Android 如何定义日期选择器对话框？

这是我的主要活动代码包含错误

 public class MainActivity extends Activity{  
     static EditText bdayText;
     DBHandler dbHandler = new DBHandler(this); 
   @Override 
protected void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.activity_main);    
}

日期选择器方法

public void selectDate(View view) {

        DialogFragment newFragment = new DialogFragment();
        newFragment.show(getFragmentManager(), "DatePicker");

    }

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. 检查此项并将此DBHandler DBHandler=new DBHandlerthis inside OnCreate感谢该链接frnd。我尝试过，在显示datepicker时没有问题，但在设置日期时，在日志cat java.lang.NullPointerException..tv.setTextdate中显示了一些错误；和listener.returnDatedate。请在这方面帮助我…你需要实现在对话框片段中定义的接口，还要确保你已经在OnCreateEverything中初始化了textview tv。谢谢你。愚蠢的错误，我已经将textview初始化为静态，现在更改了它，，，开始工作了。。！！！。再次感谢..如果有帮助的话，你可以在发布的链接中更新答案

  public static void setTheDate(int year, int month, int day) {
        having error in this line
          bdayText = (EditText)MainActivity().findViewById(R.id.editText5);
          bdayText.setText(day+"/"+month+"/"+year);
        }

 public static class SelectDateFragment extends DialogFragment implements DatePickerDialog.OnDateSetListener {
     @Override
     public Dialog onCreateDialog(Bundle savedInstanceState) {


         final Calendar c = Calendar.getInstance();
         int yy = c.get(Calendar.YEAR);
         int mm = c.get(Calendar.MONTH);
         int dd = c.get(Calendar.DAY_OF_MONTH);

         DatePickerDialog dialog = new DatePickerDialog(getActivity(),this,c.YEAR, c.MONTH, c.DATE);

         dialog.getDatePicker().setCalendarViewShown(false);
         dialog.setTitle("Pick a date");
         return dialog;
     }
     public void onDateSet(DatePicker view, int yy, int mm, int dd) {

         setTheDate(yy, mm+1, dd);
     }