相机NullPointerException异常误差参数

Question

我有以下代码：

Line Code 
193 private Camera mCamera; 
<!-- NO CALLS TO mCamera HERE --> 
229 mCamera = Camera.open(); 
230 Camera.Parameters p = mCamera.getParameters(); 

当我运行应用程序，我得到以下堆栈跟踪：

04-08 20:56:45.330: E/AndroidRuntime(570): FATAL EXCEPTION: main 
04-08 20:56:45.330: E/AndroidRuntime(570): java.lang.NullPointerException 
04-08 20:56:45.330: E/AndroidRuntime(570): at com.soloman.cbc.FullscreenActivity$MySurfaceView.surfaceCreated(FullscreenActivity.java:230) 
04-08 20:56:45.330: E/AndroidRuntime(570): at android.view.SurfaceView.updateWindow(SurfaceView.java:569) 
04-08 20:56:45.330: E/AndroidRuntime(570): at android.view.SurfaceView.access$000(SurfaceView.java:86) 
04-08 20:56:45.330: E/AndroidRuntime(570): at android.view.SurfaceView$3.onPreDraw(SurfaceView.java:174) 
04-08 20:56:45.330: E/AndroidRuntime(570): at android.view.ViewTreeObserver.dispatchOnPreDraw(ViewTreeObserver.java:680) 
04-08 20:56:45.330: E/AndroidRuntime(570): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1842) 
04-08 20:56:45.330: E/AndroidRuntime(570): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:989) 
04-08 20:56:45.330: E/AndroidRuntime(570): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4351) 
04-08 20:56:45.330: E/AndroidRuntime(570): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749) 
04-08 20:56:45.330: E/AndroidRuntime(570): at android.view.Choreographer.doCallbacks(Choreographer.java:562) 
04-08 20:56:45.330: E/AndroidRuntime(570): at android.view.Choreographer.doFrame(Choreographer.java:532) 
04-08 20:56:45.330: E/AndroidRuntime(570): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735) 
04-08 20:56:45.330: E/AndroidRuntime(570): at android.os.Handler.handleCallback(Handler.java:725) 
04-08 20:56:45.330: E/AndroidRuntime(570): at android.os.Handler.dispatchMessage(Handler.java:92) 
04-08 20:56:45.330: E/AndroidRuntime(570): at android.os.Looper.loop(Looper.java:137) 
04-08 20:56:45.330: E/AndroidRuntime(570): at android.app.ActivityThread.main(ActivityThread.java:5039) 
04-08 20:56:45.330: E/AndroidRuntime(570): at java.lang.reflect.Method.invokeNative(Native Method) 
04-08 20:56:45.330: E/AndroidRuntime(570): at java.lang.reflect.Method.invoke(Method.java:511) 
04-08 20:56:45.330: E/AndroidRuntime(570): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
04-08 20:56:45.330: E/AndroidRuntime(570): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
04-08 20:56:45.330: E/AndroidRuntime(570): at dalvik.system.NativeStart.main(Native Method) 

我使用的代码是从How can I manipulate the camera preview?

我有CAMERA permission在AndroidManifest.xml，和所有imports都占。有没有人有任何建议如何解决这个错误？

谢谢。

Answer 1

在设备上，而不朝后相机Camera.open()返回null。尝试Camera.open(0)以获得前置摄像头。

Answer 2

如果机器人版本早于3.0使用

getHolder().setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);