TimerTask Crash in previewCallback

Question

Я использую TimerTask() в previewCallback для приложения. Однако он перестает работать. Я новичок в разработке Android, и я понятия не имею, что и где проблема. Я пытаюсь реагировать на предварительный просмотр камеры через 5 секунд. Я пробовал те же коды кода от if(isQrCodeScanned) до phoneCamera.autoFocus(autoFocusCallback); в функции onClick() без использования таймера, и он работает. Когда я нажимаю кнопку, предварительный просмотр камеры возобновляется. Однако, для TimerTask(), он падает.

private Timer timer; 
. 
. 
. 
timer.schedule(new TimerTask() 
      { 

      @Override 
      public void run() 
      { 

       if(isQrCodeScanned) 
       { 
        isQrCodeScanned = false; 
        isPreviewing = true;      
        qrCodeText.setText("Waiting for a QR Code..."); 

        phoneCamera.setPreviewCallback(previewCallback); 
        phoneCamera.startPreview(); 
        phoneCamera.autoFocus(autoFocusCallback); 
       } 

      }}, ACTIVATE_LIMIT); 

Благодарим за помощь!

Logcat:

03-03 13:04:42.927: W/Vold(29): No UMS switch available 
03-03 13:04:44.357: E/Zygote(33): setreuid() failed. errno: 2 
03-03 13:04:45.137: W/MediaProfiles(33): could not find media config xml file 
03-03 13:04:50.137: E/Zygote(33): setreuid() failed. errno: 17 
03-03 13:04:51.037: E/BatteryService(59): usbOnlinePath not found 
03-03 13:04:51.037: E/BatteryService(59): batteryVoltagePath not found 
03-03 13:04:51.037: E/BatteryService(59): batteryTemperaturePath not found 
03-03 13:04:51.056: E/SurfaceFlinger(59): Couldn't open /sys/power/wait_for_fb_sleep or /sys/power/wait_for_fb_wake 
03-03 13:04:51.557: W/zipro(69): Unable to open zip '/data/local/bootanimation.zip': No such file or directory 
03-03 13:04:51.557: W/zipro(69): Unable to open zip '/system/media/bootanimation.zip': No such file or directory 
03-03 13:04:52.457: W/PackageManager(59): Running ENG build: no pre-dexopt! 
03-03 13:04:54.607: W/PackageParser(59): No actions in intent filter at /data/app/ApiDemos.apk Binary XML file line #1841 
03-03 13:04:54.617: W/PackageParser(59): No actions in intent filter at /data/app/ApiDemos.apk Binary XML file line #1847 
03-03 13:04:54.627: W/PackageManager(59): Package com.example.android.apis desires unavailable shared library com.example.will.never.exist; ignoring! 
03-03 13:04:54.678: W/PackageManager(59): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH.mail in package com.android.contacts 
03-03 13:04:54.678: W/PackageManager(59): Unknown permission android.permission.ADD_SYSTEM_SERVICE in package com.android.phone 
03-03 13:04:54.678: W/PackageManager(59): Not granting permission android.permission.SEND_DOWNLOAD_COMPLETED_INTENTS to package com.android.browser (protectionLevel=2 flags=0x1be45) 
03-03 13:04:54.678: W/PackageManager(59): Unknown permission com.google.android.gm.permission.WRITE_GMAIL in package com.android.settings 
03-03 13:04:54.678: W/PackageManager(59): Unknown permission com.google.android.gm.permission.READ_GMAIL in package com.android.settings 
03-03 13:04:54.678: W/PackageManager(59): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH in package com.android.settings 
03-03 13:04:54.689: W/PackageManager(59): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH in package com.android.providers.contacts 
03-03 13:04:54.689: W/PackageManager(59): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH.cp in package com.android.providers.contacts 
03-03 13:04:54.689: W/PackageManager(59): Unknown permission com.google.android.googleapps.permission.ACCESS_GOOGLE_PASSWORD in package com.android.development 
03-03 13:04:54.689: W/PackageManager(59): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH in package com.android.development 
03-03 13:04:54.689: W/PackageManager(59): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH.ALL_SERVICES in package com.android.development 
03-03 13:04:54.689: W/PackageManager(59): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH.YouTubeUser in package com.android.development 
03-03 13:04:55.407: E/EventHub(59): could not get driver version for /dev/input/mouse0, Not a typewriter 
03-03 13:04:55.407: E/EventHub(59): could not get driver version for /dev/input/mice, Not a typewriter 
03-03 13:04:56.017: E/System(59): Failure starting core service 
03-03 13:04:56.017: E/System(59): java.lang.SecurityException 
03-03 13:04:56.017: E/System(59): at android.os.BinderProxy.transact(Native Method) 
03-03 13:04:56.017: E/System(59): at android.os.ServiceManagerProxy.addService(ServiceManagerNative.java:146) 
