I've got some code I want to only execute on the latest iPhone SDK (3.0), however I can't seem to figure out a way to target just 3.0 and ignore 2.2.1 etc. There is an ifdef statement, but it just seems to cover the entire iPhone:
#if TARGET_OS_IPHONE
Any help is appreciated.
You can use this #define to change what you build for each SDK...
#if __IPHONE_OS_VERSION_MIN_REQUIRED > __IPHONE_2_2
// iPhone 3.0 code here
#endif
And do this at run-time to run code for 3.0 and above:
float version = [[[UIDevice currentDevice] systemVersion] floatValue];
if (version >= 3.0)
{
// iPhone 3.0 code here
}
I'd be careful with the floatValue return result:
[[[UIDevice currentDevice] systemVersion] floatValue]
As with any floats, it may not be exactly what you expect. When running the above on my system, confused why my conditional statement wasn't executing, I noticed the value returned was:
3.20000005
Recommend the solutions here instead: How to check iOS version?
Excerpt:
NSComparisonResult order = [[UIDevice currentDevice].systemVersion compare: #"3.1.3" options: NSNumericSearch];
if (order == NSOrderedSame || order == NSOrderedDescending) {
// OS version >= 3.1.3
} else {
// OS version < 3.1.3
}
UPDATE: When building & running on iPhone (4.3.1) using Xcode 4, this no longer seems to work for me. Also, I get __IPHONE_OS_VERSION_MIN_REQUIRED = 30200.
The iPhone Developer's Cookbook says you can also do:
#ifdef _USE_OS_4_OR_LATER
// code to compile for 4.0 or later
#else
// code to compile for pre-4.0
#endif
And, it seems to work for me. :)
Pretty sure you can also do:
#ifdef __IPHONE_3_0
// 3.0 code here
#endif
It's in Xcode's build options. The drop down on the top left corner that says something like "myapp - 3.0 | Debug"
Select the build you want and presto, your done.
Using the trick of adding OTHER_CFLAGS = "-g3 -save-temps -dD" from this answer, I found that the define __IPHONE_OS_VERSION_MIN_REQUIRED 20000 with a project targeted at 2.2.1. Perhaps that will work?
I'm fairly certain that the comment on the OP sums it up. You can't. Because a compile time directive cannot make a run-time decision. In Xcode, if you target 3.0, it won't run on a 2.2.1 phone. If you target 2.2.1, it won't compile because you have 3.0 specific code in there.
The only true solution would be two versions of your app, one of which is compiled for 3.0, and the other for 2.2.1.
Well, my two cents:
How about building your app with the latest version say 3.0 so you can exploit all the new & cool APIs and specifying the Deployment Target as the least recent version you want to support so guys out there who didn't take time out to upgrade their devices will stil run your app. In this case as shown above you need to check for least recent version of the SDK and provide alternate functionality to make your application backward compatible.
Regards,
Hardik
Related
I am trying to implement the background mode with async socket.
The following are a few codes:
CFReadStreamRef theReadStream;
CFWriteStreamRef theWriteStream;
if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 4.0) {
CFReadStreamSetProperty (theReadStream, kCFStreamNetworkServiceType, kCFStreamNetworkServiceTypeVoIP);
CFWriteStreamSetProperty(theWriteStream, kCFStreamNetworkServiceType, kCFStreamNetworkServiceTypeVoIP);
}
I know kCFStreamNetworkServiceType and kCFStreamNetworkServiceTypeVoIP are available in iPhone with iOS started at 4.0.
The above codes were workable indeed when I built into iPhone with iOS started at 4.0.
However, I could not build the above codes into iPhone with iOS 3.1 successfully.
I have added the statement, ([[[UIDevice currentDevice] systemVersion] floatValue] >= 4.0), to the above codes.
I don't know why I could not enter the program at all especially I have added the if statement.
I think you are getting compile time error because you are using kCFStreamNetworkServiceType and kCFStreamNetworkServiceTypeVoIP in your code which is not available in iOS 3.1. Its available in iOS 4.0 onwards. So you should use #if kind of macros to get rid of that error. Hope that helps to you.
I am just started write app for ios.
I have 2 questions.
I know there are some codes which work fine in ios4.3 but don't work in ios5 and the opposite is also true.I want to know,which is the best practice for writing app both for ios4.3 and ios5?Is it acceptable run-time to check the version for specific parts of code??
