A UIImage has a property imageOrientation, which instructs the UIImageView and other UIImage consumers to rotate the raw image data. There’s a good chance that this flag is being saved to the exif data in the uploaded jpeg image, but the program you use to view it is not honoring that flag. To rotate the … Read more
As Kevin points out, URL Schemes are the only way to communicate between apps. So, no, it’s not possible to launch arbitrary apps. But it is possible to launch any app that registers a URL Scheme, whether it’s Apple’s, yours, or another developer’s. The docs are here: Defining a Custom URL Scheme for Your App … Read more
Attempt to present UIViewController on UIViewController whose view is not in the window hierarchy
Vertically align text to top within a UILabel
If you see this warning: warning: receiver ‘MyCoolClass’ is a forward class and corresponding @interface may not exist you need to #import the file, but you can do that in your implementation file (.m), and use the @class declaration in your header file. @class does not (usually) remove the need to #import files, it just … Read more
Restrictions If you could send an SMS within a program on the iPhone, you’ll be able to write games that spam people in the background. I’m sure you really want to have spams from your friends, “Try out this new game! It roxxers my boxxers, and yours will be too! roxxersboxxers.com!!!! If you sign up … Read more
How do I size a UITextView to its content?
If you use the underscore prefix for your ivars (which is nothing more than a common convention, but a useful one), then you need to do 1 extra thing so the auto-generated accessor (for the property) knows which ivar to use. Specifically, in your implementation file, your synthesize should look like this: @synthesize missionName = … Read more
File type handling is new with iPhone OS 3.2, and is different than the already-existing custom URL schemes. You can register your application to handle particular document types, and any application that uses a document controller can hand off processing of these documents to your own application. For example, my application Molecules (for which the … Read more
FYI, I combined Keremk’s answer with my original outline, cleaned-up the typos, generalized it to return an array of colors and got the whole thing to compile. Here is the result: + (NSArray*)getRGBAsFromImage:(UIImage*)image atX:(int)x andY:(int)y count:(int)count { NSMutableArray *result = [NSMutableArray arrayWithCapacity:count]; // First get the image into your data buffer CGImageRef imageRef = [image … Read more