得到錯誤空指針異常嘗試調用虛擬方法

Question

得到錯誤已發生空指針異常，並試圖調用虛擬方法

public class after10th extends AppCompatActivity { 

    ArrayAdapter<String> adapter; 

    @Override 
    protected void onCreate(@Nullable Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.after10th); 

     ListView lv = (ListView) findViewById(R.id.searchten); 
     ArrayList<String> after_ten = new ArrayList<>(); 
     after_ten.addAll(Arrays.asList(getResources().getStringArray(R.array.after_ten))); 

     adapter = new ArrayAdapter<>(after10th.this, android.R.layout.simple_list_item_1, after_ten); 

     lv.setAdapter(adapter); 

    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     MenuInflater inflater = getMenuInflater(); 
     inflater.inflate(R.menu.menu_search, menu); 
     MenuItem item = menu.findItem(R.id.menusearchten); 
     SearchView searchView = (SearchView) item.getActionView(); 
     searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() { 
      @Override 
      public boolean onQueryTextSubmit(String query) { 
       return false; 
      } 

      @Override 
      public boolean onQueryTextChange(String newText) { 

       adapter.getFilter().filter(newText); 
       return false; 
      } 
     }); 

       return super.onCreateOptionsMenu(menu);`enter code here` 
    } 

} 

這是錯誤：

09-23 19:09： 17.242 9000-9000/com.example.supriya.career_guidance E/AndroidRuntime：致命異常：主

過程：com.example.supriya.career_guidance，PID：9000

顯示java.lang.NullPointerException：嘗試上的空對象引用調用虛擬方法「無效android.widget.SearchView.setOnQueryTextListener（android.widget.SearchView $ OnQueryTextListener）」

Answer 1

該錯誤消息幾乎徹底說該item.getActionView()返回null，在此行上：

SearchView searchView = (SearchView) item.getActionView();