I am also should write same app for ipad. So, I want to know which is the best practice for writing app for iphone which works also on ipad??
Thanks
iOS 5 or iOS 4
Another way to detect the version is to use the respondsToSelector: message on objects. The advantage compared to the version method is that you don't need to know what the next versions of iOS are gonna be to maintain your application. (What if, for instance, a new 5.0.2 version shows up? Your app should know that the "5.0.2" string is newer than "5.0"? I agree it would not be complicated to code, but using respondsToSelector: is much more convenient)
iPhone/iPod Touch or iPad
My usual way to code universal app (ie iPhone and iPad) is to define a basic implementation of my custom UIViewController classes, and then implement an HD version of it, inheriting the default behavior but customizing it for the iPad (overriding methods works well but the delegate pattern might be better: you get compilation warnings if you forget to implement methods).
If you use a different .xib file from the beginning of your application lifecycle (that's what you get by universal Xcode-provided templates), you may end up defining classes just from Interface Builder, and won't need to implement any runtime test in your code to know if you're running on an iPhone or an iPad.
You can get the version using:
[[UIDevice currentDevice] systemVersion];
The systemVersion returns a string, like "5.0". You can then compare the strings using string comparison. For example:
NSString *requiredVersion = #"5.0";
NSString *currentVersion = [[UIDevice currentDevice] systemVersion];
if ([currentVersion compare:requiredVersion options:NSNumericSearch] != NSOrderedAscending)
isItSupported = TRUE;
The documentation indicates that you can use the following to determine if you have an iPhone or iPad:
[[UIDevice currentDevice] model];
I've not used this though.
See the documentation.
i'm trying to add printing features to an ios app.
while printing itself works fine, and the app works on ios > 4, i haven't figured out yet how to keep the ios 3.1 compatibility...
i guess the issue is this: completionHandler:(UIPrintInteractionCompletionHandler)
A block of type UIPrintInteractionCompletionHandler that you implement to handle the
conclusion of the print job (for instance, to reset state) and to
handle any errors encountered in printing.
once i add the block:
void (^completionHandler)(UIPrintInteractionController *, BOOL, NSError *) =
^(UIPrintInteractionController *printController, BOOL completed, NSError *error) {
};
the app won't even launch on iOS 3.1
probably because blocks aren't available there.
yes, i made sure that this code won't be run when launched on iOS 3.1...
if (([[[UIDevice currentDevice] systemVersion] floatValue] >= 4.2) && ([UIPrintInteractionController isPrintingAvailable]))
so i wonder if there's a way to have printing support for iOS >4.2, but keeping it to run on iOS 3.1?
maybe there's a way to use a method instead of the "block"?
or how would be the correct way to have printing available on supported iOS devices, and remain backwards compatible to iOS 3.1?
just add -weak_framework UIKit to the project settings under "Other Linker Flags" and make sure you use conditional code for printing API.
Conditional code should check feature availability, not OS version:
if (NSClassFromString(#"UIPrintInteractionController")){
void (^completionHandler)(UIPrintInteractionController *, BOOL, NSError *) =
^(UIPrintInteractionController *printController, BOOL completed, NSError *error) {
};
}
Set your project target to iOS 3, and you're good to go.
The best practice for detecting if AirPrint is available is to use NSClassFromString. If you use this method in general, then you always know if exactly the class you want is available, without having to hard-code which features correspond with which version. Example code:
Class printControllerClass = NSClassFromString(#"UIPrintInteractionController");
if (printControllerClass) {
[self setupCanPrintUI];
} else {
[self setupCannotPrintUI];
}
That way your app can still work on previous iOS versions, although it won't be able to print from them.
I've been able to use this technique and run it on an iOS 3.0 device without any problems with the block code (the ^-based stuff). In my build settings, I have the Base SDK set to iOS 4.2, and the Deployment Target set to iOS 3.0.
I posted a sample Xcode project at the end of this blog post on printing in iOS. This is the project that successfully runs for me on a device with iOS 3.0 and another device with iOS 4.2. You may have to change the bundle identifier in the info.plist to get the code-signing to work for you, but that's independent of the printing stuff.
