问题
I have searched a lot trying to figure this out - the code to me seems ok but the functionality doesn't reflect this.
I have a View that is presented (its an Audio Recorder view). You can press record and it records to a file just fine (data exists in the file). I can then play the file back via the play button (the AVAudioPlayer is pointing to that file).
However when I close/dismiss that view and come back to it - the file will not play when Play is tapped even though it should be exactly the same code as the file location has not changed.
UPDATE:
Seems that [audioPlayer play] returns no. I have also looked into the data. It seems that when the view appears again and loads that data it doesnt load it correctly (NSdata in Nslog displays mainly 0's) - even though the file exists and has data in it (i can see and hear it after transferring to my mac).
This leads me to suspect that either I am loading the data wrong or avaudioplayer wont read the data for some reason...
Please take a look at the code below:
(NSString *) removeCharsFrom: (NSString *) remover {
remover = [remover stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
remover = [remover stringByReplacingOccurrencesOfString:@" " withString:@"_"];
remover = [remover stringByReplacingOccurrencesOfString:@"/" withString:@"_"];
remover = [remover stringByReplacingOccurrencesOfString:@"\\" withString:@"_"];
remover = [remover stringByReplacingOccurrencesOfString:@":" withString:@"_"];
remover = [remover stringByReplacingOccurrencesOfString:@";" withString:@"_"];
remover = [remover stringByReplacingOccurrencesOfString:@"(" withString:@"_"];
remover = [remover stringByReplacingOccurrencesOfString:@")" withString:@"_"];
remover = [remover stringByReplacingOccurrencesOfString:@"£" withString:@"_"];
remover = [remover stringByReplacingOccurrencesOfString:@"$" withString:@"_"];
remover = [remover stringByReplacingOccurrencesOfString:@"&" withString:@"_"];
remover = [remover stringByReplacingOccurrencesOfString:@"'" withString:@"_"];
remover = [remover stringByReplacingOccurrencesOfString:@"{" withString:@"_"];
remover = [remover stringByReplacingOccurrencesOfString:@"}" withString:@"_"];
remover = [remover stringByReplacingOccurrencesOfString:@"[" withString:@"_"];
remover = [remover stringByReplacingOccurrencesOfString:@"]" withString:@"_"];
remover = [remover stringByReplacingOccurrencesOfString:@"""" withString:@"_"];
return remover;
}
- (NSString *) audioPathForResource: (NSString *) audio {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *saveDirectory = [paths objectAtIndex:0];
NSString *newFolder = [saveDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"/%@/Audio",catName]];
if (![[NSFileManager defaultManager] fileExistsAtPath:newFolder]) {
[[NSFileManager defaultManager] createDirectoryAtPath:newFolder withIntermediateDirectories:YES attributes:nil error:nil];
}
NSString *saveFileName = [NSString stringWithFormat:@"%@.caf",audio];
NSString *newFilePath = [newFolder stringByAppendingPathComponent:saveFileName];
return [newFilePath stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
}
- (IBAction)cancelTapped:(id)sender {
[self dismissModalViewControllerAnimated:YES];
}
- (IBAction)saveTapped:(id)sender {
[self.parentViewController performSelector:@selector(changeAddAudioIcon)];
[self dismissModalViewControllerAnimated:YES];
}
- (IBAction)trashTapped:(id)sender {
UIAlertView *alert =
[[UIAlertView alloc] initWithTitle: @"Delete"
message: @"Would you like to delete the audio file? Warning: This cannot be undone."
delegate: self
cancelButtonTitle: @"Cancel"
otherButtonTitles: @"Delete", nil];
[alert show];
[alert release];
}
- (IBAction)pauseTapped:(id)sender {
pauseBtn.enabled = NO;
playBtn.enabled = YES;
recordBtn.enabled = YES;
trashBtn.enabled = YES;
if (audioRecorder.recording)
{
[audioRecorder stop];
} else if (audioPlayer.playing) {
[audioPlayer stop];
}
}
- (IBAction)recordTapped:(id)sender {
if (!audioRecorder.recording)
{
playBtn.enabled = NO;
pauseBtn.enabled = YES;
trashBtn.enabled = NO;
[audioRecorder record];
}
}
- (IBAction)playTapped:(id)sender {
pauseBtn.enabled = YES;
recordBtn.enabled = NO;
trashBtn.enabled = YES;
NSError *error;
NSLog(@"%@",filepathstring);
NSURL *soundFileURL = [NSURL fileURLWithPath:filepathstring];
audioPlayer = [[AVAudioPlayer alloc]
initWithContentsOfURL:soundFileURL
error:&error];
audioPlayer.delegate = self;
if (error)
NSLog(@"Error: %@",
[error localizedDescription]);
else
[audioPlayer play];
}
- (void)alertView: (UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex {
switch (buttonIndex) {
case 0:
return;
break;
case 1:
{
NSError *error = nil;
[[NSFileManager defaultManager] removeItemAtPath:filepathstring error:&error];
trashBtn.enabled = NO;
}
break;
default:
break;
}
}
-(void)audioPlayerDidFinishPlaying:
(AVAudioPlayer *)player successfully:(BOOL)flag
{
recordBtn.enabled = YES;
pauseBtn.enabled = NO;
playBtn.enabled = YES;
if(player != audioPlayer) {
[player release];
}
}
-(void)audioPlayerDecodeErrorDidOccur:
(AVAudioPlayer *)player
error:(NSError *)error
{
NSLog(@"Decode Error occurred");
}
-(void)audioRecorderDidFinishRecording:
(AVAudioRecorder *)recorder
successfully:(BOOL)flag
{
NSLog(@"Recording success:%@",flag ? @"YES" : @"NO");
trashBtn.enabled = YES;
pauseBtn.enabled = NO;
playBtn.enabled = YES;
}
-(void)audioRecorderEncodeErrorDidOccur:
(AVAudioRecorder *)recorder
error:(NSError *)error
{
NSLog(@"Encode Error occurred");
}
#pragma mark - View lifecycle
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
}
- (void) viewWillAppear:(BOOL)animated {
catName = [NSString stringWithFormat:@"%@",[self removeCharsFrom:catName]];
testName = [NSString stringWithFormat:@"%@",[self removeCharsFrom:testName]];
filepathstring = [[self audioPathForResource:testName] retain];
NSLog(@"At start = %@",filepathstring);
if ([[NSFileManager defaultManager] fileExistsAtPath:filepathstring]) {
playBtn.enabled = YES;
trashBtn.enabled = YES;
recordBtn.enabled = YES;
}
else
{
playBtn.enabled = NO;
trashBtn.enabled = NO;
}
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];
NSURL *soundFileURL = [NSURL fileURLWithPath:filepathstring];
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;
audioRecorder = [[AVAudioRecorder alloc]
initWithURL:soundFileURL
settings:recordSettings
error:&error];
audioRecorder.delegate = self;
if (error)
{
NSLog(@"error: %@", [error localizedDescription]);
} else {
[audioRecorder prepareToRecord];
}
}
- (void)viewDidUnload
{
[self setCancelBtn:nil];
[self setSaveBtn:nil];
[self setTimeLabel:nil];
[self setDescriptionLabel:nil];
[self setToolsBar:nil];
[self setTrashBtn:nil];
[self setPauseBtn:nil];
[self setRecordBtn:nil];
[self setPlayBtn:nil];
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
// Return YES for supported orientations
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
return YES;
} else {
return UIInterfaceOrientationIsPortrait(interfaceOrientation);
}
}
- (void)dealloc {
[cancelBtn release];
[saveBtn release];
[timeLabel release];
[descriptionLabel release];
[toolsBar release];
[trashBtn release];
[pauseBtn release];
[recordBtn release];
[playBtn release];
[audioPlayer release];
[audioRecorder release];
[super dealloc];
}
回答1:
Here is the answer:
NSData *data = [NSData dataWithContentsOfMappedFile:[NSString stringWithFormat:@"%@",filepathstring]];
AVAudioPlayer *ap = [[AVAudioPlayer alloc]
initWithData:data error:&error];
Seems that it just wouldnt work with filepathstring but within an NSString it worked fine. Obvious now!
来源：https://stackoverflow.com/questions/8898767/avaudioplayer-wont-play-existing-file-a-second-time