閃光燈開啓時應用程序崩潰

Question

使用在How to turn on camera flash light programmatically in Android?處找到的代碼，我嘗試打開手電筒。我用來測試的設備是Galaxy SIII。以下是我的java文件中的代碼。

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

在清單文件中，聲明瞭以下權限。

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

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

但是，當我嘗試從手機上的應用程序打開手電筒時，應用程序崩潰。我猜測這可能是因爲設備本身不支持手電筒。該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): !@Dumpstate > 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): !@Sync 8677 

我應該爲了使這項工作或我怎麼能先檢查設備是否支持閃光燈打開呢？

Answer 1

攝像頭服務獲取失敗，在你的情況。這可能是由於很多原因造成的。另一項服務可能使用相機，可能沒有發佈它。有可能是設備（未在GS3）等

上沒有攝像頭查看更多信息這些線程用於診斷您的具體問題：

Failed to connect to camera service

Fail to connect to camera service

Android: Fail to connect to camera service at Camera.open();

Android - Fail to connect to camera