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Defining legal input characters
January 02 2009
I sometimes use a little trick to ensure that a UITextInputField only accepts a certain subset of characters. Say for example, you want to ensure that a user enters only letters and spaces. A UITextField delegate can catch each character as its typed and decide whether to add items to… read moreUseful Core Graphics functions
December 26 2008
Last week, I introduced several handy utilities that let you convert standard Core Graphics structures to and from strings. This week, I thought I'd continue to explore utility functions, moving on to ways you can work with points and rectangles for on-screen calculations. Like the string utilities, these are functions,… read moreConverting Points and Rectangles to Strings and back
December 19 2008
Two core graphics structures, the CGRect and the CGPoint, play a large role in iPhone development. They are used to position items on-screen and to set their size. Every time you use a UIView, you can work with its frame, its center, and its bounds--all of which use these two… read moreConverting Points and Rectangles to Strings and back
December 19 2008
Two core graphics structures, the CGRect and the CGPoint, play a large role in iPhone development. They are used to position items on-screen and to set their size. Every time you use a UIView, you can work with its frame, its center, and its bounds--all of which use these two… read moreDecember 12 2008
In the beginning, or at least the iPhone's beginning, there was Celestial. It offered a fabulous QuickTime-esque approach to handling media of all kinds. Of course, this was back in the days of the first jailbreaks and there was no official SDK. When the SDK finally did roll around, its… read moreDecember 12 2008
In the beginning, or at least the iPhone's beginning, there was Celestial. It offered a fabulous QuickTime-esque approach to handling media of all kinds. Of course, this was back in the days of the first jailbreaks and there was no official SDK. When the SDK finally did roll around, its… read moreThe case of the Missing MapKit
December 05 2008
While wading through the new 2.2 Frameworks, I suddenly noticed that MapKit, once a Private Framework was missing in action. MapKit, which was available until SDK 2.1, offered all kinds of utterly yummy features including Trip Players, Traffic tiles, Route Views and more. So what happened to MapKit? read moreThe case of the Missing MapKit
December 05 2008
While wading through the new 2.2 Frameworks, I suddenly noticed that MapKit, once a Private Framework was missing in action. MapKit, which was available until SDK 2.1, offered all kinds of utterly yummy features including Trip Players, Traffic tiles, Route Views and more. So what happened to MapKit? read moreLocating, tagging, and retrieving views
November 28 2008
Last week, I wrote about exploring subviews both of the user-added and Apple-created varieties. Many GUI components contain view classes that are hidden from the developer but are composed of perfectly standard components. read moreLocating, tagging, and retrieving views
November 28 2008
Last week, I wrote about exploring subviews both of the user-added and Apple-created varieties. Many GUI components contain view classes that are hidden from the developer but are composed of perfectly standard components. read moreView Spelunking Part 1: Exploring subviews and layout
November 21 2008
It's often helpful to take a look at your UIView hierarchy; and when I say "look", I mean all the way down. You can just as easily look at the component subviews that comprise on-screen objects like buttons, switches, and sliders, as you can at the UIImageViews and UIButtons that… read moreView Spelunking Part 1: Exploring subviews and layout
November 21 2008
It's often helpful to take a look at your UIView hierarchy; and when I say "look", I mean all the way down. You can just as easily look at the component subviews that comprise on-screen objects like buttons, switches, and sliders, as you can at the UIImageViews and UIButtons that… read moreNovember 14 2008
One of the things I hate about the Media Player framework is that although it offers easy-to-use audio playback, it does so horizontally. Users have to flip their phones onto the side and access the playback controls in landscape. It's not all that hard to force Media Player into portrait… read moreHunting down Info.plist Preferences
November 07 2008
I've spent some time recently trying to hunt down items for use in your Info.plist files. The natural place to look for these is the SpringBoard executable in the iPhone's Core Services folder. I ran this file through a strings filter, looking to see if I could find groupings of… read moreNovember 01 2008
A view that handles multiple touch points must announce itself. Add the isMultipleToucheEnabled handler and have it return YES. Doing so allows your touch methods (touchesBegan, touchesMoved, touchesEnded) to work with several touchpoints at once. read more
