问题
In a previous post, I got this error when starting the camera application in an emulator with a webcam connected:
CameraService::connect X (pid 702) rejected (invalid cameraId 0).
After updating the dev tools, I got this other error instead (then, after making a new emulator, I got the first error again):
03-15 03:44:04.272: E/EmulatedCamera_QemuClient(40): queryStart: Query failed: Cannot start the camera
03-15 03:44:04.272: E/EmulatedCamera_QemuDevice(40): startDevice: Unable to start device 'AndroidEmulatorVC0' for NV21[640x480] frames
[...]
03-15 03:31:15.922: E/AndroidRuntime(785): FATAL EXCEPTION: Thread-76
03-15 03:31:15.922: E/AndroidRuntime(785): java.lang.RuntimeException: startPreview failed
03-15 03:31:15.922: E/AndroidRuntime(785): at com.android.camera.Camera.startPreview(Camera.java:1867)
03-15 03:31:15.922: E/AndroidRuntime(785): at com.android.camera.Camera.access$3100(Camera.java:87)
03-15 03:31:15.922: E/AndroidRuntime(785): at com.android.camera.Camera$5.run(Camera.java:1112)
03-15 03:31:15.922: E/AndroidRuntime(785): at java.lang.Thread.run(Thread.java:856)
03-15 03:31:15.922: E/AndroidRuntime(785): Caused by: java.lang.RuntimeException: startPreview failed
03-15 03:31:15.922: E/AndroidRuntime(785): at android.hardware.Camera.startPreview(Native Method)
03-15 03:31:15.922: E/AndroidRuntime(785): at com.android.camera.Camera.startPreview(Camera.java:1864)
03-15 03:31:15.922: E/AndroidRuntime(785): ... 3 more
What is causing this error? How can I best troubleshoot this?
来源：https://stackoverflow.com/questions/15424606/android-error-using-webcam-in-emulator