Android Example-Count Down Timer Application

activity_main.xml

<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:orientation="vertical">

    <Button
        android:id="@+id/startbutton"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Start"
        android:textAlignment="center"/>

    <TableLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:padding="10dp">

        <TableRow>

            <TextView
                android:id="@+id/timer"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:paddingRight="10dp"
                android:text="Time: "
                android:textSize="20dp" />
        </TableRow>
    </TableLayout>

    <TextView
        android:id="@+id/timeElapsed"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingLeft="10dp"
        android:paddingRight="10dp"
        android:text="Time elapsed: "
        android:textSize="20dp" />

</LinearLayout>

MainActivity.java

package in.kantapp.example18;

import android.os.Bundle;
import android.os.CountDownTimer;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends Activity implements OnClickListener
{

    private santimer timer;
    private Boolean timer_flag=false;
    private final long startTime = 50000;
    private final long interval = 1;
    private Button start;
    private TextView text,time_eplapsed;
    private long timeElapsed;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        start = (Button) findViewById(R.id.startbutton);
        start.setOnClickListener(this);
        text = (TextView) findViewById(R.id.timer);
        time_eplapsed = (TextView) findViewById(R.id.timeElapsed);
        timer = new santimer(startTime, interval);
        text.setText(text.getText() + String.valueOf(startTime));
    }

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        if (!timer_flag) {
            timer.start();
            timer_flag = true;
            start.setText("Start");
        } else {
            timer.cancel();
            timer_flag = false;
            start.setText("Reset");
        }
    }

    private class santimer extends CountDownTimer {

        public santimer(long millisInFuture, long countDownInterval) {
            super(millisInFuture, countDownInterval);
            // TODO Auto-generated constructor stub

        }

        @Override
        public void onFinish() {
            // TODO Auto-generated method stub
            text.setText("Time's up!");
            time_eplapsed.setText("Time Elapsed: " + String.valueOf(startTime));
        }

        @Override
        public void onTick(long millisUntilFinished) {
            // TODO Auto-generated method stub
            text.setText("Time remain:" + millisUntilFinished);
            timeElapsed = startTime - millisUntilFinished;
            time_eplapsed.setText("Time Elapsed: "
                    + String.valueOf(timeElapsed));
        }

    }
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="in.kantapp.example18">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>