Posts Tagged 'Programming'

Having trouble with your UITextViews getting stuck under the keyboard? Here’s an elegant approach:

The iPhone’s onscreen keyboard occupies the bottom 216 pixels on screen (140 in landscape mode). That’s around half the screen, so if you ever have a text field you want to edit in the bottom half of the screen, it needs to move or it will get covered.

You can just animate the whole window upwards by the height of the keyboard when editing a text field in the bottom half but this doesn’t work well for text fields in the middle (they can get moved too far up).

Instead, I’m going to show you a method which divides the window as follows:

Everything in the top section will stay still when edited. Everything in the middle section will animate upwards by a fraction of the keyboard’s height (proportional to the field’s height within the middle section). Everything in the bottom section will animate upwards by the keyboard’s full height.

Much prettier than just jumping stuff around, indeed. And hey, it’s all about the pretty, isn’t it?

Whilst we quite firmly believe that every second you spend implementing copy protection instead of things that, you know, actually make people want to buy your application are a striking misallocation of development resources, life as a contract programmer means that you do what your customers want, and it seems to be an unfortunate general rule that people are much more interested in upping the challenge and therefore the attraction for people who aren’t going to buy the application anyway than they are in actually making the application more attractive to people who will pay.

But perhaps we are unduly cynical.

Any-how, should you find yourself in the position of being tasked with implementing copy protection on an iPhone application, our condolences, and here is a snippet which may be of use.

#if HEARTBEAT_CHECK_PIRACY
+ (BOOL)isCracked {
#if TARGET_IPHONE_SIMULATOR
        return NO;
#else
        static BOOL isCracked = NO;
        static BOOL didCheck = NO;
        if(didCheck) return isCracked;
#if HEARTBEAT_PIRACY_THRESHOLD >= 1
   if([[[NSBundle mainBundle] infoDictionary] objectForKey:@"SignerIdentity"] != nil) {
              #if HEARTBEAT_PIRACY_THRESHOLD >= 2
              NSString* infoPath = [[NSBundle mainBundle] pathForResource:@"Info" ofType:@"plist"];
              if([[NSString stringWithContentsOfFile:infoPath encoding:NSUTF8StringEncoding error:NULL] rangeOfString:@"</plist>"].location != NSNotFound) {
                        #if HEARTBEAT_PIRACY_THRESHOLD >= 3
                      NSDate* infoModifiedDate = [[[NSFileManager defaultManager] fileAttributesAtPath:infoPath traverseLink:YES] fileModificationDate];
                 NSDate* pkgInfoModifiedDate = [[[NSFileManager defaultManager] fileAttributesAtPath:[[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"PkgInfo"] traverseLink:YES] fileModificationDate];
                  if([infoModifiedDate timeIntervalSinceReferenceDate] > [pkgInfoModifiedDate timeIntervalSinceReferenceDate]) {
                     #endif
              #endif
                              isCracked = YES;
           #if HEARTBEAT_PIRACY_THRESHOLD >= 2
                      #if HEARTBEAT_PIRACY_THRESHOLD >= 3
                      }
                  #endif
              }
          #endif
      }
#endif
      didCheck = YES;
  return isCracked;
#endif
}
#endif

We have no intention of bothering to actually implement it on our own initiative, so this isn’t a recommendation per se, but hey, it looks like it has a chance of working, so if you want something like that, there you go!

[EDIT: And here is a strategy for dealing with crack detection which has some smidgen of sensibility to it.]

Here’s a good project on Google Code to bookmark in case you ever need to do any image processing tasks with UIImage:

I’ve written a simple C++ class with an Objective-C wrapper that provides a set of common image processing tasks along with conversion to and from UIImage.

The code supports the following operations:

• Canny edge detection - http://en.wikipedia.org/wiki/Canny_edge_detection
• Histogram equalisation - http://en.wikipedia.org/wiki/Histogram_equalisation
• Skeletonisation - http://en.wikipedia.org/wiki/Topological_skeleton
• Thresholding, adaptive and global - http://en.wikipedia.org/wiki/Thresholding_(image_processing)
• Gaussian blur (used as a preprocessing step for canny edge detection) - http://en.wikipedia.org/wiki/Gaussian_blur
• Brightness normalisation - http://en.wikipedia.org/wiki/Normalization_(image_processing)
• Connected region extraction - http://en.wikipedia.org/wiki/Blob_extraction
• Resizing – uses interpolation

Beats writing all that of scratch, indeed!

h/t: iPhone Development!

Isn’t it annoying when you do your Ad Hoc distributions that your pretty application icon doesn’t show up in iTunes? Well, here’s the trick — fake yourself a folder that looks like an iTunes distribution:

iPhone developer Malcolm Hall explained how he sets up his Ad Hoc applications so they’ll display the proper image. He creates a folder in which he places two items: the first is a JPEG image called iTunesArtwork, the second is a folder called Payload. He adds the app bundle (Whatever.app) into the Payload subfolder, zips up the entire thing and renames the zip file toAppname.ipa.

This ipa package (ipa stands for iPhone application) mimics the way that Apple provides applications for iTunes. When iTunes sees the iTunesArtwork file, it uses it to create the image seen in the Applications library.

The iTunesArtwork file should be added without an explicit extension. Hall suggests you use Get Info (Command-I) and remove the file extension before zipping it up. (You can also remove the extension at the command line.) Use a 512×512 image for the art.

Which describes the layout

- yourapp.ipa (zip renamed to ipa for iPhone Application)
        - iTunesArtwork (512x512 JPEG with no extension)
        - Payload (Folder)
                - yourapp.app (as produced by Xcode)

There you go. Now you can look properly professional with your Ad Hoc distributions! And it’s all about the looks, isn’t it now?