Countdown Timer Example Application (Android)

We'll create a sample application Countdown Timer in android using CountDownTimer class. This application will accept duration for countdown in second and display the running timer with the interval of 1/10th of second. You can stop the timer and restart once again with same input or with updated input.

Output Screen:

 

We need to create:

• Activity 
• MainActivity.java: contains java file and xml layout file
• MainActivity.java
• activity_main.xml

Source Codes:  

activity_main.xml

 
 <RelativeLayout 
     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:paddingBottom="@dimen/activity_vertical_margin"
     android:paddingLeft="@dimen/activity_horizontal_margin"
     android:paddingRight="@dimen/activity_horizontal_margin" 
     android:paddingTop="@dimen/activity_vertical_margin" 
     tools:context=".MainActivity">   

     <TextView
         android:id="@+id/tvHeader"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_centerHorizontal="true"
         android:layout_marginTop="20dp"
         android:text="@string/countdown_timer"
         android:textSize="24sp"/>

     <LinearLayout
         android:id="@+id/llSetTimer"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_below="@+id/tvHeader"
         android:layout_centerHorizontal="true"
         android:layout_marginTop="30dp"
         android:orientation="horizontal">

         <EditText
             android:id="@+id/edtSetTimer"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:hint="@string/initialTime"
             android:inputType="number"
             android:textSize="40sp"
             android:maxLength="4"
             android:gravity="end"/>

         <TextView
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:text="@string/second"
             android:textSize="20sp" />
 
     </LinearLayout>
 
     <TextView
         android:id="@+id/tvRemainingTime"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_below="@id/llSetTimer"
         android:layout_centerHorizontal="true"
         android:layout_marginTop="30dp"
         android:text="@string/time_remaining"
         android:textSize="24sp"/>

     <LinearLayout
         android:id="@+id/llRemainingTime"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_below="@id/tvRemainingTime"
         android:layout_centerHorizontal="true"
         android:layout_marginTop="10dp"
         android:orientation="horizontal">

         <TextView
             android:id="@+id/tvSecond"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:text="@string/initialTime"
             android:textSize="60sp"/>
 
         <TextView
             android:id="@+id/tvSeparator"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_marginLeft="4dp"
             android:layout_marginRight="4dp"
             android:text="@string/timeSeparator"
             android:textSize="60sp"/>

         <TextView
             android:id="@+id/tvMilliSecond"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:text="@string/initialTime"
             android:textSize="60sp"/>
 
     </LinearLayout>
 
     <TextView
         android:id="@+id/tvTimeUp"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_below="@id/llRemainingTime"
         android:layout_marginTop="10dp"
         android:layout_centerHorizontal="true"
         android:textSize="30sp"
         android:text="@string/timeUp"
         android:visibility="invisible"/>
 
     <Button
         android:id="@+id/btnStart"
         android:layout_width="200dp"
         android:layout_height="80dp"
         android:layout_below="@+id/tvTimeUp"
         android:layout_centerHorizontal="true"
         android:layout_marginTop="20dp"
         android:text="Start"
         android:textSize="20sp"/>
 
 </RelativeLayout>
 

MainActivity.java

 package com.sonevalley.sushil.countdowntimer;

 import android.os.Bundle;
 import android.os.CountDownTimer;
 import android.support.v7.app.AppCompatActivity;
 import android.text.Editable;
 import android.text.TextWatcher;
 import android.util.Log;
 import android.view.View;
 import android.widget.Button;
 import android.widget.EditText;
 import android.widget.TextView;

 public class MainActivity extends AppCompatActivity implements View.OnClickListener {

     EditText edtSetTimer;
     TextView tvSecond;
     TextView tvMilliSecond;
     TextView tvTimeUp;
     Button btnStart;
     CountDownTimer countDownTimer;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         edtSetTimer = (EditText) findViewById(R.id.edtSetTimer);
         tvSecond = (TextView) findViewById(R.id.tvSecond);
         tvMilliSecond = (TextView) findViewById(R.id.tvMilliSecond);
         tvTimeUp = (TextView) findViewById(R.id.tvTimeUp);
         btnStart = (Button) findViewById(R.id.btnStart);
         btnStart.setOnClickListener(this);

         edtSetTimer.addTextChangedListener(new TextWatcher() {
             @Override
             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
             }
             @Override
             public void onTextChanged(CharSequence s, int start, int before, int count) {

                 String sec = edtSetTimer.getText().toString();
                 if (sec != null && sec != "" && sec.length() > 0) {
                     tvSecond.setText(edtSetTimer.getText());
                     tvMilliSecond.setText("0");
                     tvTimeUp.setVisibility(View.INVISIBLE);                    
                     tvSecond.setText("0");
                 }
             }
             @Override
             public void afterTextChanged(Editable s) {
             }
         });
     }

     @Override
     public void onClick(View v) {
         if (edtSetTimer.getText().toString().trim().length() != 0) {
             int startTime = Integer.parseInt(edtSetTimer.getText().toString()) * 1000;
             Log.i("startTime", startTime + btnStart.getText().toString());
             if (v == btnStart && startTime > 0) {
                 if (btnStart.getText().toString().equalsIgnoreCase("START")) {
                     Log.i("startTime Start", btnStart.getText().toString());
                     countDownTimer = new MyCountDownTimer(startTime, 10);
                     btnStart.setText("STOP");
                     tvTimeUp.setVisibility(View.INVISIBLE);
                     edtSetTimer.setEnabled(false);
                     countDownTimer.start();
                 } else {
                     Log.i("startTime Stop", btnStart.getText().toString());
                     btnStart.setText("START");
                     edtSetTimer.setEnabled(true);
                     countDownTimer.cancel();
                 }
             }
         }
     }

     class MyCountDownTimer extends CountDownTimer {

         public MyCountDownTimer(long millisInFuture, long countDownInterval) {
             super(millisInFuture, countDownInterval);
         }
         @Override
         public void onTick(long millisUntilFinished) {
             long milliSecond = millisUntilFinished % 1000;
             tvMilliSecond.setText(String.valueOf(milliSecond / 100));
             long second = millisUntilFinished / 1000;
             tvSecond.setText(String.valueOf(second));
         }
         @Override
         public void onFinish() {
             btnStart.setText("START");
             edtSetTimer.setEnabled(true);
             tvTimeUp.setVisibility(View.VISIBLE);
         }
     }
 }

Reference

http://developer.android.com/reference/android/os/CountDownTimer.html

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