C# AVAudioRecorder始终为空

我一直在尝试以xamarin的形式录制音频，但没有直接的方法，所以我尝试通过自定义渲染来实现它，并遵循了中的示例

//AVAudioRecorder创建

        //set up the NSObject Array of values that will be combined with the keys to make the NSDictionary
        NSObject[] values = new NSObject[]
        {
            NSNumber.FromFloat (16000.0f), //Sample Rate
            NSNumber.FromInt32 ((int)AudioToolbox.AudioFormatType.MPEG4AAC), //AVFormat
            NSNumber.FromInt32 (1), //Channels
            NSNumber.FromInt32 (16), //PCMBitDepth  
            NSNumber.FromBoolean (false), //IsBigEndianKey
            NSNumber.FromBoolean (false) //IsFloatKey
        };

        //Set up the NSObject Array of keys that will be combined with the values to make the NSDictionary
        NSObject[] keys = new NSObject[]
        {
            AVAudioSettings.AVSampleRateKey,
            AVAudioSettings.AVFormatIDKey,
            AVAudioSettings.AVNumberOfChannelsKey,
            AVAudioSettings.AVLinearPCMBitDepthKey,
            AVAudioSettings.AVLinearPCMIsBigEndianKey,
            AVAudioSettings.AVLinearPCMIsFloatKey
        };

        //Set Settings with the Values and Keys to create the NSDictionary
        settings = NSDictionary.FromObjectsAndKeys (values, keys);

        //Set recorder parameters
        recorder = AVAudioRecorder.Create(url, new AudioSettings(settings), out error);

但是在代码中，“recorder=AVAudioRecorder.Create（url、新音频设置（设置）、out错误）；”始终为空

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任何帮助都将不胜感激。

我自己修复了它，通过如下更改音频设置使其正常工作

    `var settings = new AudioSettings
        {
            SampleRate = 44100.0f,
            Format = AudioFormatType.LinearPCM,
            NumberChannels = 1,
            LinearPcmBitDepth = 16,
            AudioQuality = AVAudioQuality.High,
        };`

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错误是什么？System.NullReferenceException，bcuz recorder为null@BugFinder这不是原因。。错误是告诉您它失败了。“音频设置”功能中有什么？