How to use Intent.ACTION_TIME_TICK

In one of my applications, it was required to update a TextView every minute. The first approach that I could think of was to have an AsyncTask running a while loop till a minute (check for initial time+60,000 milliseconds in every iteration), but then I found out about ACTION_TIME_TICK broadcast action.

As per java docs:-

public static final String ACTION_TIME_TICK

Broadcast Action: The current time has changed. Sent every minute. You cannot receive this through components declared in manifests, only by explicitly registering for it with Context.registerReceiver().

This is a protected intent that can only be sent by the system.

Note: It is assumed that reader has knowledge of how to create and run a simple android application.

To learn how to use this broadcast action, I made a small program to display the current time (hours and minutes) in the form of a digital clock. The process is as follows:-

1. Create a new Android project, with name DigiClock and package name com.cc.demo.digiClock

Open activity_main.xml and paste the following:

	<?xml version="1.0" encoding="utf-8"?>
	<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:layout_width="wrap_content"
	android:layout_height="fill_parent"
	android:orientation="vertical">
	<!-- Text View to show hour-->
	<TextView
	android:id="@+id/hourText"
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:layout_marginRight="5dp" />
	<!-- Text View to show minute-->
	<TextView
	android:id="@+id/minuteText"
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:layout_toRightOf="@id/hourText" />
	</RelativeLayout>

view raw activity_main.xml hosted with by GitHub

3. Open Activity class(create one if already not created) and paste the following:-

	package com.cc.demo.digiClock;
	import java.util.Calendar;
	import android.app.Activity;
	import android.content.BroadcastReceiver;
	import android.content.Context;
	import android.content.Intent;
	import android.content.IntentFilter;
	import android.os.Bundle;
	import android.widget.TextView;
	public class DigiClockActivity extends Activity {
	private static BroadcastReceiver tickReceiver;
	private TextView hourText;
	private TextView minuteText;
	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState)
	{
	super.onCreate(savedInstanceState);
	setContentView(R.layout.main);
	hourText=(TextView)findViewById(R.id.hourText);
	minuteText=(TextView)findViewById(R.id.minuteText);
	//Set the current time at startup
	hourText.setText(String.valueOf(Calendar.getInstance().get(Calendar.HOUR_OF_DAY)));
	minuteText.setText(String.valueOf(Calendar.getInstance().get(Calendar.MINUTE)));
	//Create a broadcast receiver to handle change in time
	tickReceiver=new BroadcastReceiver(){
	@Override
	public void onReceive(Context context, Intent intent) {
	if(intent.getAction().compareTo(Intent.ACTION_TIME_TICK)==0)
	{
	hourText.setText(String.valueOf(Calendar.getInstance().get(Calendar.HOUR_OF_DAY)));
	minuteText.setText(String.valueOf(Calendar.getInstance().get(Calendar.MINUTE)));
	}
	}
	};
	//Register the broadcast receiver to receive TIME_TICK
	registerReceiver(tickReceiver, new IntentFilter(Intent.ACTION_TIME_TICK));
	}
	@Override
	public void onStop()
	{
	super.onStop();
	//unregister broadcast receiver.
	if(tickReceiver!=null)
	unregisterReceiver(tickReceiver);
	}
	}

view raw MainActivity.java hosted with by GitHub

In the above code, we first create a broadcast receiver object, which will change the text of our TextView when the received action is ACTION_TIME_TICK. After that, we register this broadcast receiver via call to registerReceiver, which calls “tickReceiver” with any broadcast intents that matches “ACTION_TIME_TICK” i.e. the onReceive method of tickReceiver will be called every minute.

Note: Do remember to call the method “unregisterReceiver” or else your application will throw an exception like this:-

“Activity com.cc.demo.digiClock.DigiClockActivity has leaked IntentReceiver com.cc.demo.digiClock.DigiClockActivity$1@412bacb8 that was originally registered here. Are you missing a call to unregisterReceiver()?”

Happy Coding!!