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2012-12-27 50 views
0

獲取位圖我有這樣的代碼將項目添加到一個ArrayList：從資源

public Questions(int questionMode) { 
      getID = new Random(); 
      allQuestions = new ArrayList<Question>(); 

      allQuestions.add(new Question(2, 0, 0, 2, 5, (BitmapFactory.decodeResource(getResources(), R.drawable.flag_dutch)), "The Netherlands", true)); //<-- error at this line 
     }

我在類的構造函數intilize allQuestions，但是當我運行的代碼，我得到一個NullPointerException。這是我的logcat：

12-27 18:14:25.335: E/InputEventReceiver(3583): Exception dispatching input event. 
12-27 18:14:25.335: E/MessageQueue-JNI(3583): Exception in MessageQueue callback: handleReceiveCallback 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): java.lang.NullPointerException 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.content.ContextWrapper.getResources(ContextWrapper.java:81) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at com.obattech.twoplayergame.Questions.createFlagQuestions(Questions.java:80) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at com.obattech.twoplayergame.Questions.<init>(Questions.java:54) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at com.obattech.twoplayergame.games.GuessFlag.startCountDown(GuessFlag.java:199) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at com.obattech.twoplayergame.games.GuessFlag$1.onTouch(GuessFlag.java:75) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.view.View.dispatchTouchEvent(View.java:7332) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2416) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2117) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2416) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2117) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2416) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2117) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2416) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2117) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2115) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1468) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.app.Activity.dispatchTouchEvent(Activity.java:2487) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2063) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.view.View.dispatchPointerEvent(View.java:7520) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:3376) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:3308) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:4402) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:4380) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:4484) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:171) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.os.MessageQueue.nativePollOnce(Native Method) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.os.MessageQueue.next(MessageQueue.java:125) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.os.Looper.loop(Looper.java:124) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at android.app.ActivityThread.main(ActivityThread.java:4898) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at java.lang.reflect.Method.invokeNative(Native Method) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at java.lang.reflect.Method.invoke(Method.java:511) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773) 
12-27 18:14:25.340: E/MessageQueue-JNI(3583): at dalvik.system.NativeStart.main(Native Method) 
12-27 18:14:25.340: D/AndroidRuntime(3583): Shutting down VM 
12-27 18:14:25.340: W/dalvikvm(3583): threadid=1: thread exiting with uncaught exception (group=0x410e72a0) 
12-27 18:14:25.350: E/AndroidRuntime(3583): FATAL EXCEPTION: main 
12-27 18:14:25.350: E/AndroidRuntime(3583): java.lang.NullPointerException 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.content.ContextWrapper.getResources(ContextWrapper.java:81) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at com.obattech.twoplayergame.Questions.createFlagQuestions(Questions.java:80) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at com.obattech.twoplayergame.Questions.<init>(Questions.java:54) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at com.obattech.twoplayergame.games.GuessFlag.startCountDown(GuessFlag.java:199) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at com.obattech.twoplayergame.games.GuessFlag$1.onTouch(GuessFlag.java:75) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.view.View.dispatchTouchEvent(View.java:7332) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2416) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2117) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2416) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2117) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2416) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2117) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2416) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2117) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2115) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1468) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.app.Activity.dispatchTouchEvent(Activity.java:2487) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2063) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.view.View.dispatchPointerEvent(View.java:7520) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:3376) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:3308) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:4402) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:4380) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:4484) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:171) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.os.MessageQueue.nativePollOnce(Native Method) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.os.MessageQueue.next(MessageQueue.java:125) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.os.Looper.loop(Looper.java:124) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at android.app.ActivityThread.main(ActivityThread.java:4898) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at java.lang.reflect.Method.invokeNative(Native Method) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at java.lang.reflect.Method.invoke(Method.java:511) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773) 
12-27 18:14:25.350: E/AndroidRuntime(3583):  at dalvik.system.NativeStart.main(Native Method)

我認爲這是與從資源獲得一個位圖，但我無法弄清楚如何解決它。

來源

2012-12-27 ObAt

回答

2

我假設Questions是你的Activity，因爲你使用它作爲getResources()的參考。

既然如此，你不能把東西放在構造函數中（除了可能的初始化變量），並期望它們工作; Activity的資源尚未準備好在此時使用。使用onCreate()代替：

@Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     getID = new Random(); 
     allQuestions = new ArrayList<Question>(); 

     allQuestions.add(new Question(2, 0, 0, 2, 5, (BitmapFactory.decodeResource(getResources(), R.drawable.flag_dutch)), "The Netherlands", true)); //<-- error at this line 
    }

來源

2012-12-27 17:23:48 Eric

0

你有一個空指針的位置：Questions.java:80

您需要包括該代碼真正知道問題是什麼。這在StackTrace中報告（只需從頂部開始，然後讀取，直到看到代碼爲止）。

來源

2012-12-27 17:25:00 Booger

+0

OP知道這一點，並且對導致問題的行（即第80行）發出了'// //註釋。我認爲這個答案更適合作爲評論... – Eric

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