我创建了一个在 5.0 及更高版本上运行良好的应用程序，但是当我在较低的设备上进行测试时，我遇到了一些我不确定如何解决和纠正的问题。
第一个大问题是当保存到核心数据时，我使用了一个错误方法，我相信这是苹果在创建核心数据模型时创建的默认错误方法。该应用程序在低于 5.0 时崩溃，但如果我屏蔽错误代码，一切正常。下面是用于查找错误和处理它的代码。
NSError *error;
if (![managedObjectContext save:&error]) { // crash here
// This is a serious error saying the record could not be saved.
// Advise the user to restart the application
}
//下面的崩溃日志
2012-05-13 10:17:22.062 PreviewMaker[41595:207] -[UIImage encodeWithCoder:]:
unrecognized selector sent to instance 0x5e7ce80
2012-05-13 10:17:22.064 PreviewMaker[41595:207] *** Terminating app due to uncaught
exception 'NSInvalidArgumentException', reason: '-[UIImage encodeWithCoder:]:
unrecognized selector sent to instance 0x5e7ce80'
*** Call stack at first throw:
(
0 CoreFoundation 0x013fc5a9 __exceptionPreprocess + 185
1 libobjc.A.dylib 0x0178b313 objc_exception_throw + 44
2 CoreFoundation 0x013fe0bb -[NSObject(NSObject)
doesNotRecognizeSelector:] + 187
3 CoreFoundation 0x0136d966 ___forwarding___ + 966
4 CoreFoundation 0x0136d522 _CF_forwarding_prep_0 + 50
5 Foundation 0x00c45b3e _encodeObject + 1076
6 Foundation 0x00c50f89 +[NSKeyedArchiver
archivedDataWithRootObject:] + 206
7 CoreData 0x01122cb5 -[NSSQLiteConnection execute] +
2677
8 CoreData 0x011771d6 -[NSSQLiteConnection insertRow:]
+ 262
9 CoreData 0x01173e64 -[NSSQLConnection
performAdapterOperations:] + 180
10 CoreData 0x01173b0e -[NSSQLCore
_performChangesWithAdapterOps:] + 494
11 CoreData 0x011725ea -[NSSQLCore performChanges] + 410
12 CoreData 0x0116c038 -[NSSQLCore saveChanges:] + 216
13 CoreData 0x0112a199 -[NSSQLCore
executeRequest:withContext:error:] + 409
14 CoreData 0x011da70b -[NSPersistentStoreCoordinator
executeRequest:withContext:error:] + 3691
15 CoreData 0x01162948 -[NSManagedObjectContext save:] +
712
16 PreviewMaker 0x0000a0c0 -[MainViewController
noUploadJustSaveImage:] + 331
17 PreviewMaker 0x00009d3c -[MainViewController
UserConfirmedToSaveImage] + 756
18 UIKit 0x004774fd -[UIApplication
sendAction:to:from:forEvent:] + 119
19 UIKit 0x00507799 -[UIControl
sendAction:to:forEvent:] + 67
20 UIKit 0x00509c2b -[UIControl(Internal)
_sendActionsForEvents:withEvent:] + 527
21 UIKit 0x005087d8 -[UIControl
touchesEnded:withEvent:] + 458
22 UIKit 0x0049bded -[UIWindow _sendTouchesForEvent:]
+ 567
23 UIKit 0x0047cc37 -[UIApplication sendEvent:] + 447
24 UIKit 0x00481f2e _UIApplicationHandleEvent + 7576
25 GraphicsServices 0x01eb8992 PurpleEventCallback + 1550
26 CoreFoundation 0x013dd944
__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 52
27 CoreFoundation 0x0133dcf7 __CFRunLoopDoSource1 + 215
28 CoreFoundation 0x0133af83 __CFRunLoopRun + 979
29 CoreFoundation 0x0133a840 CFRunLoopRunSpecific + 208
30 CoreFoundation 0x0133a761 CFRunLoopRunInMode + 97
31 GraphicsServices 0x01eb71c4 GSEventRunModal + 217