Set Deployment Target in your Project Settings to iOS 3.x. However, set the Base SDK to 4.2. Now you can use the 4.2 classes and iPhones running 3.x can install your app too.
Keep in mind that when you use a 4.2 class on an iPhone 3.x, the application will crash (so keep checking the system version on-the-go).
NSComparisonResult order = [[UIDevice currentDevice].systemVersion compare:#"3.2" options: NSNumericSearch];
if (order == NSOrderedSame || order == NSOrderedDescending && [[UIDevice currentDevice]isMultitaskingSupported]) {
// >4.2
}
else {
//< 4.2
}
Note:
also change UIKit framework setting from "required" to "weak" this will help you to run application on iOs < 4.2 as well as iOs >= 4.2
I have a code for UIImage picker
photoImagePicker=[[UIImagePickerController alloc]init];
photoImagePicker.delegate=self;
photoImagePicker.sourceType=UIImagePickerControllerSourceTypeCamera;
photoImagePicker.mediaTypes=[UIImagePickerController availableMediaTypesForSourceType:photoImagePicker.sourceType];
[self presentModalViewController:photoImagePicker animated:YES];
photoImagePicker.showsCameraControls = YES; //Doesnot work on 3.0
photoImagePicker.navigationBarHidden = YES;
photoImagePicker.toolbarHidden = YES;
photoImagePicker.allowsEditing=YES; //Doesnt work on 3.0
Now everything works fine when the sdk is 3.1 or higher but when i put the os version as 3.0, the code starts showing errors. Turns out these methods were not present in 3.0 and so errors. I want to keep a mechanism which will enable these for higher versions(3.1) and at the same time work properly for 3.0 version.
How do i do it?
One solution i have thought of is to verify the version value and then put that code. But i am not sure how this is got. Any help will be appreciated.
I think you should be able to do it using Weak Linking. This article How to build a single iPhone application support both 2.x and 3.0 at the same time should also help.
I'm working on a new app that I want to be universal for the iPhone and iPad. I started out with the "Create a Window-based app" wizard, and it created separate app delegates in "iPhone" and "iPad" groups. Since I already was quite familiar with iPhone dev, I did that part of my project, and now I'm ready to do some iPad stuff.
So... I started out by adding a UISplitViewController to my iPad delegate, switch the Active SDK to 3.2, and it works! But when I switch back to 3.1.3, and try to run it in the simulator, Build and Go fails. For starters, I see:
...path.../iPad/AppDelegate_Pad.h:13: error: expected specifier-qualifier-list before 'UISplitViewController'
I've got my Base SDK set to 3.2 and my Deployment Target set to 3.1.3. I thought that was enough. But I also have found in the documentation this method to conditionally compile:
#if __IPHONE_OS_VERSION_MAX_ALLOWED >= 30200
MyIPadViewController* vc;
// Create the iPad view controller
#else
MyIPhoneViewController* vc;
// Create the iPhone view controller
#endif
So do I need to do this everywhere? It seems like an awful lot of code to add (that I'll be getting rid of in a short time for 4.0 anyway) so I feel like I must be doing something wrong. And, I don't even have any idea how this works for things like #property or #synthesize declarations.
tl;dr version of the question - did I miss a setting somewhere?
I use this C function to help keep the code concise:
BOOL isPad() {
return (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad);
}
Another thing I do, when I have different xib files for iPhone vs iPad. I have a stripPadSuffixOnPhone() function that helps keep the code simpler:
// Load/create the Delete table cell with delete button
self.deleteCell = [Utilities loadNib:stripPadSuffixOnPhone(#"DeleteCell~ipad")
ClassName:#"DeleteCell"
Owner:self];
Things like that can make coding more straightforward and a lot less conditionals. Still have to test everything twice though.
Quite the opposite. A universal app runs the same binary on iPhone and iPad so you cannot use conditional compilation to differentiate between the two version. But you need to use the macro Apple cites in the documentation:
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
// iPad-specific code
} else {
// iPhone-specific code
}
Here's what works for me:
Build your app using SDK 3.2.
Switch the active SDK to iPhone Simulator 3.1.3 (or whatever).
From the Run menu select Debug (not Build and Debug).
The binary built under 3.2 will be installed in the 3.x simulator without rebuilding. When you are finished don't forget to set your active SDK back to 3.2.