在Unity3d上调用Android摄像头参数后，Android Camera Preview无法启动

Question

我在从android.hardware.camera.getparameters获取浮动参数后尝试启动相机并将其放在GUI.Button上，但是当我在Android上运行应用程序时，我得到一个黑屏。在黑屏上GUI.button或相机预览。但不是GUI.button取决于我先调用浮点数还是相机。  有人知道问题出在哪里吗？我是初学者，我不知道在哪里可以找到问题。

这是我的代码：

using UnityEngine;
using System.Collections;

public class Cam : MonoBehaviour {

    //variables privadas
    public static WebCamDevice[] devices = WebCamTexture.devices;
    private static float VerticalViewAngle;
    private float mi;

    //variables publicas



    void Awake () {
        //mi = hva ();
        Playcam ();
    }

    // Use this for initialization
    void Start () {

    }

    // Update is called once per frame
    void Update () {
        GUI.Button(new Rect(0,0,Screen.width,20),mi.ToString("F4"));
    }

    void OnGUI () {

    }
    // funciones

    public static Texture Startcamera(){

        //WebCamDevice cam = WebCamDevice();
        WebCamDevice cam = devices [0];
        WebCamTexture webCameraTexture  =    new WebCamTexture(cam.name);
        webCameraTexture.deviceName  = cam.name;
        webCameraTexture.Play();
        return webCameraTexture;

    }
    //gnereacion de variables
    public static float hva ()
    {

        AndroidJavaClass cameraClass = new AndroidJavaClass ("android.hardware.Camera");
        int camID = 0;
        AndroidJavaObject camera = cameraClass.CallStatic<AndroidJavaObject> ("open", camID);

        AndroidJavaObject cameraParameters = camera.Call<AndroidJavaObject> ("getParameters");
        VerticalViewAngle = cameraParameters.Call<float>("getFocalLength");
        //Debug.Log ("miguel                     "+ VerticalViewAngle);
        //Debug.Log ("fernando                     "+ VerticalViewAngle);
        return VerticalViewAngle;

    }

     public void  Playcam () {
        GUITexture BackgroundTexture = gameObject.AddComponent<GUITexture>();
           BackgroundTexture.pixelInset = new Rect(0,0,Screen.width,Screen.height);
        BackgroundTexture.texture = Startcamera ();
    }
}

这是我的androidmanifest.xml：

<?xml version="1.0" encoding="utf-8"?>
<manifest
    xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.unity3d.player"
	android:installLocation="preferExternal"
	android:theme="@android:style/Theme.NoTitleBar"
    android:versionCode="1"
    android:versionName="1.0">
        <supports-screens
        android:smallScreens="true"
        android:normalScreens="true"
        android:largeScreens="true"
        android:xlargeScreens="true"
        android:anyDensity="true"/>
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.CAMERA" />
     <uses-feature android:name="android.hardware.camera" />
	 <uses-feature android:name="android.hardware.camera.autofocus" />
	 <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    
    <application
        android:icon="@drawable/app_icon"
        android:label="@string/app_name"
        android:theme="@android:style/Theme.NoTitleBar.Fullscreen"
        android:debuggable="false">
        <activity android:name="com.unity3d.player.UnityPlayerNativeActivity"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
            <meta-data android:name="unityplayer.UnityActivity" android:value="true" />
            <meta-data android:name="unityplayer.ForwardNativeEventsToDalvik" android:value="false" />
        </activity>
        <activity android:name="com.unity3d.player.VideoPlayer"
                  android:label="@string/app_name"
                  android:screenOrientation="portrait"
                  android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen">
        </activity>
        <!--
            To support devices using the TI S3D library for stereo mode we must 
            add the following library.
            Devices that require this are: ODG X6 
        -->
        <uses-library android:name="com.ti.s3d" android:required="false" />
        <!--
            To support the ODG R7 in stereo mode we must add the following library.
        -->
        <uses-library android:name="com.osterhoutgroup.api.ext" android:required="false" />
    </application>
</manifest>

<!-- android:installLocation="preferExternal" -->