32 GraphicsServices 0x01eb7289 GSEventRun + 115
33 UIKit 0x00485c93 UIApplicationMain + 1160
34 PreviewMaker 0x00002e07 main + 121
35 PreviewMaker 0x00002d85 start + 53
)
terminate called after throwing an instance of 'NSException'
我遇到的另一个问题是设置tintColorUI 对象，例如UISwitch. 我有一个设置控制器，它有几个UISwitches 等，几乎都设置了 tint 颜色，但是一旦低于 5.0 的任何东西都崩溃了。我如何处理这两者而不必为了与 5.0 以下的设备兼容而重新编写代码。
shineSwitch = [[[UISwitch alloc] initWithFrame:CGRectZero] autorelease];
[cell.contentView addSubview:shineSwitch];
cell.accessoryView = shineSwitch;
[shineSwitch addTarget:self action:@selector(switchChanged:)
forControlEvents:UIControlEventValueChanged];
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
shineSwitch.onTintColor = [UIColor colorWithRed:0.0 green:0.61 blue:0.99 alpha:1.0];
//下面的崩溃日志
2012-05-13 10:19:45.033 PreviewMaker[41611:207] -[UISwitch setOnTintColor:]:
unrecognized selector sent to instance 0x5eab860
2012-05-13 10:19:45.034 PreviewMaker[41611:207] *** Terminating app due to uncaught
exception 'NSInvalidArgumentException', reason: '-[UISwitch setOnTintColor:]:
unrecognized selector sent to instance 0x5eab860'
*** Call stack at first throw:
(
0 CoreFoundation 0x013fc5a9 __exceptionPreprocess + 185
1 libobjc.A.dylib 0x0178b313 objc_exception_throw + 44
2 CoreFoundation 0x013fe0bb -[NSObject(NSObject)
doesNotRecognizeSelector:] + 187
3 CoreFoundation 0x0136d966 ___forwarding___ + 966
4 CoreFoundation 0x0136d522 _CF_forwarding_prep_0 + 50
5 PreviewMaker 0x0000f6fb -[FlipsideViewController
tableView:cellForRowAtIndexPath:] + 1353
6 UIKit 0x004ecb98 -
[UITableView(UITableViewInternal) _createPreparedCellForGlobalRow:withIndexPath:] + 634
7 UIKit 0x004e24cc -
[UITableView(UITableViewInternal) _createPreparedCellForGlobalRow:] + 75
8 UIKit 0x004f78cc -
[UITableView(_UITableViewPrivate) _updateVisibleCellsNow:] + 1561
9 UIKit 0x004ef90c -[UITableView layoutSubviews] +
242
10 QuartzCore 0x001e2a5a -[CALayer layoutSublayers] + 181
11 QuartzCore 0x001e4ddc CALayerLayoutIfNeeded + 220
12 QuartzCore 0x0018a0b4
_ZN2CA7Context18commit_transactionEPNS_11TransactionE + 310
13 QuartzCore 0x0018b294 _ZN2CA11Transaction6commitEv +
292
14 QuartzCore 0x0018b46d
_ZN2CA11Transaction17observer_callbackEP19__CFRunLoopObservermPv + 99
15 CoreFoundation 0x013dd89b
__CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 27
16 CoreFoundation 0x013726e7 __CFRunLoopDoObservers + 295
17 CoreFoundation 0x0133b1d7 __CFRunLoopRun + 1575
18 CoreFoundation 0x0133a840 CFRunLoopRunSpecific + 208
19 CoreFoundation 0x0133a761 CFRunLoopRunInMode + 97
20 GraphicsServices 0x01eb71c4 GSEventRunModal + 217
21 GraphicsServices 0x01eb7289 GSEventRun + 115
22 UIKit 0x00485c93 UIApplicationMain + 1160
23 PreviewMaker 0x00002e07 main + 121
24 PreviewMaker 0x00002d85 start + 53
)
terminate called after throwing an instance of 'NSException'
任何帮助将不胜感激！