pick as an example of something "easy" to do.

Here's how to monetize Twitter

Add a gifting feature called "bribes", similar to the gifts you can send on Facebook, except they are gifts that all of your followers will get. They are collectible items totally controlled by Twitter, and cost real money to buy. You would buy these items to reward your followers and to encourage more people to follow you.