public class MainActivity extends AppCompatActivity implements

 CalendarViewPagerFragment.OnPageChangeListener,

 CalendarViewFragment.OnDateClickListener,

 CalendarViewFragment.OnDateCancelListener {

 

 private TextView tv_date;

 private boolean isChoiceModelSingle = false;

 private List<CalendarDate> mListDate = new ArrayList<>();

 

 @Override

 protected void onCreate(Bundle savedInstanceState) {

 super.onCreate(savedInstanceState);

 setContentView(R.layout.activity_main);

 tv_date = (TextView) findViewById(R.id.tv_date);

 initFragment();

 }

 

 private void initFragment(){

 FragmentManager fm = getSupportFragmentManager();

 FragmentTransaction tx = fm.beginTransaction();

 // Fragment fragment = new CalendarViewPagerFragment();

 Fragment fragment = CalendarViewPagerFragment.newInstance(isChoiceModelSingle);

 tx.replace(R.id.fl_content, fragment);

 tx.commit();

 }

 

 

 @Override

 public boolean onCreateOptionsMenu(Menu menu) {

 getMenuInflater().inflate(R.menu.menu_im, menu);

 return true;

 }

 @Override

 public boolean onOptionsItemSelected(MenuItem item) {

 switch (item.getItemId()) {

  case R.id.menu_single:

  isChoiceModelSingle = true;

  initFragment();

  break;

  case R.id.menu_multi:

  isChoiceModelSingle = false;

  initFragment();

  break;

  default:

  break;

 }

 return true;

 }

 @Override

 public void OnDateClick(CalendarDate calendarDate) {

 

 int year = calendarDate.getSolar().solarYear;

 int month = calendarDate.getSolar().solarMonth;

 int day = calendarDate.getSolar().solarDay;

 if (isChoiceModelSingle) {

  tv_date.setText(year + "-" + month + "-" + day);

 } else {

  //System.out.println(calendarDate.getSolar().solarDay);

  mListDate.add(calendarDate);

  tv_date.setText(listToString(mListDate));

 }

 

 }

 

 @Override

 public void OnDateCancel(CalendarDate calendarDate) {

 int count = mListDate.size();

 for (int i = 0; i < count; i++) {

  CalendarDate date = mListDate.get(i);

  if (date.getSolar().solarDay == calendarDate.getSolar().solarDay) {

  mListDate.remove(i);

  break;

  }

 }

 tv_date.setText(listToString(mListDate));

 }

 

 @Override

 public void OnPageChange(int year, int month) {

 tv_date.setText(year + "-" + month);

 mListDate.clear();

 }

 

 private static String listToString(List<CalendarDate> list) {

 StringBuffer stringBuffer = new StringBuffer();

 for (CalendarDate date : list) {

  stringBuffer.append(date.getSolar().solarYear + "-" + date.getSolar().solarMonth + "-" + date.getSolar().solarDay).append(" ");

 }

 return stringBuffer.toString();

 }

 

}

 if (isChoiceModelSingle) {
  mGridView.setChoiceMode(GridView.CHOICE_MODE_SINGLE);
 } else {
  mGridView.setChoiceMode(GridView.CHOICE_MODE_MULTIPLE);
 }
 mGridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
  @Override
  public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
  CalendarDate calendarDate = ((CalendarGridViewAdapter) mGridView.getAdapter()).getListData().get(position);
  if (isChoiceModelSingle) {
   //單選
   if (finalMListDataCalendar.get(position).isInThisMonth()) {
   onDateClickListener.OnDateClick(calendarDate);
   } else {
   mGridView.setItemChecked(position, false);
   }
  } else {
   //多選
   if (finalMListDataCalendar.get(position).isInThisMonth()) {
   // mGridView.getCheckedItemIds()
   if(!mGridView.isItemChecked(position)){
    onDateCancelListener.OnDateCancel(calendarDate);
   } else {
    onDateClickListener.OnDateClick(calendarDate);
   }
 
   } else {
   mGridView.setItemChecked(position, false);
   }
 
  }
  }
 });