Bug 14307 - AVAudioPlayer.FromUrl fails but returns an null error
Summary: AVAudioPlayer.FromUrl fails but returns an null error
Alias: None
Product: iOS
Classification: Xamarin
Component: Xamarin.iOS.dll ()
Version: 6.4.4
Hardware: Macintosh All
: --- normal
Target Milestone: Untriaged
Assignee: Larry O'Brien
Depends on:
Reported: 2013-08-28 23:11 UTC by pierre
Modified: 2017-05-26 23:37 UTC (History)
2 users (show)

Is this bug a regression?: ---
Last known good build:

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Description pierre 2013-08-28 23:11:14 UTC
The following code fails (audioPlayer == null) but returns an null error (loadError == null).

NSError loadError;
audioPlayer = AVAudioPlayer.FromUrl(new NSUrl(validParthToTheMusic), out loadError);

After having looked carefully to the sample I found the problem. By adding 'false' to the second argument of NSUrl constructor it works properly (audioPlayer  == null and loadError != null or audioPlayer != null and loadError == null).

NSError loadError;
audioPlayer = AVAudioPlayer.FromUrl(new NSUrl(validParthToTheMusic, false), out loadError);
Comment 1 Sebastien Pouliot 2013-08-29 09:39:59 UTC
Can you give us an example of the value for `validParthToTheMusic` ?

And where's the file it load is actually located ?
Comment 2 pierre 2013-08-29 21:21:10 UTC
Sorry for the lack of precision, after a check the bug seems to happen only on the iPhoneSimulator.

My file is loaded as Content.
Here is an example of path:

/Users/pierre/Library/Application Support/iPhone Simulator/6.1/Applications/16A89A50-94EE-4CAF-A4EF-B56B8DD54ED7/AudioTestsiOS.app/app_data/assets/audio/ae.wav"
Comment 3 Sebastien Pouliot 2013-09-03 10:30:07 UTC
My guess* is that your `NSUrl` instance is invalid, i.e. it's handle property is 0x0 (IntPtr.Zero). E.g.

   string file = Path.Combine (NSBundle.MainBundle.ResourcePath, "Hand.wav");



on iOS devices, while it returns:

"/Users/poupou/Library/Application Support/iPhone Simulator/6.1/Applications/81F5B81E-B279-416D-BB63-671FB8B407FF/monotouchtest.app/Hand.wav"

on the iOS simulator.

The first one can be used with `initWithString:` (native), which is `NSUrl(string)` while the second can not.

Using `NSUrl(string,bool)` calls `initFileURLWithPath:isDirectory:` which works in both case (note the difference between initWith*String* and init*WithPath*).

So what this means it that you're effectively calling `initWithContentsOfURL:error:` (AVAudioPlayer.FromUrl) with a null `NSUrl` which is not allowed (and undefined). Sadly it looks like the native returns `nil` without setting the `NSError` parameter to anything useful.

* I can duplicate something like this (even if I can't be sure it's 100% identical to yours).

c.c. Larry for updating documentation (based on above). Note that [1] is currently bad.

[1] http://api.xamarin.com/?link=C%3aMonoTouch.Foundation.NSUrl.NSUrl(string%2cbool)
Comment 4 Sebastien Pouliot 2013-09-03 10:57:08 UTC
Note that `Class.ThrowOnInitFailure` which should check for `Handle == IntPtr.Zero`, does not work in this case. I filled bug #14399 about it.
Comment 5 Larry O'Brien 2017-05-26 23:37:54 UTC
Documentation updated in 5a5880ae920dfac98d58fb6f5246de912165bdd7