闪光灯开启时应用程序崩溃

使用在How to turn on camera flash light programmatically in Android?处找到的代码，我尝试打开手电筒。我用来测试的设备是Galaxy SIII。以下是我的java文件中的代码。闪光灯开启时应用程序崩溃

camera = Camera.open(); 
Parameters p = camera.getParameters(); 
p.setFlashMode(Parameters.FLASH_MODE_TORCH); 
camera.setParameters(p); 
camera.startPreview();

在清单文件中，声明了以下权限。

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

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

但是，当我尝试从手机上的应用程序打开手电筒时，应用程序崩溃。我猜测这可能是因为设备本身不支持手电筒。该logcat的是如下

05-17 07:52:30.489: E/AudioPolicyService(1902): getOutput() tid 17220 ++ 
05-17 07:52:30.489: E/AudioPolicyService(1902): getOutput() tid 17220 -- 
05-17 07:52:30.489: E/AudioPolicyService(1902): getOutput() tid 1902 ++ 
05-17 07:52:30.489: E/AudioPolicyService(1902): getOutput() tid 1902 -- 
05-17 07:52:30.489: E/AudioPolicyService(1902): getOutput() tid 2204 ++ 
05-17 07:52:30.489: E/AudioPolicyService(1902): getOutput() tid 2204 -- 
05-17 07:52:30.504: E/AudioMixer(1902): MOON > checkSEC_PCM ++ 1 
05-17 07:52:30.504: E/AudioMixer(1902): MOON > checkSEC_PCM ++ 1 
05-17 07:52:30.504: E/AudioResampler(1902): Unsupported sample format, 1 bits, 1 channels 
05-17 07:52:30.619: E/AndroidRuntime(4740): FATAL EXCEPTION: main 
05-17 07:52:30.619: E/AndroidRuntime(4740): java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=1, result=-1, data=Intent { (has extras) }} to activity {com.example.app/com.example.app$Potter}: java.lang.RuntimeException: Fail to connect to camera service 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at android.app.ActivityThread.deliverResults(ActivityThread.java:3182) 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at android.app.ActivityThread.handleSendResult(ActivityThread.java:3225) 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at android.app.ActivityThread.access$1100(ActivityThread.java:140) 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1275) 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at android.os.Handler.dispatchMessage(Handler.java:99) 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at android.os.Looper.loop(Looper.java:137) 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at android.app.ActivityThread.main(ActivityThread.java:4898) 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at java.lang.reflect.Method.invokeNative(Native Method) 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at java.lang.reflect.Method.invoke(Method.java:511) 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006) 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773) 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at dalvik.system.NativeStart.main(Native Method) 
05-17 07:52:30.619: E/AndroidRuntime(4740): Caused by: java.lang.RuntimeException: Fail to connect to camera service 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at android.hardware.Camera.native_setup(Native Method) 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at android.hardware.Camera.<init>(Camera.java:348) 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at android.hardware.Camera.open(Camera.java:325) 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at com.example.app.MainActivity$Potter.startActivityWithName(MainActivity.java:100) 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at com.example.app.MainActivity$Potter.onActivityResult(MainActivity.java:183) 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at android.app.Activity.dispatchActivityResult(Activity.java:5390) 
05-17 07:52:30.619: E/AndroidRuntime(4740):  at android.app.ActivityThread.deliverResults(ActivityThread.java:3178) 
05-17 07:52:30.619: E/AndroidRuntime(4740):  ... 11 more 
05-17 07:52:30.664: E/android.os.Debug(2271): [email protected] > dumpstate -k -t -z -d -o /data/log/dumpstate_app_error 
05-17 07:52:38.849: E/MtpService(2094): In MTPAPP onReceive:android.intent.action.BATTERY_CHANGED 
05-17 07:52:38.849: E/MtpService(2094): battPlugged Type : 2 
05-17 07:52:39.419: E/Launcher(22785): Error finding setting, default accessibility to not found: accessibility_enabled 
05-17 07:52:44.159: E/Watchdog(2271): [email protected] 8677

我应该为了使这项工作或我怎么能先检查设备是否支持闪光灯打开呢？

来源

2013-05-17 Ankush