Wie kann ich meinen Spinner-Wert abrufen, wenn ich Kalender verwende

Question

Ich verwende Spinner, um das Datum in der Kalenderklasse anzuzeigen.

Ich kann das Jahr und den Monat bekommen, aber ich kann nicht Tag Wert auf spinner bekommen.

Es zeigt

java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.Object.toString()' on a null object reference 

Wie kann ich das Problem beheben? Hier

ist der Code:

private void datePick(){ 
     Calendar calendar = Calendar.getInstance(); 

     for (int i = 0; i < 100; i++) { 
      dataYear.add("" + (calendar.get(Calendar.YEAR) - i)); 
     } 

     adapterSpYear = new ArrayAdapter<String>(getActivity(), R.layout.spinner, dataYear); 
     adapterSpYear.setDropDownViewResource(R.layout.support_simple_spinner_dropdown_item); 
     spYear.setAdapter(adapterSpYear); 
     spYear.setSelection(34);//for 1982 

     for (int i = 1; i <= 12; i++) { 
      dataMonth.add("" + (i < 10 ? "0" + i : i)); 
     } 

     adapterSpMonth = new ArrayAdapter<String>(getActivity(), R.layout.spinner, dataMonth); 
     adapterSpMonth.setDropDownViewResource(R.layout.support_simple_spinner_dropdown_item); 
     spMonth.setAdapter(adapterSpMonth); 


     adapterSpDay = new ArrayAdapter<String>(getActivity(), R.layout.spinner, dataDay); 
     adapterSpDay.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); 
     spDay.setAdapter(adapterSpDay); 

     spMonth.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { 
      @Override 
      public void onItemSelected(AdapterView<?> adapterView, View view, int arg2, long arg3) { 
       dataDay.clear(); 
       Calendar calendar1 = Calendar.getInstance(); 
       calendar1.set(Calendar.YEAR, Integer.valueOf(spYear.getSelectedItem().toString())); 
       calendar1.set(Calendar.MONTH, arg2); 
       int dayOfMonth = calendar1.getActualMaximum(Calendar.DAY_OF_MONTH); 
       for (int i = 1; i <= dayOfMonth; i++) { 
        dataDay.add("" + (i < 10 ? "0" + i : i)); 
       } 
       adapterSpDay.notifyDataSetChanged(); 


       String year=spYear.getSelectedItem().toString(); 
       String month=spMonth.getSelectedItem().toString(); 
       String day=spDay.getSelectedItem().toString(); 

       Log.i("test",".>>>>Year>>>>"+year); 
       Log.i("test",".>>>>Month>>>>"+month); 
       Log.i("test",".>>>>Day>>>>"+day); 
      } 

      @Override 
      public void onNothingSelected(AdapterView<?> adapterView) { 

      } 
     }); 
    } 

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Answer 1

In Spinner Adapter adapterSpDay.notifyDataSetChanged(); werden nicht die Adapterdaten aktualisieren. Sie müssen Adapter und Set-Adapter für Tag schaffen wieder innerhalb

spMonth.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { 
      @Override 
      public void onItemSelected(AdapterView<?> adapterView, View view, int arg2, long arg3) 
      { // Here create adapter for day again by passing new data and set that adapter to day spinner. 
       ............ 
         }