Introduction

In this article, I explain the time and date classes in Android, how to use the Date and Time Classes in Android and how to work with these classes. You can easily understand it using the following instructions.
Step 1
As usual, create a new project file as in the following.
newTimeUpdater.jpg
Step 2
Open the "activity_main.xml" file and update it with the following code:
  1. <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  2. xmlns:tools="http://schemas.android.com/tools"
  3. android:layout_width="match_parent"
  4. android:layout_height="match_parent"
  5. android:paddingBottom="@dimen/activity_vertical_margin"
  6. android:paddingLeft="@dimen/activity_horizontal_margin"
  7. android:paddingRight="@dimen/activity_horizontal_margin"
  8. android:paddingTop="@dimen/activity_vertical_margin"
  9. tools:context=".MainActivity" >
  10. <Button
  11. android:id="@+id/button1"
  12. android:layout_width="wrap_content"
  13. android:layout_height="wrap_content"
  14. android:layout_alignParentLeft="true"
  15. android:layout_alignParentRight="true"
  16. android:text="@string/update_btn" />
  17. </RelativeLayout>
Step 3
Open the "MainActivity.java" file and update it with the following code:
  1. package com.example.androidthirdapp;
  2. import java.util.Date;
  3. import android.app.Activity;
  4. import android.os.Bundle;
  5. import android.view.Menu;
  6. import android.view.View;
  7. import android.widget.Button;
  8. public class MainActivity extends Activity {
  9. Button btn;
  10. @Override
  11. protected void onCreate(Bundle savedInstanceState) {
  12. super.onCreate(savedInstanceState);
  13. setContentView(R.layout.activity_main);
  14. btn = (Button) findViewById(R.id.button1);
  15. //Onclick listener
  16. btn.setOnClickListener(new View.OnClickListener() {
  17. //Onclick method
  18. public void onClick(View v) {
  19. //Call updateTime() when button is clicked
  20. updateTime();
  21. }
  22. });
  23. }
  24. //Method definition starts here with no return type
  25. public void updateTime() {
  26. //Setting button text with current time
  27. //java.util.Date() method is used to get the current time
  28. btn.setText(new Date().toString());
  29. }
  30. @Override
  31. public boolean onCreateOptionsMenu(Menu menu) {
  32. // Inflate the menu; this adds items to the action bar if it is present.
  33. getMenuInflater().inflate(R.menu.main, menu);
  34. return true;
  35. }
  36. }
Step 4
Now create a new Java file named "CurrentTimeActivity.java" and use the following code in it:
  1. package com.example.androidthirdapp;
  2. import java.util.Date;
  3. import android.app.Activity;
  4. import android.os.Bundle;
  5. import android.view.View;
  6. import android.widget.Button;
  7. public class CurrentTimeActivity extends Activity {
  8. Button btn;
  9. public void onCreate(Bundle savedInstanceState) {
  10. super.onCreate(savedInstanceState);
  11. setContentView(R.layout.activity_main);
  12. btn = (Button) findViewById(R.id.button1);
  13. updateTime();
  14. btn.setOnClickListener(new View.OnClickListener() {
  15. public void onClick(View v) {
  16. updateTime();
  17. }
  18. });
  19. }
  20. //Method definition starts here with no return type
  21. public void updateTime() {
  22. //Setting button text with current time
  23. //java.util.Date() method is used to get the current time
  24. btn.setText(new Date().toString());
  25. }
  26. }
Step 5
Open the "AndroidManifest.xml" file and update it with the following code:
  1. <?xml version="1.0" encoding="utf-8"?>
  2. <manifest xmlns:android="http://schemas.android.com/apk/res/android"
  3. package="com.example.androidthirdapp"
  4. android:versionCode="1"
  5. android:versionName="1.0" >
  6. <uses-sdk
  7. android:minSdkVersion="8"
  8. android:targetSdkVersion="17" />
  9. <application
  10. android:allowBackup="true"
  11. android:icon="@drawable/ic_launcher"
  12. android:label="@string/app_name"
  13. android:theme="@style/AppTheme" >
  14. <activity
  15. android:name="com.example.androidthirdapp.MainActivity"
  16. android:label="@string/app_name" >
  17. <intent-filter>
  18. <action android:name="android.intent.action.MAIN" />
  19. <category android:name="android.intent.category.LAUNCHER" />
  20. </intent-filter>
  21. </activity>
  22. </application>
  23. </manifest>
Step 6
See the output.
Update Button
updateTime.jpg
Current Time
currentTim.jpg