Java 无法连接到摄像头服务，错误-2147483648

我想使用以下命令在Android手机上打开一个新的摄像头实例：

camera = Camera.open();

在我这么做之前，我会检查是否有带PacketManager的摄像头。我还在清单中添加了

权限.CAMERA

和功能

硬件.CAMERA

。如果我试图打开实例，我总是会得到一个

01-05 13:47:48.720: E/Camera(6555): Error -2147483648

有人能告诉我为什么会发生这种情况，以及我如何打开一个实例吗

    01-05 16:54:39.670: E/AndroidRuntime(9295): FATAL EXCEPTION: Thread-17341
    01-05 16:54:39.670: E/AndroidRuntime(9295): java.lang.RuntimeException: Fail to   connect to camera service
    01-05 16:54:39.670: E/AndroidRuntime(9295):     at    android.hardware.Camera.native_setup(Native Method)
    01-05 16:54:39.670: E/AndroidRuntime(9295):     at android.hardware.Camera.<init>(Camera.java:302)
    01-05 16:54:39.670: E/AndroidRuntime(9295):     at android.hardware.Camera.open(Camera.java:279)
    01-05 16:54:39.670: E/AndroidRuntime(9295):     at com.arcticcoding.nxtphone.MainActivity$GetCameraInstance.getCameraInstance(MainActivity.java:73)
    01-05 16:54:39.670: E/AndroidRuntime(9295):     at com.arcticcoding.nxtphone.MainActivity$GetCameraInstance.run(MainActivity.java:84)
    01-05 16:54:39.670: E/AndroidRuntime(9295):     at java.lang.Thread.run(Thread.java:856)

显示

。。。
...

为确保安全，请添加您的清单（权限部分）

    private Camera getCameraInstance() {
    Camera camera = null;
    try {
        Log.d(TAG, "Opening camera instance");
        camera = Camera.open();
    } catch(Exception e) {
        Log.d(TAG, "Error while opening camera");
        e.printStackTrace();
    }
    return camera;
}

    ...
    <uses-permission android:name="android.permission.CAMERA"/>
    <uses-feature android:name="android.hardware.camera"/>
    ...