countdown timer in android.

Android Count Down Timer Example

In this sample application, we will create a countdown timer in android using the CountDownTimerclass. This is an example of showing a 30-second countdown in a TextView. We will update the TextView on every tick of the timer.The option to stop and restart the timer is also provided.

So let us start,

1.Create a new project File ->New -> Project ->Android ->Android Application Project. While creating the new project, name the activity as TimerActivity(TimerActivity.java) and layout asactivity_timer.xml.

2.Now let us design the UI for the TimerActivity i.e activity_timer.xml with a Textview and a button.
activity_timer.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:background="@drawable/bgi" >

<TextView
android:id="@+id/timer"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:paddingRight="10dip"
android:textSize="50dp" />

<Button
android:id="@+id/button"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:text="Start" />

</RelativeLayout>

3. Now in the TimerActivity, we implement the countdown timer by extending the CountDownTimer class.Press Ctrl+Shift+O for missing imports after typing the code.

TimerActivity.java

public class TimerActivity extends Activity implements OnClickListener {

private CountDownTimer countDownTimer;
private boolean timerHasStarted = false;
private Button startB;
public TextView text;
private final long startTime = 30 * 1000;
private final long interval = 1 * 1000;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_timer);
startB = (Button) this.findViewById(R.id.button);
startB.setOnClickListener(this);
text = (TextView) this.findViewById(R.id.timer);

countDownTimer = new MyCountDownTimer(startTime, interval);
text.setText(text.getText() + String.valueOf(startTime/1000));

}

@Override
public void onClick(View v) {
if (!timerHasStarted) {
countDownTimer.start();
timerHasStarted = true;
startB.setText("STOP");
} else {
countDownTimer.cancel();
timerHasStarted = false;
startB.setText("RESTART");
}
}



public class MyCountDownTimer extends CountDownTimer {
public MyCountDownTimer(long startTime, long interval) {
super(startTime, interval);
}

@Override
public void onFinish() {
text.setText("Time's up!");
}

@Override
public void onTick(long millisUntilFinished) {
text.setText("" + millisUntilFinished/1000);

}
}

}

4.Run the project by right-clicking project Run as android project.

Output:
The output of this example would be similar to the one as follows:
 Count Down Timer

 Count Down Timer

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