Count Down Functionality

Count Down is an act of counting numerals in reverse order to zero, especially before the launching of a rocket or missile.

Example

This example demostrate about how to integrate Android Count Down.

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/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" >
   </Button>
   <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>

Step 3 − Add the following code to src/MainActivity.java

package myapplication.example.com.myapplication;

import android.os.Bundle;
import android.os.CountDownTimer;
import android.app.Activity;
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 = 1000;
   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)); 
      } 
   }
}

Step 4 − No need to changemanifest.java

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click Run icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen −