Get system date/time and display in formatted form

MainActivity.java

package com.blogspot.android_er.androiddatetime;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;

public class MainActivity extends AppCompatActivity {

    TextView tvNow, tvNowFormatted1, tvNowFormatted2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tvNow = (TextView)findViewById(R.id.now);
        tvNowFormatted1 = (TextView)findViewById(R.id.nowformatted1);
        tvNowFormatted2 = (TextView)findViewById(R.id.nowformatted2);

        Date now = new Date();
        tvNow.setText(now.toString());

        String nowFormatted1 = DateFormat.getDateTimeInstance().format(now);
        tvNowFormatted1.setText(nowFormatted1);

        String nowFormatted2 = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss").format(now);
        tvNowFormatted2.setText(nowFormatted2);
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_margin="20dp"
    android:orientation="vertical"
    tools:context="com.blogspot.android_er.androiddatetime.MainActivity">

    <TextView
        android:id="@+id/title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold"/>

    <TextView
        android:id="@+id/now"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="28dp"/>

    <TextView
        android:id="@+id/nowformatted1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textColor="#FF0000"
        android:textStyle="bold"
        android:textSize="28dp"/>
    <TextView
        android:id="@+id/nowformatted2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textColor="#0000FF"
        android:textStyle="italic"
        android:textSize="28dp"/>
</LinearLayout>

Reference:
- java.util.Date
- java.text.DateFormat
- java.text.SimpleDateFormat

Create SimpleDateFormat for specified Locale

Example of creating SimpleDateFormat with specified Locale from previous exercise "Get default Locale and available Locales".

package com.example.androidlocale;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import android.app.Activity;

public class MainActivity extends Activity {

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  
  TextView textViewDefaultLocale = (TextView)findViewById(R.id.defaultlocale);
  TextView textViewNoOfLocale = (TextView)findViewById(R.id.numberoflocale);
  ListView listViewAvailableLocale = (ListView)findViewById(R.id.listviewlocale);
  
  Locale defaultLocale = Locale.getDefault();
  textViewDefaultLocale.setText("Default Locale: " + defaultLocale.toString());

  final Locale[] availableLocales = Locale.getAvailableLocales();
  textViewNoOfLocale.setText("Number of available Locale: " + availableLocales.length);
  String[] availableLocalesString = new String[availableLocales.length];
  
  for (int i=0; i<availableLocales.length; i++){
   availableLocalesString[i] = availableLocales[i].toString();
  }
  
  ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, 
            android.R.layout.simple_list_item_1, availableLocalesString);
  listViewAvailableLocale.setAdapter(adapter);
  
  listViewAvailableLocale.setOnItemClickListener(
    new OnItemClickListener(){

   @Override
   public void onItemClick(AdapterView<?> parent, 
     View view, int position, long id) {
    Locale item = availableLocales[position];
    
    String format = "yyyy-MM-dd'T'HH:mm:ss.SSSZ";
    SimpleDateFormat simpleDateFormat = new SimpleDateFormat(format, item);
    Date now = new Date();
    Toast.makeText(getApplicationContext(),
      "Locale: " + item.toString() + "\n"
      + simpleDateFormat.format(now),
      Toast.LENGTH_LONG).show();

   }});

 }

}