Android - Time Zone Demo

You will get Final Output:

Step 1 MainActivity.java

First create new Android Project. Add Following into your Main Activity class

private Spinner spinnerAvailableID;
private Calendar current;
private TextView textTimeZone, txtCurrentTime, txtTimeZoneTime;
private long miliSeconds;
private ArrayAdapter<String> idAdapter;
private SimpleDateFormat sdf;
private Date resultdate;

Then in our Main Activity class we need all IDs of the different Time Zone. So we use.

String[] idArray = TimeZone.getAvailableIDs();

Step 2 getGMTTime() method implementation

Add new method for converting the current time into GMT (Greenwich Mean Time).

private void getGMTTime() {
current = Calendar.getInstance();
txtCurrentTime.setText("" + current.getTime());
 
miliSeconds = current.getTimeInMillis();
 
TimeZone tzCurrent = current.getTimeZone();
int offset = tzCurrent.getRawOffset();
if (tzCurrent.inDaylightTime(new Date())) {
offset = offset + tzCurrent.getDSTSavings();
}
 
miliSeconds = miliSeconds - offset;
 
resultdate = new Date(miliSeconds);
System.out.println(sdf.format(resultdate));
}

To know more about Calendar class please follow the link:

• http://developer.android.com/reference/java/util/Calendar.html

Step 3 onCreate() Method

Then Add the following code into your onCreate() method.

        spinnerAvailableID = (Spinner) findViewById(R.id.availableID);
textTimeZone = (TextView) findViewById(R.id.timezone);
txtCurrentTime = (TextView) findViewById(R.id.txtCurrentTime);
txtTimeZoneTime = (TextView) findViewById(R.id.txtTimeZoneTime);
 
sdf = new SimpleDateFormat("EEEE, dd MMMM yyyy HH:mm:ss");
 
idAdapter = new ArrayAdapter<String>(this,
android.R.layout.simple_spinner_item, idArray);
 
idAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinnerAvailableID.setAdapter(idAdapter);
 
getGMTTime();
 
spinnerAvailableID
.setOnItemSelectedListener(new OnItemSelectedListener() {
 
@Override
public void onItemSelected(AdapterView<?> parent,
View view, int position, long id) {
getGMTTime();
String selectedId = (String) (parent
.getItemAtPosition(position));
 
TimeZone timezone = TimeZone.getTimeZone(selectedId);
String TimeZoneName = timezone.getDisplayName();
 
int TimeZoneOffset = timezone.getRawOffset()
/ (60 * 1000);
 
int hrs = TimeZoneOffset / 60;
int mins = TimeZoneOffset % 60;
 
miliSeconds = miliSeconds + timezone.getRawOffset();
 
resultdate = new Date(miliSeconds);
System.out.println(sdf.format(resultdate));
 
textTimeZone.setText(TimeZoneName + " : GMT " + hrs + "."
+ mins);
txtTimeZoneTime.setText("" + sdf.format(resultdate));
miliSeconds = 0;
}
 
@Override
public void onNothingSelected(AdapterView<?> arg0) {
 
}
});

More information about SimpleDateFormat class please follow the link:

• http://developer.android.com/reference/java/text/SimpleDateFormat.html

I hope you enjoy this tutorial and it would be helpful to you.

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An entrepreneur who has founded 2 flourishing software firms in 7 years, Tejas is keen to understand everything about gaming - from the business dynamics to awesome designs to gamer psychology. As the founder-CEO of a company that has released some very successful games, he knows a thing or two about gaming. He shares his knowledge through blogs and talks that he gets invited to.