获取频率并显示视图控制器

Question

在我的应用程序中，我必须捕捉一个频率，然后显示视图控制器。要得到我使用的频率pitch detector。我得到的频率，但当我尝试运行应用程序，它应该加载视图控制器时崩溃。我后我写的代码：

- (void)frequencyChangedWithValue:(float)newFrequency { 
    frequencyRecived = newFrequency; 
    NSLog(@"%f", frequencyRecived); 
    if (frequencyRecived > 18000) { 
     [self.imageListening.layer removeAllAnimations]; 
     UIStoryboard *storyBoard = [UIStoryboard storyboardWithName:@"Main" bundle:nil]; 
     GameViewController *controller = (GameViewController*)[storyBoard instantiateViewControllerWithIdentifier:@"game"]; 
     [self stopListener]; 
     [self presentViewController:controller animated:YES completion:nil]; 
    } 
} 

它崩溃正是在[self presentViewController:controller animated:YES completion:nil];行和Xcode中这样说：

bool _WebTryThreadLock(bool), 0x14e5de30: Tried to obtain the web lock from a thread other than the main thread or the web thread. This may be a result of calling to UIKit from a secondary thread. Crashing now... 
1 0x366036fb WebThreadLock 
2 0x30e1e6a3 <redacted> 
3 0x30f46a69 <redacted> 
4 0x31015171 <redacted> 
5 0x31015111 <redacted> 
6 0x31014e87 <redacted> 
7 0x30e94a4f <redacted> 
8 0x31015171 <redacted> 
9 0x31014e87 <redacted> 
10 0x30f70607 <redacted> 
11 0x31015171 <redacted> 
12 0x31015111 <redacted> 
13 0x31014e87 <redacted> 
14 0x30f6fdd9 <redacted> 
15 0x30ec862b <redacted> 
16 0x30d24bed <redacted> 
17 0x30c0530d <redacted> 
18 0x30c05289 <redacted> 
19 0x30cae937 <redacted> 
20 0x30ceb4b3 <redacted> 
21 0x30ce9deb <redacted> 
22 0x30ce8e55 <redacted> 
23 0xcf783 -[ViewController frequencyChangedWithValue:] 
24 0xd11f7 RenderFFTCallback(void*, unsigned long*, AudioTimeStamp const*, unsigned long, unsigned long, AudioBufferList*) 
25 0x2dda569f <redacted> 
26 0x2dd944eb <redacted> 
27 0x2dd955d9 <redacted> 
28 0x2dd8bdff <redacted> 
29 0x2dcf9899 <redacted> 
30 0x2dd68889 <redacted> 
31 0x2dd94809 <redacted> 

我使用的代码在另一个应用程序和它的伟大工程，什么是错在我的代码，为什么它向我显示这个问题？我希望你能帮助我

Answer 1

frequencyChangedWithValue方法被调用在哪里？

错误表示您没有从主线程或webview线程调用它。你是否在后台线程中检测到音高？

你可以试试：

[self performSelectorOnMainThread:@selector(presentationWrapper:) withObject:nil waitUntilDone:YES]; 

，敷在本模式视图控制器：

- (void) presentationWrapper:(GameViewController *) controller { 
    [self presentViewController:controller animated:YES completion:nil]; 
} 

Answer 2

此代码不能在主线程中执行。尝试使用派发到主线程

- (void)frequencyChangedWithValue:(float)newFrequency { 
    frequencyRecived = newFrequency; 
    NSLog(@"%f", frequencyRecived); 
    if (frequencyRecived > 18000) { 
     [self stopListener]; 
     dispatch_async(dispatch_get_main_queue(), ^{ 
      [self.imageListening.layer removeAllAnimations]; 
      UIStoryboard *storyBoard = [UIStoryboard storyboardWithName:@"Main" bundle:nil]; 
      GameViewController *controller = (GameViewController*)[storyBoard instantiateViewControllerWithIdentifier:@"game"]; 
      [self presentViewController:controller animated:YES completion:nil]; 
     }); 
    } 
}