Errata for iPhone SDK Development

#38742: I just spent half my day messing around with scroll views before finding a video that happened to mention the property I needed to set (contentSize) to actually get it to scroll. This property isn't exposed in IB (at least in the version that ships with the first release of the 3.0 SDK), so you have to set it programatically. I couldn't find any mention of UIScrollView in the book, and it would have saved me a lot of time.--Mike Rentas

#39158: One of the things that is the hardest for me to understand in the example applications, is how all of the objects fit together; what does the whole architecture look like, and why. Who creates this controller? Why is this one in the NIB, and this one outside it? Why is the title for this controller set here, and for that one there? And so on.

Often after reading a chapter I take a sheet of paper and draw a diagram of all the objects, grouped in NIBs and connected with arrows - this helps me understand how it all works on the higher level. I'm thinking it would be good if the book included such high-level analysis sometimes, possibly with some small diagrams (I'm not talking about 5 pages of UML, just a few boxes and arrows). After reading a few chapters, I may know very well how to create a NIB or controller and how to connect stuff, but I don't always understand WHY I am supposed to do this. How do I start, how do I plan how the application is built, what it will consist of... it's not easy to figure this out by yourself.--Jakub Suder

#38815: in the .mobi version of this file (approximately location 620 on a Kindle), the 2nd graphic on PDF page 52 is 90% blank, with the real graphic taking up only a fraction of the page. Even zooming it results in a graphic that is too small to read.--Avram Dorfman

#38862: Similar to the other comments, I would say that it is unclear how you expect the reader to get to the point where the instructions on p. 95 make sense. You seem to imply that he should download the code for RootViewController, but if he does that, then it already contains the code you are about to tell him to insert. If you expect him to build it up himself, then it's not enough to just refer him back to the previous chapter. Making him figure out how to accomplish the prep tasks is ok, but making him figure out what those tasks are by simply referring to Chapter 4 is asking too much.--Avram Dorfman

#39099: It's not clear if you actually want the reader to implement either of these file reading techniques or are just offering then for discussion. It's also confusing to suggest that you could deal with a binary file simply with the other one-line call provided when it returns a data type that is not compatible with the property of the object we are using to display the file.--Avram Dorfman

#39102: I just spent 6 hours debugging my attempt to use the stringWithContentsOfFile: method. It was coming up with empty file contents. After learning how to use NSError, NSDictionary, and enumerators, I was fed the error key "NSFilePath" by the OS, with a value of my file path, which was a valid file. By more-ing the file in Terminal, I realized it has some non-ASCII characters in it. It would be nice if you mentioned that this call will actually return nothing when given a binary file, and that the only non-binary file available to be viewed is PkgInfo.--Avram Dorfman

#39115: The text refers to the figure as a guide for creating the view for the contents controller. I'm assuming we are supposed to use the View XIB template for this. The corresponding empty view we get does not account for the space that the navigation bar takes up. If we fill the view with the text field, even leaving the space indicated by the guides, we end up with a scrolling text field who's bottom we cannot see; if you view a file that does not fit on the screen, and scroll down to see the end of the file, you can pull the last line into view, but it "spring" back out of view when you let go. We can of course just leave some extra blank space below the text field, but I would think there is a more formal way to build a view that needs to account for the space that a nav bar is going to take up.--Avram Dorfman

#39103: Your view design for the file contents includes a field for the size of the file. There is no mention of this in the text whatsoever. I see in the sample code that the implementation behind it is an exact duplicate of the file size code in the file overview controller. This is redundant and that makes it confusing. When I first tested my code, I thought it was broken b/c it didn't update the file size. Then I thought maybe I was supposed to pass the file size info somehow from the Overview to the Contents, since it had already been determined.

I suggest you remove this field from the view design, and remove the associated code from the sample.--Avram Dorfman

#39070: I am finding this chapter very frustrating. I'm currently on the section about reading the file asynchronously. You don't tell us anything about how to set up the FileContentsViewController, you only give us a couple of the methods. For example, you give us setUpAsynchronousContentLoad, but you don't tell us where to call it from. You also don't tell us how filePath ever gets set in the new FileContentViewController instance.

You also don't indicate that we should stop and check that our application works at this point. It's very difficult to check our work by having to compare to the sample code which includes everything through the end of the chapter, and having to sort out what we aren't supposed to have done yet from what we are supposed to have guess on our own that we were supposed to do even though you never mentioned it.--Avram Dorfman

#39143: wishy-washy: "Notice that the method takes a variable number of argu- ments for the "nor mal" buttons, and requires you to provide a final NULL argument to end the list of button titles. You also provide a delegate which will receive an actionSheet:clickedButtonAtIndex:5 callback."

