iOS 错误锦集

   从今天开始，我打算把自己所有遇到的错误，无论大大小小，都保存下来，以供自己反思，少点粗心才能提高效率

1、
This application is modifying the autolayout engine from a background thread after the engine was accessed from the main thread. This can lead to engine corruption and weird crashes.

2017-12-20 21:29:03.954058+0800 SwiftLive[3749:2123191] This application is modifying the autolayout engine from a background thread after the engine was accessed from the main thread. This can lead to engine corruption and weird crashes. Stack:(0   CoreFoundation                      0x000000018cbbaff8 <redacted> + 1481   libobjc.A.dylib                     0x000000018b61c538 objc_exception_throw + 562   CoreFoundation                      0x000000018cbbaf28 <redacted> + 03   Foundation                          0x000000018d7ad378 <redacted> + 1284   Foundation                          0x000000018d7ad0f8 <redacted> + 765   Foundation                          0x000000018d5f9b48 <redacted> + 1326   Foundation                          0x000000018d7abd80 <redacted> + 1127   UIKit                               0x0000000192ce9eac <redacted> + 16928   QuartzCore                          0x000000018feda274 <redacted> + 1489   UIKit                               0x000000019333a234 <redacted> + 6410  QuartzCore                          0x000000018fecede8 <redacted> + 29211  QuartzCore                          0x000000018fececa8 <redacted> + 3212  QuartzCore                          0x000000018fe4a34c <redacted> + 25213  QuartzCore                          0x000000018fe713ac <redacted> + 50414  QuartzCore                          0x000000018fe716d8 <redacted> + 24415  libsystem_pthread.dylib             0x000000018bc7be20 <redacted> + 57216  libsystem_pthread.dylib             0x000000018bc7bb48 <redacted> + 20017  libsystem_pthread.dylib             0x000000018bc7b1d8 _pthread_wqthread + 131218  libsystem_pthread.dylib             0x000000018bc7acac start_wqthread + 4)

从上面的报错信息可以看出，线程在运行的时候子线程修改了主线程UI的布局约束，在iOS开发中，所有的有关界面UI的更新操作必须要在主线程中完成。

在需要的时候，加上下面这句吧：

        dispatch_async(dispatch_get_main_queue(), ^{             //inset code....   
        });

2、
attempting to add unsupported attribute: (null)

2017-12-22 16:31:25.357 SwiftLive[3878:2402908] <Unknown>: [BLYLog]  Trapped uncaught exception 'NSInternalInconsistencyException', reason: 'attempting to add unsupported attribute: (null)' (0   CoreFoundation                      0x000000018cbbaff8 <redacted> + 1481   libobjc.A.dylib                     0x000000018b61c538 objc_exception_throw + 562   CoreFoundation                      0x000000018cbbaeb4 <redacted> + 03   Foundation                          0x000000018d653760 <redacted> + 1124   SwiftLive                           0x00000001007c47d0 -[MASViewConstraint setSecondViewAttribute:] + 7725   SwiftLive                           0x00000001007c5730 __40-[MASViewConstraint equalToWithRelation]_block_invoke + 17566   SwiftLive                           0x00000001007be424 __24-[MASConstraint equalTo]_block_invoke + 1007   SwiftLive                           0x000000010017741c __29-[FLGiftSendView configureUI]_block_invoke.66 + 5168   SwiftLive                           0x00000001007cbfd8 -[UIView(MASAdditions) mas_makeConstraints:] + 1329   SwiftLive                           0x0000000100175b7c -[FLGiftSendView configureUI] + 75210  SwiftLive                           0x00000001001757c4 -[FLGiftSendView initWithFrame:] + 33211  SwiftLive                           0x000000010045eb2c -[FLChooseGiftsView setupUI] + 368012  SwiftLive                           0x000000010045dbb4 -[FLChooseGiftsView init] + 13613  SwiftLive                           0x0000000100291570 -[FLLiveMainInterfaceViewController setupContentView] + 468014  SwiftLive                           0x000000010028f3bc -[FLLiveMainInterfaceViewController setupUI] + 270815  SwiftLive                           0x00000001002881e0 -[FLLiveMainInterfaceViewController viewDidLoad] + 34416  UIKit                               0x0000000192cecb04 <redacted> + 103617  UIKit                               0x0000000192d04590 <redacted> + 13218  UIKit                               0x0000000192e88e18 <redacted> + 114419  UIKit                               0x0000000192da37bc <redacted> + 67620  UIKit                               0x0000000192da3424 <redacted> + 6421  UIKit                               0x0000000192da3388 <redacted> + 18822  UIKit                               0x0000000192ce9cc0 <redacted> + 120023  QuartzCore                          0x000000018feda274 <redacted> + 14824  QuartzCore                          0x000000018fecede8 <redacted> + 29225  QuartzCore                          0x000000018fececa8 <redacted> + 3226  QuartzCore                          0x000000018fe4a34c <redacted> + 25227  QuartzCore                          0x000000018fe713ac <redacted> + 50428  QuartzCore                          0x000000018fe71e78 <redacted> + 12029  CoreFoundation                      0x000000018cb689a8 <redacted> + 3230  CoreFoundation                      0x000000018cb66630 <redacted> + 37231  CoreFoundation                      0x000000018cb66a7c <redacted> + 95632  CoreFoundation                      0x000000018ca96da4 CFRunLoopRunSpecific + 42433  GraphicsServices                    0x000000018e501074 GSEventRunModal + 10034  UIKit                               0x0000000192d51c9c UIApplicationMain + 20835  SwiftLive                           0x0000000100437dd8 main + 31236  libdyld.dylib                       0x000000018baa559c <redacted> + 4)

从上面的报错信息，没有什么意外,就是上一个控件布局有问题,或者是布局的顺序有问题，也有可能是约束冲突，或者约束不全。

       使用Masonry要注意约束的完整性。否则就会出现上述报错。

3、今天很坑的一个事情，我想写一个不固定高度的View，View里面放一些控件,我还要给View描边，整个布局布局好以后，发现View里面的控件没有出来,然后我各种看小面包，左边显示控件是存在的，右边的界面却和真机一样没有出来，苦了我又是设置背景颜色调试，又是各种检查布局的，下面是我布局的代码：

    约束检查了一遍又一遍，还是没有任何思路，这里要感谢师父一直给我提示，给我一些调试的方法，我就感觉，应该还是布局的问题，于是我改了如下代码：

    我将 

 make.height.mas_lessThanOrEqualTo(33 * ScreenHeightRatio);

这句代码改成了

make.height.mas_equalTo(33 * ScreenHeightRatio);

结果就可以了，说明用masorny布局，不确定高度的View，是不可以描边等操作的，会出现一系列的问题，可怜我太菜，这个问题调试了很久

4、关于IOS开发之关于UIButton点击没有响应问题

       在做UI界面的时候，确认butten 是最后添加的呀，但是，怎么就不响应点击方法呢？小面包查了一遍又一遍，真的是粗心误大事，

        感谢在网上找到的资料，保存一下：

1、如果一个UIButton的frame超出父视图的frame，UIButton还是可以显现的，但响应不了点击事件了，当开发中，遇到UIButton点击没有响应问题时，我们需要输出btn及它父视图的frame，看看btn.frame是否超出view

2、还可以通过Debug--->View Debugging--->show ViewFrames查看按钮上层是否有透明视图。

我的是第一种：UIButten控件大小超出了父控件的大小，所以响应不了点击事件了。

5、-[__NSCFDictionary length]: unrecognized selector sent to instance 0x171c60980' 

     出错在类型上面，我定义的是nsnumber类型，而拿到的是后天返回的是nsstring类型，直接赋值了，小白果然效率低，哎。。。。。。。。。。

    