03-03 13:04:56.017: E/System(59): at android.os.ServiceManager.addService(ServiceManager.java:72) 
03-03 13:04:56.017: E/System(59): at com.android.server.ServerThread.run(SystemServer.java:184) 
03-03 13:04:56.557: W/AudioPolicyManagerBase(34): setPhoneState() setting same state 0 
03-03 13:04:56.577: E/SoundPool(59): error loading /system/media/audio/ui/Effect_Tick.ogg 
03-03 13:04:56.577: W/AudioService(59): Soundpool could not load file: /system/media/audio/ui/Effect_Tick.ogg 
03-03 13:04:56.577: E/SoundPool(59): error loading /system/media/audio/ui/KeypressStandard.ogg 
03-03 13:04:56.577: E/SoundPool(59): error loading /system/media/audio/ui/KeypressSpacebar.ogg 
03-03 13:04:56.577: W/AudioService(59): Soundpool could not load file: /system/media/audio/ui/KeypressSpacebar.ogg 
03-03 13:04:56.577: E/SoundPool(59): error loading /system/media/audio/ui/KeypressDelete.ogg 
03-03 13:04:56.577: W/AudioService(59): Soundpool could not load file: /system/media/audio/ui/KeypressDelete.ogg 
03-03 13:04:56.577: E/SoundPool(59): error loading /system/media/audio/ui/KeypressReturn.ogg 
03-03 13:04:56.577: W/AudioService(59): Soundpool could not load file: /system/media/audio/ui/KeypressReturn.ogg 
03-03 13:04:56.587: W/HeadsetObserver(59): This kernel does not have wired headset support 
03-03 13:04:56.587: W/DockObserver(59): This kernel does not have dock station support 
03-03 13:04:56.697: W/DevicePolicyManagerService(59): failed parsing /data/system/device_policies.xml java.io.FileNotFoundException: /data/system/device_policies.xml (No such file or directory) 
03-03 13:04:56.947: W/StatusBar(59): No icon ID for slot ime 
03-03 13:04:57.327: W/RecognitionManagerService(59): no available voice recognition services found 
03-03 13:04:57.498: E/ThrottleService(59): Could not open GPS configuration file /etc/gps.conf 
03-03 13:04:57.637: W/GpsLocationProvider(59): Could not open GPS configuration file /etc/gps.conf 
03-03 13:04:57.727: W/ActivityManager(59): Unable to start service Intent { act=@0 }: not found 
03-03 13:04:57.727: W/ActivityManager(59): Unable to start service Intent { act=@0 }: not found 
03-03 13:04:58.607: E/logwrapper(148): executing /system/bin/tc failed: No such file or directory 
03-03 13:04:58.647: E/logwrapper(149): executing /system/bin/tc failed: No such file or directory 
03-03 13:04:58.757: E/logwrapper(150): executing /system/bin/tc failed: No such file or directory 
03-03 13:05:01.617: W/ActivityManager(59): Unable to start service Intent { act=com.android.ussd.IExtendedNetworkService }: not found 
03-03 13:05:00.774: W/SystemClock(112): Unable to set rtc to 1362315900: Invalid argument 
03-03 13:05:05.370: E/HierarchicalStateMachine(59): TetherMaster - unhandledMessage: msg.what=3 
03-03 13:05:14.851: W/PackageManager(59): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH.mail in package com.android.contacts 
03-03 13:05:14.851: W/PackageManager(59): Unknown permission android.permission.ADD_SYSTEM_SERVICE in package com.android.phone 
03-03 13:05:14.851: W/PackageManager(59): Not granting permission android.permission.SEND_DOWNLOAD_COMPLETED_INTENTS to package com.android.browser (protectionLevel=2 flags=0x1be45) 
03-03 13:05:14.860: W/PackageManager(59): Unknown permission com.google.android.gm.permission.WRITE_GMAIL in package com.android.settings 
03-03 13:05:14.870: W/PackageManager(59): Unknown permission com.google.android.gm.permission.READ_GMAIL in package com.android.settings 
03-03 13:05:14.870: W/PackageManager(59): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH in package com.android.settings 
03-03 13:05:14.870: W/PackageManager(59): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH in package com.android.providers.contacts 
03-03 13:05:14.870: W/PackageManager(59): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH.cp in package com.android.providers.contacts 
03-03 13:05:14.870: W/PackageManager(59): Unknown permission com.google.android.googleapps.permission.ACCESS_GOOGLE_PASSWORD in package com.android.development 
03-03 13:05:14.881: W/PackageManager(59): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH in package com.android.development 
03-03 13:05:14.881: W/PackageManager(59): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH.ALL_SERVICES in package com.android.development 
03-03 13:05:14.881: W/PackageManager(59): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH.YouTubeUser in package com.android.development 
03-03 13:05:17.520: W/RecognitionManagerService(59): no available voice recognition services found 

