以下代码在调用start时抛出错误：

_recorder = new MediaRecorder();
                _recorder.SetAudioSource(AudioSource.Mic);
                _recorder.SetVideoSource(VideoSource.Camera);
                _recorder.SetProfile(CamcorderProfile.Get(CamcorderQuality.High));
                _recorder.SetOutputFile(FileName);
                _recorder.SetMaxDuration(10000);
                _recorder.Prepare();
                _recorder.Start();

错误消息似乎总是如下：

Java.Lang.RuntimeException: start failed.   
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <896ad1d315ca4ba7b117efb8dacaedcf>:0    
at Java.Interop.JniEnvironment+InstanceMethods.CallVoidMethod(Java.Interop.JniObjectReference instance, Java.Interop.JniMethodInfo method, Java.Interop.JniArgumentValue* args) [0x00069] in <25999cc1fde6426b852c2e027711c254>:0    
at Java.Interop.JniPeerMembers+JniInstanceMethods.InvokeVirtualVoidMethod(System.String encodedMember, Java.Interop.IJavaPeerable self, Java.Interop.JniArgumentValue* parameters) [0x0002a] in <25999cc1fde6426b852c2e027711c254>:0   
at Android.Media.MediaRecorder.Start () [0x0000a] in <7a2bbe1fcaec4467930361ae212aeea9>:0    
at MobileTwo.Droid.Services.AndroidCamera.InitializeCamera () [0x00120] in C:\GitRepositories\mobile-two\MobileTwo\MobileTwo.Droid\Services\AndroidCamera.cs:198
    --- End of managed Java.Lang.RuntimeException stack trace --- 
java.lang.RuntimeException: start failed.   
at android.media.MediaRecorder.start(Native Method)     
at md5b60ffeb829f638581ab2bb9b1a7f4f3f.InnerGestureListener.n_onSingleTapUp(Native Method)  
at md5b60ffeb829f638581ab2bb9b1a7f4f3f.InnerGestureListener.onSingleTapUp(InnerGestureListener.java:79)
at android.view.GestureDetector.onTouchEvent(GestureDetector.java:635)
at md5b60ffeb829f638581ab2bb9b1a7f4f3f.VisualElementRenderer_1.n_onTouch(Native Method)     
at md5b60ffeb829f638581ab2bb9b1a7f4f3f.VisualElementRenderer_1.onTouch(VisualElementRenderer_1.java:66)
at android.view.View.dispatchTouchEvent(View.java:9296)     
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2547)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2240)   
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2553)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2254)   
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2553)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2254)   
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2553)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2254)   
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2553)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2254)   
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2553)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2254)