2017-12-23 19:29:41.451 SwiftLive[4057:2610494] <Unknown>: [BLYLog]  Trapped uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFDictionary length]: unrecognized selector sent to instance 0x171c60980' (0   CoreFoundation                      0x000000018cbbaff8 <redacted> + 1481   libobjc.A.dylib                     0x000000018b61c538 objc_exception_throw + 562   CoreFoundation                      0x000000018cbc1ef4 <redacted> + 03   CoreFoundation                      0x000000018cbbef54 <redacted> + 9164   CoreFoundation                      0x000000018cabad4c _CF_forwarding_prep_0 + 925   UIKit                               0x0000000192cf66c8 <redacted> + 3126   SwiftLive                           0x000000010014f574 -[FLGiftSendView tableView:didSelectRowAtIndexPath:] + 9007   UIKit                               0x0000000192e17a9c <redacted> + 12008   UIKit                               0x0000000192ec7820 <redacted> + 2689   UIKit                               0x0000000192f79594 <redacted> + 29210  UIKit                               0x0000000192f6b630 <redacted> + 52811  UIKit                               0x0000000192cdf28c <redacted> + 13212  CoreFoundation                      0x000000018cb689a8 <redacted> + 3213  CoreFoundation                      0x000000018cb66630 <redacted> + 37214  CoreFoundation                      0x000000018cb66a7c <redacted> + 95615  CoreFoundation                      0x000000018ca96da4 CFRunLoopRunSpecific + 42416  GraphicsServices                    0x000000018e501074 GSEventRunModal + 10017  UIKit                               0x0000000192d51c9c UIApplicationMain + 20818  SwiftLive                           0x000000010040ba24 main + 31219  libdyld.dylib                       0x000000018baa559c <redacted> + 4)

解决：NSString 转 NSNumber ：

lastSeletNum = @([self.comeShowArray[indexPath.row][@"gift_num"] integerValue]);

6、不能同时比较：

我将一个string类型的字符串转换成int 类型，然后对齐比较大小，结果报了如下警告：

Comparison of constant 10 with boolean expression is always true

呼呼，不开森，iOS不能同时比较耶，要用&& 链接去比较

错误的代码如下：

    if (1 <= [listModle.liver_grade integerValue] <= 10) {        self.popularityImg.image = [UIImage imageNamed:@"icon_little_anchorlevel1_10"];    }else if (11 <= [listModle.liver_grade integerValue] <= 20){        self.popularityImg.image = [UIImage imageNamed:@"icon_little_anchorlevel11_20"];    }else if (21 <= [listModle.liver_grade integerValue] <= 30){        self.popularityImg.image = [UIImage imageNamed:@"icon_little_anchorlevel21_30"];    }else if (31 <= [listModle.liver_grade integerValue] <= 40){        self.popularityImg.image = [UIImage imageNamed:@"icon_little_anchorlevel31_40"];    }else if (41 <= [listModle.liver_grade integerValue] <= 50){        self.popularityImg.image = [UIImage imageNamed:@"icon_little_anchorlevel41_50"];    }

正确的代码如下：

NSInteger grade = [listModle.liver_grade integerValue];    if (1 <= grade  && grade <= 10) {        self.popularityImg.image = [UIImage imageNamed:@"icon_little_anchorlevel1_10"];    }else if (11 <= grade && grade <= 20){        self.popularityImg.image = [UIImage imageNamed:@"icon_little_anchorlevel11_20"];    }else if (21 <= grade && grade <= 30){        self.popularityImg.image = [UIImage imageNamed:@"icon_little_anchorlevel21_30"];    }else if (31 <= grade && grade <= 40){        self.popularityImg.image = [UIImage imageNamed:@"icon_little_anchorlevel31_40"];    }else if (41 <= grade && grade <= 50){        self.popularityImg.image = [UIImage imageNamed:@"icon_little_anchorlevel41_50"];    }