如何使用onItemSelected方法？

Question

int I, E 
    String[] type; 
    Spinner firstSpinner ; 
    Spinner secondSpinner ; 
    Spinner thirdSpinner; 
    Spinner fourthSpinner;  

public void addItemsOnSpinner4(){ 
      Spinner firstSpinner = (Spinner) findViewById(R.id.spinner4); 
      ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this, 
        R.array.spinnerarraybool, android.R.layout.simple_spinner_item); 
      adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); 
      firstSpinner.setAdapter(adapter); 
     }  
     //ACTIONS THAT TAKE PLACE WHEN SPINNER OPTION IS CHOSEN 
     public void onItemSelected(AdapterView<?> parent, View view, int arg2, 
       long arg3) { 
      switch (parent.getId()){ 
      case R.id.spinner4: 
       String firstAnswer = firstSpinner.getSelectedItem().toString(); 
       if (firstAnswer.equals("True")){ 
        E += 1; 
       } 
       if (firstAnswer.equals("In the Middle")){ 
        E += 1; 
        I += 1; 
       } 
       if (firstAnswer.equals("False")){ 
        I += 1; 
       } 
       break; 


<STRINGSXMLstring-array name="spinnerarraybool"> 
    <item>True</item> 
    <item>In the Middle</item> 
    <item>False</item> 
</STRINGSXMLstring-array> 

E和I的值不會改變，並保持爲0.如何修復我的onItemSelected方法以使它們發生更改。我想我和E上去，每當我在微調選擇一個選項

Answer 1

你忘了設置適配器

Answer 2

firstSpinner.setOnItemSelectedListener(new OnItemSelectedListener() 
     { 
      @Override 
      public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) 
      { 

      } 

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

      } 
     }); 

之後調用 firstSpinner.setOnItemSelectedListener(this);