Tag Archives: Developer Console

When do Android users install games and why should developers care?

When publishing or updating an Android app it appears in the “just in” list of most recent apps. Potential users browse this list and submitting a new app can result in some thousand initial installations – even if only a few users install it afterwards. To maximize the number of initial installations it is important to submit an app when most potential users are active but the fewest number of apps get deployed by other developers.

I already looked at the time games are published in the Android Market. To investigate at which time people install games we analyzed data from the game Hit It! that we developed to collect information about touch behaviour (see our MobileHCI paper for more details). We first published Hit It! in the Android Market on October 31, 2010. Until April 8, 2011 the game was installed 195,988 times according to the Android Developer Console. The first version that records the time the game is played and started was published as an update on December 18, 2010. We received data about the starting times from 164,161 installations but only use the data received after the 20th of December from 157,438 installations.

For each day of the week and for each hour of the day we computed how many installations were started for the first time. Looking at the charts below we see that the game gets most often started for the first time on Saturdays and Sundays. The most active hours of the day are around shortly before midnight GMT. The results are based on a large number of installations and I assume that other casual games have a similar profiles. We do not measure when the game is installed but when the game is started for the first time but we, however, assume that the first start of the game strongly correlates with the time it is installed.

The data collected from Hit It! can be combined with the statistics of our observation of the Android Market. We simple divide the number of started games by the number of deployed apps. The average over the day is shown in the diagram below. The peak is between 23 o’clock and 5 o’clock. That means that three times more games per deployed game get started at this time compared to 13 o’clock. Taking also the day of the week into account it might be expect to get 4 times more installations from being listed as a most recent app on Sunday evening compared to Tuesday noon (all GMT). As the absolute number of players is higher in the evening than in the morning we conclude that the best time to deploy a game in the Android Market is on Sunday evening GMT.

We will also publish our results in a poster that has been accepted at MobileHCI 2011.

cURLing Android Market stats in my website

Last week I thought it would be nice to collect some statistics about my apps in the Android Market. Seeing Websites like androlib.com and androidpit.de I thought it shouldn’t be a problem. However, apart from strazzere.com I haven’t found much useful information. Since I’m only interested in the stats of my own apps I took a deeper look on Google’s Developer Console for the Android Market.

I played a bit with Firebug and learned that the Developer Console is a GWT application, that JSON is used to get the app descriptions from the server, and that the GWT stuff is horrible to reverse engineer. Luckily I found a post that shows how to get the stats from the Android Marketplace with PHP/cURL. It didn’t worked for me at first but after toying around a bit it works now for me. However, I still have no clue what the JSON stuff I get from the GWT server means and I’m only guessing the most important values. It will likely break when I change anything in my developer account.

Below is the PHP script I use to fetch the data from the developer console. 99% is copied from Craige Thomas (I have absolutely no clue about PHP or cURL!). I only added the part that guesses the position of the values and the caching. The script is used to produce the output of the widget on the right.

60)) {

	//do google authorization

	$data = array('accountType' => 'GOOGLE',
	'Passwd' => 'YOUR PASSWORD',

	$ch = curl_init();
	curl_setopt($ch, CURLOPT_URL, "https://www.google.com/accounts/ClientLogin");
	curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
	curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
	curl_setopt($ch, CURLOPT_POST, true);
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
	curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

	$output = curl_exec($ch);

	$info = curl_getinfo($ch);

	//grab the AUTH token for later

	$auth = '';
	if($info['http_code'] == 200) {
		preg_match('/Auth=(.*)/', $output, $matches);

		if(isset($matches[1])) {
			$auth = $matches[1];

	//login to Android Market
	//this results in a 302
	//I think this is necessary for a cookie to be set

	$ch = curl_init ("http://market.android.com/publish?auth=$auth");
	curl_setopt($ch, CURLOPT_COOKIEJAR, 'cookies.txt');
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
	$output = curl_exec($ch);

	//go to the Developer Console
	$ch = curl_init ("http://market.android.com/publish/Home");
	curl_setopt($ch, CURLOPT_COOKIEFILE, $ckfile);
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
	curl_setopt($ch, CURLOPT_COOKIEJAR, 'cookies.txt');
	$output = curl_exec($ch);

	//grab the JSON data
	$perm = "746E1BE622B08CBF950F619C16FCFF1E";
	$headers = array(
		"Host: market.android.com",
		"User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv: Gecko/20100316 Firefox/3.6.2",
		"Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
		"Accept-Language: de-de,de;q=0.8,en-us;q=0.5,en;q=0.3",
		"Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7",
		"Keep-Alive: 115",
		"Connection: keep-alive",
		"Content-Type: text/x-gwt-rpc; charset=utf-8",
		"X-GWT-Permutation: $perm",
		"X-GWT-Module-Base: http://market.android.com/publish/gwt/",
		"Referer: http://market.android.com/publish/gwt/$perm.cache.html");

	//not sure what x-gwt-permutation means, I think it may have to do with which version of GWT they serve based on your browser

//Change here?
	$postdata = "5|0|4|http://market.android.com/publish/gwt/|14E1D06A04411C8FE46E62317C1AF191|com.google.wireless.android.vending.developer.shared.AppEditorService|getFullAssetInfosForUser|1|2|3|4|0|";

	$ch = curl_init ("http://market.android.com/publish/editapp");
	curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
	curl_setopt($ch, CURLOPT_POST, 1);
	curl_setopt($ch, CURLOPT_POSTFIELDS, $postdata);
	curl_setopt($ch, CURLOPT_COOKIEFILE, 'cookies.txt');
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

	$output = curl_exec($ch);
	$output = substr($output,4);

	$json = json_decode($output);
	$csv = explode(',',$output);

	$apps = array();

	$index = 0;
	$app_count = 0;
	for($i = 0; $i < sizeof($csv); ++$i) {
		if (is_array($json[$i])) {
		if (strpos($csv[$i], ".") !== false) {
			if ($index==1) $apps[$app_count][comments]=$csv[$i];
			else if ($index==2) $apps[$app_count][rating]=$csv[$i];
			else if ($index==4) $apps[$app_count][installs]=$csv[$i];
			else if ($index==6) $apps[$app_count][total]=$csv[$i];
			if ($index==7) {
	for($i = 4; $i < sizeof($innerArray); ++$i) {
		if ((substr($innerArray[$i],-1)=='k') && (substr($innerArray[$i-2],0,17)=='GetImage?imageId=')){

	$Handle = fopen('market_stats.txt', 'w');
	fwrite($Handle, '');
	for($i = 0; $i < sizeof($apps); $i++) {
		fwrite($Handle, "");
	fwrite($Handle, '
"); fwrite($Handle, ''); fwrite($Handle, ""); fwrite($Handle, ''); fwrite($Handle, $apps[$i][name].'
'); fwrite($Handle, 'Total installs '.round($apps[$i][total])); fwrite($Handle, "
'); fclose($Handle); $Handle = fopen('market_stats_history.txt', 'a'); for($i = 0; $i < sizeof($apps); $i++) { fwrite($Handle, $apps[$i][package].', '); fwrite($Handle, round($apps[$i][total]).', '); fwrite($Handle, time()); fwrite($Handle, "\n"); } fclose($Handle); } $readHandle = fopen('market_stats.txt', 'r'); echo fread($readHandle, filesize('market_stats.txt')); fclose($readHandle); ?>