ios - 简单的录音应用程序 "uncaught NSException"

Question

我正在尝试为 iPhone 构建这个小项目，但是当我将其部署到 iOS 模拟器上时，我收到错误“libc++abi.dylib:因未捕获的 NSException 类型异常而终止”。

代码非常简单，如下:

WHGViewController.h:

#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>

@interface WHGViewController : UIViewController <AVAudioRecorderDelegate, AVAudioPlayerDelegate>

@property (strong, nonatomic) AVAudioRecorder* rec;
@property (strong, nonatomic) AVAudioPlayer* ply;
@property (strong, nonatomic) IBOutlet UIButton *recBtn;
@property (strong, nonatomic) IBOutlet UIButton *plyBtn;
@property (strong, nonatomic) IBOutlet UIButton *stopBtn;

- (IBAction)recordAudio:(id)sender;
- (IBAction)playAudio:(id)sender;
- (IBAction)stop:(id)sender;

@end

WHGViewController.m:

#import "WHGViewController.h"

@interface WHGViewController ()

@end

@implementation WHGViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    _plyBtn.enabled = NO;
    _stopBtn.enabled = NO;

    NSArray *dirPaths;
    NSString *docsDir;

    dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES);
    docsDir = dirPaths[0];

    NSString *soundFilePath = [docsDir stringByAppendingPathComponent:@"test.caf"];

    NSURL *soundFileURL = [NSURL fileURLWithPath:soundFilePath];

    NSDictionary *recordSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                                    [NSNumber numberWithInt:AVAudioQualityMin],
                                    AVEncoderAudioQualityKey,
                                    [NSNumber numberWithInt:16],
                                    AVEncoderBitRateKey,
                                    [NSNumber numberWithInt:2],
                                    AVNumberOfChannelsKey,
                                    [NSNumber numberWithFloat:44100.0],
                                    AVSampleRateKey,
                                    nil];

    NSError *error = nil;
    _rec = [[AVAudioRecorder alloc] initWithURL:soundFileURL settings:recordSettings error:&error];

    if(error){
        NSLog(@"error: %@", [error localizedDescription]);
    } else {
        [_rec prepareToRecord];
    }
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
}

- (IBAction)recordAudio:(id)sender {
    _plyBtn.enabled = NO;
    _stopBtn.enabled = YES;
    [_rec record];
}

- (IBAction)playAudio:(id)sender {
    if(!_rec.recording){
        _recBtn.enabled = NO;
        _stopBtn.enabled = YES;

        NSError *error;

        _ply = [[AVAudioPlayer alloc] initWithContentsOfURL:_rec.url error:&error];

        _ply.delegate = self;

        if(error){
            NSLog(@"error: %@", [error localizedDescription]);
        } else {
            [_ply play];
        }
    }
}

- (IBAction)stop:(id)sender {

    _stopBtn.enabled = NO;
    _recBtn.enabled = YES;
    _plyBtn.enabled = YES;

    if(_rec.recording) {
        [_rec stop];
    } else if(_ply.playing) {
        [_ply stop];
    }
}

- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag {
    _recBtn.enabled = YES;
}

- (void)audioPlayerDecodeErrorDidOccur:(AVAudioPlayer *)player error:(NSError *)error {
    NSLog(@"Decode error did occur");
}

- (void)audioRecorderDidFinishRecording:(AVAudioRecorder *)recorder successfully:(BOOL)flag {

}

- (void)audioRecorderEncodeErrorDidOccur:(AVAudioRecorder *)recorder error:(NSError *)error {
    NSLog(@"Encode error did occur");
}

@end

这是完整的崩溃报告:

2013-11-15 23:51:08.814 WhisperClient[51402:70b] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<WHGViewController 0x9564950> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key playAudio.'
*** First throw call stack:
(
    0   CoreFoundation                      0x019665e4 __exceptionPreprocess + 180
    1   libobjc.A.dylib                     0x016e98b6 objc_exception_throw + 44
    2   CoreFoundation                      0x019f66a1 -[NSException raise] + 17
    3   Foundation                          0x013aa9ee -[NSObject(NSKeyValueCoding) setValue:forUndefinedKey:] + 282
    4   Foundation                          0x01316cfb _NSSetUsingKeyValueSetter + 88
    5   Foundation                          0x01316253 -[NSObject(NSKeyValueCoding) setValue:forKey:] + 267
    6   Foundation                          0x0137870a -[NSObject(NSKeyValueCoding) setValue:forKeyPath:] + 412
    7   UIKit                               0x006f9a15 -[UIRuntimeOutletConnection connect] + 106
    8   libobjc.A.dylib                     0x016fb7d2 -[NSObject performSelector:] + 62
    9   CoreFoundation                      0x01961b6a -[NSArray makeObjectsPerformSelector:] + 314
    10  UIKit                               0x006f856e -[UINib instantiateWithOwner:options:] + 1417
    11  UIKit                               0x0056a605 -[UIViewController _loadViewFromNibNamed:bundle:] + 280
    12  UIKit                               0x0056adad -[UIViewController loadView] + 302
    13  UIKit                               0x0056b0ae -[UIViewController loadViewIfRequired] + 78
    14  UIKit                               0x0056b5b4 -[UIViewController view] + 35
    15  UIKit                               0x004939fd -[UIWindow addRootViewControllerViewIfPossible] + 66
    16  UIKit                               0x00493d97 -[UIWindow _setHidden:forced:] + 312
    17  UIKit                               0x0049402d -[UIWindow _orderFrontWithoutMakingKey] + 49
    18  UIKit                               0x0049e89a -[UIWindow makeKeyAndVisible] + 65
    19  UIKit                               0x00451cd0 -[UIApplication _callInitializationDelegatesForURL:payload:suspended:] + 1851
    20  UIKit                               0x004563a8 -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:] + 824
    21  UIKit                               0x0046a87c -[UIApplication handleEvent:withNewEvent:] + 3447
    22  UIKit                               0x0046ade9 -[UIApplication sendEvent:] + 85
    23  UIKit                               0x00458025 _UIApplicationHandleEvent + 736
    24  GraphicsServices                    0x02f192f6 _PurpleEventCallback + 776
    25  GraphicsServices                    0x02f18e01 PurpleEventCallback + 46
    26  CoreFoundation                      0x018e1d65 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 53
    27  CoreFoundation                      0x018e1a9b __CFRunLoopDoSource1 + 523
    28  CoreFoundation                      0x0190c77c __CFRunLoopRun + 2156
    29  CoreFoundation                      0x0190bac3 CFRunLoopRunSpecific + 467
    30  CoreFoundation                      0x0190b8db CFRunLoopRunInMode + 123
    31  UIKit                               0x00455add -[UIApplication _run] + 840
    32  UIKit                               0x00457d3b UIApplicationMain + 1225
    33  WhisperClient                       0x0000363d main + 141
    34  libdyld.dylib                       0x03afb70d start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

如果有人能告诉我为什么我会遇到未捕获的异常，或者更好的是，我在哪里得到它，我将非常感激。提前致谢!

Answer 1

这意味着您的 storyboard 或 xib 文件中的 IBActions 或 IBOutlets 之一不正确挂上了。它的名称是 playAudio，它位于名为 WHGViewController 的 View Controller 内部:

2013-11-15 23:51:08.814 WhisperClient[51402:70b] 
***
  Terminating app due to uncaught exception 'NSUnknownKeyException',
  //Here it says that the error is in WHGViewController
  reason: '[<WHGViewController 0x9564950> setValue:forUndefinedKey:]:
      //Here it says that the IBAction/IBOutlet is named playAudio
      this class is not key value coding-compliant for the key playAudio.'
***

只需进入 View Controller ，然后检查所有 socket 和操作所连接的内容。如果您看到黄色三角形，则意味着该值未定义，您必须从 View Controller 中将其删除。

playAudio 未定义，但 WHGViewController 正在尝试使用它，因此当它到达调用 playAudio 的位置时，它找不到它，因此您的应用程序就会崩溃。