在

android.view中的android.view.View.View.View.StartEvent（ViewGroup.java:2553）上的android.view.View.View.StartEvent（ViewGroup.java:2254）的android.view.ViewGroup.dispatchTransformedTouchEvent（ViewGroup.java:2553） . 位于android.view.View.View.StartEvent（ViewGroup.java:2553）的android.view.ViewGroup.DispatchTouchEvent（ViewGroup.java:2525）上的ViewGroup.dispatchTouchEvent（ViewGroup.java:2254），以及android.view.ViewGroup.dispatchTransformedTouchEvent（ViewGroup） .java：2553）在Android.view.View.View.St.Ev（ViewGroup.java:2254）的android.view.View.View.St.Ev上调整了android.view.View.St.EvatchTouchEvent（ViewGroup.java:2525）在Android.view上的android.view.View.View.View.View.St.Evatch上的android.view.View.View.View.St.Evatch上的android.view.View.View.St上的android.view.View.View.St上的android.view.View.View.St.EvatchTransformedTouchEvent（ViewGroup.java:2553）的android.view.View.View . ViewGroup.dispatchTouchEvent（ViewGroup.java:2254）在android.view.ViewGroup.dispatchTransformedTouchEvent（ViewGroup.java:2553）在android.view.ViewGroup.dispatchTouchEvent（ViewGroup.java:2254）在md5b60ffeb829f638581ab2bb9b1a7f4f3f.PlatformRenderer.n_dispatchTouchEvent（本机方法）在md5b60ffeb829f638581ab2bb9b1a7f4f3f.PlatformRenderer.dispatchTouchEvent（PlatformRenderer.java ：55）在Android.view.View.View.St上的android.view.View.View.St.EvatchTransformedTouchEvent（ViewGroup.java:2553）的android.view.View.View.StowsEispatchTransformedTouchEvent（ViewGroup.java:2553）位于android.view.ViewGroup的android.view.View.ViewGroup中的android.view.View.StartEvent（ViewGroup.java:2254）上的.view.ViewGroup.dispatchTouchEvent（ViewGroup.java:2254） . dispatchTransformedTouchEvent（ViewGroup.java:2553）位于android.view.View.View上的android.view.View.View.StartEvent（ViewGroup.java:2525）上的android.view.View.StartEvent（ViewGroup.java:2553） .ViewGroup.dispatchTouchEvent（ViewGroup.java:2254）位于com.android.internal.policy的android.view.ViewGroup.DispatchTouchEvent（ViewGroup.java:2553）的android.view.ViewGroup.dispatchTouchEvent（ViewGroup.java:2254） . PhoneWindow $ DecorView.superDispatchTouchEvent（PhoneWindow.java:2403）位于android.app.Activity.dispatchTouchEvent（Activity.java:2771）的android.upport的com.android.internal.policy.PhoneWindow.superDispatchTouchEvent（PhoneWindow.java:1737）位于com.android.internal.policy.PhoneWindow $ DecorView.dispatchTouchEvent（PhoneWindow）的android.support.v7.view.WindowCallbackWrapper.dispatchTouchEvent（WindowCallbackWrapper.java:60）中的.v7.view.WindowCallbackWrapper.dispatchTouchEvent（WindowCallbackWrapper.java:60） .java：2364）在android.view.ViewRootImpl上的android.view.View.dispatchPointerEvent（View.java:9520）$ ViewPostImeInputStage.processPointerEvent（ViewRootImpl.java:4230）at android.view.ViewRootImpl $ ViewPostImeInputStage.onProcess（ViewRootImpl . java：4096）在android.view.ViewRo otImpl $ InputStage.deliver（ViewRootImpl.java:3642）在android.view.ViewRootImpl $ InputStage.onDeliverToNext（ViewRootImpl.java:3695）android.view.ViewRootImpl $ InputStage.forward（ViewRootImpl.java:3661）at android.view .ViewRootImpl $ AsyncInputStage.forward（ViewRootImpl.java:3787）在android.view.ViewRootImpl $ InputStage.apply（ViewRootImpl.java:3669）的android.view.ViewRootImpl $ AsyncInputStage.apply（ViewRootImpl.java:3844）在android . 在android.view.ViewRootImpl $ InputStage.onDeliverToNext（ViewRootImpl.java:3695）的android.view.ViewRootImpl $ InputStage.forward（ViewRootImpl.java:3661）的android.ViewRootImpl $ InputStage.deliver（ViewRootImpl.java:3642） .view.ViewRootImpl $ InputStage.apply（ViewRootImpl.java:3669）位于Android的android.view.ViewRootImpl.deliverInputEvent（ViewRootImpl.java:5922）的android.view.ViewRootImpl $ InputStage.deliver（ViewRootImpl.java:3642） . view.ViewRootImpl.doProcessInputEvents（ViewRootImpl.java:5896）在android.view.ViewRootImpl.enqueueInputEvent（ViewRootImpl.java： 5857）在Android.os.MessageQueue.nativePollOnce（Native Method）的android.view.InputEventReceiver.dispatchInputEvent（InputEventReceiver.java:185）上的android.view.ViewRootImpl $ WindowInputEventReceiver.onInputEvent（ViewRootImpl.java:6025） .MessageQueue.next（MessageQueue.java:323）位于android.app.Looper.loop（Looper.java：135）的android.app.ActivityThread.main（ActivityThread.java:5417），位于java.lang.reflect.Method . 在Com.android.internal.os.ZygoteInit.main（ZygoteInit.java:616）的com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:726）中调用（Native Method）

我检查了一下，我有正确的清单权限 . 知道还有什么可能是错误的配置？ （我正在使用Nexus 7平板电脑进行调试）

编辑：这是我的清单

<uses-feature android:name="android.hardware.camera.front" /> 
<uses-feature android:name="android.hardware.microphone" /> 
<uses-feature android:name="android.hardware.camera" android:required="true" /> 
<uses-permission android:name="android.permission.CAMERA" /> 
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> 
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
android xamarin xamarin.android