You shouldn't tell me to "notice" this; at best it adds nothing, but really it implies I could have guessed how the API works. You are the expert, I'm the student, just tell me how it works. --Avram Dorfman

#39144: vague and incomplete: "You also provide a delegate which will receive an actionSheet:clickedButtonAtIndex: callback." This should be an instruction, not a commentary.

But what's much more important is that there are almost 60 lines of code behind this single sentence. It is not reasonable to expect the reader to guess that there is that much work to be done entirely on our own volition. If you don't want to discuss that code, that's fine, but at least point out that we should look at the implementation in the sample code. Personally unless you tell me to go to the sample, I assume (especially based on your training wheels comment earlier) that I am supposed to be able to figure everything out on my own that you do not spell out.--Avram Dorfman

#39140: The description of the new controller we need uses confusing terminology and non-obvious design. It doesn't make sense to say a controller "has" a button, graphical elements in MVC belong to views. Similarly, it doesn't make sense to say that a button "does x, y and z." All a button should really do in MVC is call a method on a controller. The controller is what's really doing all that work. I apologize if it sounds like I'm being pedantic, but I really had to struggle with this passage before I got it sorted out in my head and was then able to make these comments. Finally, it is not clear why we are creating the save button in code when we are building a whole view from scratch just for this. Why are we not creating the save button in IB?--Avram Dorfman

#39141: The following english is weak, misleading and inappropriately subtle: "Notice that we also need to alert the previous DirectoryViewController (a property in this class) to reload the directory contents and update its table view before we navigate back to it."

"Notice..." makes this whole thing a caveat, when really it needs to be it's on paragraph. You need to be decisive - instead of suggesting I notice something, tell me what I need to do. The parenthetical bit about the property needs to be the same way - tell me what to do and where. Also, "previous DirectoryViewController" is redundant and therefore inaccurate - "previous controller," or just "the DirectoryViewController."

For example, "We need a property in this class pointing to the DirectoryViewController, so we can alert it to reload its contents and update its view before we pop this view and return to it. We set this property <somehow>." --Avram Dorfman

#39052: Can I get a reference to my ZergSupport library in "more XML parsing options" please? My library makes it very easy (promise) to exchange data with Web services.

Currently, the first two results for googling "zergsupport" point to the code in GitHub, and to my blog post describing why I think it's useful. I'll be happy to provide hyperlinks if the Google searches don't work out for you.

Thanks!--Victor Marius Costan

#38309: Would it be possible to get more information on working with images? It'd really be helpful to have more information on things like image zoom and manipulation added. Information on dynamically loading images would really be helpful too.--Gregory Varghese

#39150: I have noticed numerous places where there is no comma after an introductory adverbial phrase - I believe there should be one and the pause I naturally make while reading it reinforces that belief.

Example on pg 253:
As is often the case the hard part is ...

I believe there should be a comma inserted after the word 'case'.
As is often the case, the hard part ....--Sandy North

#39574: In the box, change "the 3G iPhone has" to "almost every iPhone has". It is likely that future iPhones won't be properly described by "the 3G iPhone", but will have GPS.--Richard Smiley

#39570: I recommend elevating "Compass" to a numbered section (23.3). The compass is returning orientation information, so geometrically it is more closely related to the accelerometer than to location. It only belongs in Chapter 23 (as opposed to Chapter 21) because Apple made it part of the Core Location framework. A numbered section better reflects this dichotomy, and makes the compass visible in the Table of Contents.--Richard Smiley

#39576: The TouchXML bit seems out of place. Reading through the examples, I'd really rather see the part about "Selecting an annotation" before running off about geocoding.--Thomas Dimson

#39670: The section on TouchXML and the AddressGeocoder seems to be unfinished.

It only describes at length how to include the TouchXML but not about the AddressGeocoder implementation using TouchXML.

Also, I'd like you to elaborate on why you've chosen TouchXML this time versus NSXMLParser. The presented argument (we only need bits of information) by itself is not so convincing since in chapter 11 you were also only interested in partial information.--Miriam Busch

#39803: 1st para. Implies there is something we can do in how our app launches related to starting another app and returning to our app. Can we setup a return to our app? I want to send an SMS or EMAIL and return to my app when it is sent. If there is really no way to do this (I suspect this is true), the wording of the 1st paragraph might be changed. If there is, please share the technique.--Michael Riddle