我这样写为什么点按钮没任何反应呢

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.layout);
}
public void myclick(View V){
    switch (V.getId()){
        case R.id.BU1:
            showTime();
            break;
    }
}


private void showTime() {
    Calendar calendar=Calendar.getInstance();
    year=calendar.get(calendar.YEAR);
    month=calendar.get(calendar.MONTH);
    Day=calendar.get(calendar.DAY_OF_MONTH);
    DatePickerDialog dialog=new DatePickerDialog(MainActivity.this, new DatePickerDialog.OnDateSetListener() {
        @Override
        public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
            Toast.makeText(MainActivity.this,year+"年"+monthOfYear+"月"+dayOfMonth+"日",Toast.LENGTH_SHORT).show();
        }
    },year,month,Day);
    dialog.setTitle("标题");
    dialog.show();
}