А вот целая часть ошибочного кода previewCallback:

PreviewCallback previewCallback = new PreviewCallback() 
    { 
     public void onPreviewFrame(byte[] data, Camera camera) 
     { 
      . 
      . 
      . 

      if(scanResult != 0) 
      { 
       isPreviewing = false; 
       phoneCamera.setPreviewCallback(null); 
       phoneCamera.stopPreview(); 

       SymbolSet qrCodeContent = scanner.getResults(); 

       for(Symbol symbol : qrCodeContent) 
       { 
        qrCodeText.setText("QR CODE CONTAINS: " + symbol.getData()); 
        isQrCodeScanned = true; 
       } 

       timer.schedule(new TimerTask() 
           { 

            @Override 
            public void run() 
            { 
             // TODO Auto-generated method stub 

             if(isQrCodeScanned) 
             { 

              isQrCodeScanned = false; 
              isPreviewing = true; 

              qrCodeText.setText("Waiting for a QR Code..."); 

              phoneCamera.setPreviewCallback(previewCallback); 
              phoneCamera.startPreview(); 
              phoneCamera.autoFocus(autoFocusCallback); 
             } 

            } 

           }, ACTIVATE_LIMIT); 

      } 

     } 

    }; // End of previewCallback 

Answer 1

TimerTask работает в отдельном потоке и не может изменить положение вещей в UI- нить. Может быть, это сработает, если вы запустите код в потоке ui? Например:

timer.schedule(new TimerTask() { 
    @Override 
    public void run() { 
     if(isQrCodeScanned) { 
      isQrCodeScanned = false; 
      isPreviewing = true;      
      runOnUiThread(new Runnable() { 
       public void run() { 
        qrCodeText.setText("Waiting for a QR Code..."); 
        phoneCamera.setPreviewCallback(previewCallback); 
        phoneCamera.startPreview(); 
        phoneCamera.autoFocus(autoFocusCallback); 
       } 
      }); 
     } 
    } 
}, ACTIVATE_LIMIT); 

Не проверили это. Надеюсь, поможет.

Cheers, Martijn.