ios4

问题 How do I get arctan MATH function in iphone SDK? 回答1: The function you are looking for is atan(double) 回答2: Use the "2nd"-function under the "("-key, top left with the iphone in horizontal position. The tan key will change to tan-1, i.e. arctan. 来源： https://stackoverflow.com/questions/5339595/how-do-i-get-arctan-math-function-in-ios

问题 What is the different between, (CFDataRef) data & (__bridge CFDataRef) data Xcode asked me to change it to bridge. Is that because of ARC? 回答1: Yes, ARC needs to be given instructions when you cast between toll-free bridged types. In this case __bridge tells ARC to do nothing, so this will behave the same as the previous standard cast. You can read the Transitioning to ARC Release Notes for more details on the different ways to do bridging casts. 来源： https://stackoverflow.com/questions

问题 As many people are complaining it seems that in the Apple SDK for the Retina Display there's a bug and imageWithContentsOfFile actually does not automatically load the 2x images. I've stumbled into a nice post how to make a function which detects UIScreen scale factor and properly loads low or high res images ( http://atastypixel.com/blog/uiimage-resolution-independence-and-the-iphone-4s-retina-display/ ), but the solution loads a 2x image and still has the scale factor of the image set to 1

问题 Does anyone know any knowledge of using this: - (void) startMonitoringForRegion:(CLRegion *)region desiredAccuracy:(CLLocationAccuracy)accuracy I am trying to implement it into my project but: - (void) locationManager:(CLLocationManager *)manager didEnterRegion:(CLRegion *)region is never being called? Does anyone have any example code or know why this is happening? My code is as follows. I created a method like this in my own LocationManager class: - (void)

问题 Does anyone know any knowledge of using this: - (void) startMonitoringForRegion:(CLRegion *)region desiredAccuracy:(CLLocationAccuracy)accuracy I am trying to implement it into my project but: - (void) locationManager:(CLLocationManager *)manager didEnterRegion:(CLRegion *)region is never being called? Does anyone have any example code or know why this is happening? My code is as follows. I created a method like this in my own LocationManager class: - (void)

问题 I've figured out how I can get audio playing in the background on ios4, however I've noticed that some apps also replace the iPod dock icon with their own app icon. (Last.fm & Spotify for example). They are also able to use the dock media controls to pause and resume their streams. Does anyone know how to do this? Thanks 回答1: It's easy you have to respond to the Remote Control Events. This also lets you control your app with the headset. In lets say viewDidLoad call: [[UIApplication

问题 I already have the base code that supports ios 4.3 to ios 5. Now I would also like to support ios 6.0. The present base code has modal views , hard coded CGRect's , and rotation is different for each view. So I would like to know whether we can support ios 4.3 to ios 6.0 with the same base code, by just tweaking some changes, or do we need to create a complete new target? Like we cannot use auto layout of ios 6.0 if I want to support previous versions as it will lead to a crash. 回答1: Yes, we

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 4 years ago . I was wondering if anyone knows where I can find documentation or a tutorial on how to make a vertical tab bar for iOS like in 1Password or 2do. I figure that these aren't "real" tab bars, but I'd really like to use that functionality and I'm at a loss on how to accomplish it. Thanks in advance for any help! 回答1

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 4 years ago . I was wondering if anyone knows where I can find documentation or a tutorial on how to make a vertical tab bar for iOS like in 1Password or 2do. I figure that these aren't "real" tab bars, but I'd really like to use that functionality and I'm at a loss on how to accomplish it. Thanks in advance for any help! 回答1

问题 Want to know whether its possible to change the time of the iPhone through an application.. Is that level of dev access granted in iOS4? My gut feeling is no, but I'm looking for a definitive Yes/No answer if possible. Note: NSTimeZone class states 'Cocoa does not provide any API to change the time zone of the computer, or of other applications.' Thanks.. 回答1: No this functionality is not possible via the official iphone SDK. 来源： https://stackoverflow.com/questions/3121287/can-we-change-the