Spinner: NullPointerException at ArrayAdapter.createViewFromResource
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I create some Spinners by code like this :

    viewToLoad = LayoutInflater.from(this.getParent()).inflate(R.layout.producttheme, null);
    this.setContentView(viewToLoad);

    product_spinner[i] = new Spinner(viewToLoad.getContext());
    product_spinner[i].setLayoutParams(lp_spinner);
    product_spinner[i].setBackgroundResource(R.drawable.spinner_selector);
    
    ArrayAdapter spinnerAdapter = new ArrayAdapter(viewToLoad.getContext(),  com.Orange.R.layout.my_spinner_textview, spinnerA); //spinnerA is a String[]
    spinnerAdapter.setDropDownViewResource(com.Orange.R.layout.multiline_spinner_dropdown_item);
    product_spinner[i].setAdapter(spinnerAdapter);
                         
It appear fine on screen but when I click it I get this error :

    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	java.lang.NullPointerException
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:355)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at android.widget.ArrayAdapter.getDropDownView(ArrayAdapter.java:376)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at android.widget.Spinner$DropDownAdapter.getDropDownView(Spinner.java:329)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at android.widget.Spinner$DropDownAdapter.getView(Spinner.java:325)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at android.widget.AbsListView.obtainView(AbsListView.java:1294)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at android.widget.ListView.measureHeightOfChildren(ListView.java:1198)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at android.widget.ListView.onMeasure(ListView.java:1109)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at android.view.View.measure(View.java:8171)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3132)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1012)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at android.widget.LinearLayout.measureVertical(LinearLayout.java:381)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at android.widget.LinearLayout.onMeasure(LinearLayout.java:304)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at com.android.internal.widget.WeightedLinearLayout.onMeasure(WeightedLinearLayout.java:60)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at android.view.ViewRoot.performTraversals(ViewRoot.java:801)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at android.view.ViewRoot.handleMessage(ViewRoot.java:1727)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at android.os.Handler.dispatchMessage(Handler.java:99)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at android.os.Looper.loop(Looper.java:123)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at android.app.ActivityThread.main(ActivityThread.java:4627)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at java.lang.reflect.Method.invokeNative(Native Method)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at java.lang.reflect.Method.invoke(Method.java:521)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
    15:53:22.040	8716	com.Orange	ERROR	AndroidRuntime	    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)

First Spinner added works fine, but for the second Spinner I get this error. 
I have no idea why I get a nullpointer at AdapterArray.createViewFromResources because I don't use this method. Where is my mistake? 