[Android Q&A, Help & Troubleshooting] DavidD90:
Following the Google documentation I create an app that insert new events to the user's calendar.

In the following code you can see how I did it.

MakeRequastTask.class

/**
* An asynchronous task that handles the Google Calendar API call.
* Placing the API calls in their own task ensures the UI stays responsive.
*/
private class MakeRequestTask extends AsyncTask<Void, Void, String[][]> {
private com.google.api.services.calendar.Calendar mServiceCalendar = null;
private Exception mLastError = null;

private String[][] tempArray;
private SpreadSheet mSheet;

MakeRequestTask(GoogleAccountCredential credential, SpreadSheet mSheet) {
this.mSheet = mSheet;
tempArray = new String[7][2];
HttpTransport transport = AndroidHttp.newCompatibleTransport();
JsonFactory jsonFactory = JacksonFactory.getDefaultInstance();

mServiceCalendar = new com.google.api.services.calendar.Calendar.Builder(
transport, jsonFactory, credential)
.setApplicationName("Bank Of Israel")
.build();
}

/**
* Background task to call Google Calendar API.
* @param params no parameters needed for this task.
*/
@Override
protected String[][] doInBackground(Void... params) {
try {
setDataInCalendar();

} catch (Exception e) {
mLastError = e;
cancel(true);
return null;
}
return null;
}

//--- Google Calendar ---\\

private void setDataInCalendar() throws IOException {
Vector<Shift> temp = mSheet.getShifts();
for(Shift s: temp) {
Event e = createEvent(s);
String calendarId = userEmailAddress;
e = mServiceCalendar.events().insert(calendarId, e).execute();
Log.d("MyApp", "Event created: " + e.getHtmlLink());
}
}

private Event createEvent(Shift mShift) {
final String TimeOffSet = "-07:00";
Event event = new Event();
event.setSummary(mShift.getShiftName());//type
//set Date, Start & End Times
SimpleDateFormat sd = new SimpleDateFormat("yyyy-MM-dd");

//make a String for the DateTime Object
//format as: "yyyy-MM-ddTHH:mm:ss+UTCOffSet"
String startTimeUTC = sd.format(mShift.getShiftDate()) +"T"+
mShift.getStartTime().toString() + TimeOffSet ;
DateTime startDateTime = new DateTime(startTimeUTC);
EventDateTime start = new EventDateTime()
.setDateTime(startDateTime);

event.setStart(start);

String endTimeUTC;
//if the shift is C or C1 the end of the shift is in the next day
if (mShift.getShiftName().equals("c1")
||
mShift.getShiftName().equals("c")){
endTimeUTC = sd.format(PatternTest.oneDayForeword(mShift.getShiftDate())) +"T"+
mShift.getEndTime().toString()+ TimeOffSet;
}
else{
endTimeUTC = sd.format(mShift.getShiftDate()) +"T"+
mShift.getEndTime().toString() + IsraelTimeOffSet;
}
DateTime endDateTime = new DateTime(endTimeUTC);
EventDateTime end = new EventDateTime()
.setDateTime(endDateTime);

event.setEnd(end);

event.setColorId("10");
return event;
}
//------------------------------------------------------------------------------------\\
@Override
protected void onPreExecute() {
super.onPreExecute();
showProgressDialog();
}

@Override
protected void onPostExecute(String[][] strings) {
super.onPostExecute(strings);
hideProgressDialog();
Toast.makeText(SheetActivity.this, "Finish!", Toast.LENGTH_LONG).show();
}
}

@Override
protected void onCancelled() {
hideProgressDialog();
if (mLastError != null) {
if (mLastError instanceof GooglePlayServicesAvailabilityIOException) {
showGooglePlayServicesAvailabilityErrorDialog(
((GooglePlayServicesAvailabilityIOException) mLastError)
.getConnectionStatusCode());
} else if (mLastError instanceof UserRecoverableAuthIOException) {
startActivityForResult(
((UserRecoverableAuthIOException) mLastError).getIntent(),
SheetActivity.REQUEST_AUTHORIZATION);
}
else if (mLastError instanceof NoShiftsInFileException){
Toast.makeText(SheetActivity.this, mLastError.getMessage() , Toast.LENGTH_SHORT).show();
}
else if (mLastError instanceof NoUserNameException){
Toast.makeText(SheetActivity.this, mLastError.getMessage() , Toast.LENGTH_LONG).show();
finish();//go back to the SignIn Activity
}
else {
Toast.makeText(SheetActivity.this, "The following error occurred:\n"
+ mLastError.getMessage(), Toast.LENGTH_SHORT).show();
}
} else {
Toast.makeText(SheetActivity.this, "Request cancelled." , Toast.LENGTH_SHORT).show();
}
}
}

My problem is that after my app insert the new events, I can see them in the web Calendar but the Google Calendar App or any other calendar app I use on my smartphone (LG G2) doesn't show the new events (even after refreshing and resyncing), however when I'm inserting a new event using the web page the event sync perfectly with the apps on my phone.

Thank in advenc