我是一个正在学习OC的新手 .
但是现在当我将一个插座按钮设置为我的viewcontroller的属性时，为了为它添加一个属性，当我在 viewDidLoad 中编写一些方法时，发生了类似这样的错误：
我唯一想做的就是设置 outLetButton.currentTitle 的属性
我的代码如下：
我的按钮没有问题 .
(void)viewDidLoad {
[super viewDidLoad];
/
NSMutableAttributedString * title = [[NSMutableString alloc] initWithString:self.OutletButton.currentTitle] ;
[title setAttributes:@{NSStrokeWidthAttributeName:@3.0,NSStrokeColorAttributeName:[self.OutletButton tintColor]} range:NSMakeRange(0, [title length])] ;
[self.OutletButton setAttributedTitle:title forState:UIControlStateNormal] ;
}
我使用突破性调试，当我跨过 [title setAttributes...] 时，它崩溃了 .
First throw call stack
0 CoreFoundation 0x000000010ba0b12b __exceptionPreprocess 171
1 libobjc.A.dylib 0x000000010b09ff41 objc_exception_throw 48
2 CoreFoundation 0x000000010ba8c024 - [NSObject（NSObject）doesNotRecognizeSelector：] 132
3 CoreFoundation 0x000000010b98df78 forwarding 1432
4 CoreFoundation 0x000000010b98d958 _CF_forwarding_prep_0 120
5 UITextView 0x000000010a791106 - [ViewController viewDidLoad] 598
6 UIKit 0x000000010c03146c - [UIViewController loadViewIfRequired] 1235
7 UIKit 0x000000010c0318b9 - [UIViewController视图] 27
8 UIKit 0x000000010befc7cf - [UIWindow addRootViewControllerViewIfPossible] 122
9 UIKit 0x000000010befced7 - [UIWindow _setHidden：forced：] 294
10 UIKit 0x000000010bf0fe54 - [UIWindow makeKeyAndVisible] 42
11 UIKit 0x000000010be828b8 - [UIApplication _callInitializationDelegatesForMainScene：transitionContext：] 4737
12 UIKit 0x000000010be87aeb - [UIApplication _runWithMainScene：transitionContext：completion：] 1720
13 UIKit 0x000000010c2516f8 __111 - [__ UICanvasLifecycleMonitor_Compatability _scheduleFirstCommitForScene：transition：firstActivation：completion：] _ block_invoke 924
14 UIKit 0x000000010c6274c8 [_UICanvas _enqueuePostSettingUpdateTransactionBlock：] 153
15 UIKit 0x000000010c2512f1 - [__ UICanvasLifecycleMonitor_Compatability _scheduleFirstCommitForScene：transition：firstActivation：completion：] 249
16 UIKit 0x000000010c251b6b - [__ UICanvasLifecycleMonitor_Compatability activateEventsOnly：withContext：completion：] 696
17 UIKit 0x000000010cbcfa69 __82 - [_ UIApplicationCanvas _transitionLifecycleStateWithTransitionContext：completion：] _ block_invoke 262
18 UIKit 0x000000010cbcf922 - [_ UIApplicationCanvas _transitionLifecycleStateWithTransitionContext：completion：] 444
19 UIKit 0x000000010c8ac9c8 __125 - [_ UICanvasLifecycleSettingsDiffAction performActionsForCanvas：withUpdatedScene：settingsDiff：fromSettings：transitionContext：] _ block_invoke 221
20 UIKit 0x000000010caabb06 _performActionsWithDelayForTransitionContext 100
21 UIKit 0x000000010c8ac88b - [_ UICanvasLifecycleSettingsDiffAction performActionsForCanvas：withUpdatedScene：settingsDiff：fromSettings：transitionContext：] 231
22 UIKit 0x000000010c626b25 - [_ UICanvas场景：didUpdateWithDiff：transitionContext：completion：] 392
23 UIKit 0x000000010be8636a - [UIApplication workspace：didCreateScene：withTransitionContext：completion：] 523
24 UIKit 0x000000010c461605 - [UIApplicationSceneClientAgent场景：didInitializeWithEvent：完成：] 369
25 FrontBoardServices 0x0000000110158cc0 - [FBSSceneImpl _didCreateWithTransitionContext：completion：] 338
26 FrontBoardServices 0x00000001101617b5 __56- [FBSWorkspace客户端：handleCreateScene：withCompletion：] _ block_invoke_2 235
27 libdispatch.dylib 0x000000010f3b733d _dispatch_client_callout 8
28 libdispatch.dylib 0x000000010f3bc9f3 _dispatch_block_invoke_direct 592
29 FrontBoardServices 0x000000011018d498 FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK 24
30 FrontBoardServices 0x000000011018d14e - [FBSSerialQueue _performNext] 464
31 FrontBoardServices 0x000000011018d6bd - [FBSSerialQueue _performNextFromRunLoopSource] 45
32 CoreFoundation 0x000000010b9ae101 CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION 17
33 CoreFoundation 0x000000010ba4df71 __CFRunLoopDoSource0 81
34 CoreFoundation 0x000000010b992a19 __CFRunLoopDoSources0 185
35 CoreFoundation 0x000000010b991fff __CFRunLoopRun 1279
36 CoreFoundation 0x000000010b991889 CFRunLoopRunSpecific 409
37 GraphicsServices 0x0000000110a219c6 GSEventRunModal 62
38 UIKit 0x000000010be895d6 UIApplicationMain 159
39 UITextView 0x000000010a7914df main 111
40 libdyld.dylib 0x000000010f433d81 start 1
41 ??? 0x0000000000000001 0x0 1
）
libc abi.dylib：以NSException类型的未捕获异常终止
1 回答
问题是因为您使用
NSMutableString初始化NSMutableAttributedString然后更改其属性 .代码允许您初始化变量但
NSMutableString不允许您添加属性，因此它崩溃..代码应该是这样的..（将分配类更改为 NSMutableAttributedString ）
谢谢 .