如何在UTC中显示所选时区的吐司

Question

I want to show the toast message of UTC time from the selected timezone from the spinner list shown in Image below.

below is my code:

 Spinner tz;
 tz = (Spinner) findViewById(R.id.edit);


    String[] idArray = TimeZone.getAvailableIDs();
    ArrayAdapter<String> idAdapter = new ArrayAdapter<>(getApplicationContext(),R.layout.custom,idArray);
    idAdapter.setDropDownViewResource(R.layout.custom);
    tz.setAdapter(idAdapter);


    for(int i = 0; i < idAdapter.getCount(); i++) {
        if(idAdapter.getItem(i).equals(TimeZone.getDefault().getID())) {
             tz.setSelection(i);


        }
    }

I have tried this but cannot get my result

http://developer.android.com/reference/java/util/TimeZone.html#getDisplayName%28boolean

Answer 1

You must use setOnItemSelectedListener for this purpose. An example usage is shown below.

tz.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {

            SimpleDateFormat df = new SimpleDateFormat("dd MMM HH:mm a", Locale.getDefault());
            df.setTimeZone(TimeZone.getTimeZone(idAdapter.getItem(position))); //format in given timezone
            String strDate = df.format((new Date()).getTime());
            //Display the Toast
            Toast.makeText(getApplicationContext(), strDate, Toast.LENGTH_LONG).show();
        }

        @Override
        public void onNothingSelected(AdapterView<?> parentView) {
            // your code here
        }

    });

Note that onItemSelected method is also invoked when the view is being build, so may consider putting it inside onCreate() method call.

Hope this helps.

Answer 2

Not sure if I understand your question right, but: You are saying that you want to display the time of the different timezones in UTC? UTC is a timezone so the time in UTC will always be the same time for each of your selections. You probably want to display the local time of the selected timezone, and not UTC.

To do so use : System.currentTimeMillis() it gives you the number of milliseconds since January 1, 1970 00:00:00 UTC.

With DateFormat you can set your timezone and convert it to the local time.

DateFormat df = DateFormat.getTimeInstance();
//Here set the timezone according to the selection in your spinner 
df.setTimeZone(TimeZone.getTimeZone("gmt")); 
String gmtTime = df.format(new Date());

Hope this helps Cheers

Answer 3

并制作吐司，使用

Toast.makeText(getApplicationContext(),gmtTime,Toast.LENGTH_SHORT)