AVAudioRecorder不会在设备上录制

Question

This is my method:

-(void) playOrRecord:(UIButton *)sender {
    if (playBool == YES) {
        NSError *error = nil;
        NSString *filePath = [[NSBundle mainBundle] pathForResource:[NSString stringWithFormat: @"%d", [sender tag]] ofType:@"caf"];
        NSURL *fileUrl = [NSURL fileURLWithPath:filePath];
        AVAudioPlayer *player = [[AVAudioPlayer alloc] initWithContentsOfURL:fileUrl error:&error];
        [player setNumberOfLoops:0];
        [player play];      
    }
    else if (playBool == NO) {
        if ([recorder isRecording]) {
            [recorder stop];
            [nowRecording setImage:[UIImage imageNamed:@"NormalNormal.png"] forState:UIControlStateNormal];
            [nowRecording setImage:[UIImage imageNamed:@"NormalSelected.png"] forState:UIControlStateSelected];
        }
        if (nowRecording == sender) {
        nowRecording = nil;
        return;
        }
        nowRecording = sender;
        NSError *error = nil;
        NSString *filePath = [[NSBundle mainBundle] pathForResource:[NSString stringWithFormat: @"%d", [sender tag]] ofType:@"caf"];
        NSURL *fileUrl = [NSURL fileURLWithPath:filePath];
        [sender setImage:[UIImage imageNamed:@"RecordingNormal.png"] forState:UIControlStateNormal];
        [sender setImage:[UIImage imageNamed:@"RecordingSelected.png"] forState:UIControlStateSelected];        
        recorder = [[AVAudioRecorder alloc] initWithURL:fileUrl settings:recordSettings error:&error];
        [recorder record];
    }
}

Most of it is self explanatory; playBool is a BOOL that is YES when it is in play mode. Everything works in the simulator however, when I run it on a device, [recorder record] returns NO. Does anyone have a clue as to why this is happening?

Answer 1

If anywhere in your code you have this setup:

[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];

Change it to:

[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];

Setting the wrong AVAudioSession category will cause record/play to fail.

Answer 2

This is because you cannot modify the app-bundle on the device ( it is signed ). You can record to either the docs folder for your app, or the tmp directory.

Answer 3

Ok, solved my own question; I don't know why, but I have to record to the NSTemporaryDirectory when on a device. Changing that completely fixed it.

Answer 4

此外，请确保您的应用程序可以访问麦克风（即在iOS设置中，向下滚动并找到您的应用程序，它应该有'麦克风'，您需要切换到'打开'）

Answer 5

I had the exact same problem. It turns out I was bumping up against an incorrectly generated path statement. The AVAudioRecorder initialized fine - and without incident - but iOS simply would not allow me to write to it. Why? Check it out:

    /* The following code will fail - why? It fails because it is trying to write some path that is NOT accessible by
    this app.
NSString *recordedAudioPath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) 
                                objectAtIndex:0] 
                               stringByAppendingString:@"recorded.caf"];
 */
// Correction:
NSString *recordedAudioPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) 
                               objectAtIndex:0];

recordedAudioPath = [recordedAudioPath stringByAppendingPathComponent:@"recorded.caf"];
NSURL *recordURL = [NSURL fileURLWithPath:recordedAudioPath];

This makes complete sense now. Thanks for steering me in the right direction.