从Play商店Xamarin获取最新的应用程序版本

Question

How can I get latest android app version from Google play store? Earlier to used to do so by using below code

using (var webClient = new System.Net.WebClient())
{
    var searchString = "itemprop=\"softwareVersion\">";
    var endString = "</";
    //possible network error if phone gets disconnected
    string jsonString = webClient.DownloadString(PlayStoreUrl);
    var pos = jsonString.IndexOf(searchString, StringComparison.InvariantCultureIgnoreCase) + searchString.Length;
    var endPos = jsonString.IndexOf(endString, pos, StringComparison.Ordinal);
    appStoreversion = Convert.ToDouble(jsonString.Substring(pos, endPos - pos).Trim());
    System.Diagnostics.Debug.WriteLine($"{currentVersion} :: {appStoreversion}");
    System.Diagnostics.Debug.WriteLine($"{appStoreversion > currentVersion}");
    if ((appStoreversion.ToString() != currentVersion.ToString() && (appStoreversion > currentVersion)))
    {
        IsUpdateRequired = true;
    }
}

& the code below even throwing exception

  var document = 
    Jsoup.Connect("https://play.google.com/store/apps/details?id=" + "com.spp.in.spp" + "&hl=en")
    .Timeout(30000)
    .UserAgent("Mozilla/5.0 (Windows; U; WindowsNT 5.1; en-US; rv1.8.1.6) Gecko/20070725 Firefox/2.0.0.6")
    .Referrer("http://www.google.com")
    .Get();

Eception:

Android.OS.NetworkOnMainThreadException: Exception of type 'Android.OS.NetworkOnMainThreadException' was thrown. at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw ()

But now Play store seems to change few conditions, so existing functionality is broke down. Few similar threads are already available here however those seems to have outdated.

Answer 1

This will return a string-based version, at least until Google changes the html page contents again.

var version = await Task.Run(async () =>
{
    var uri = new Uri($"https://play.google.com/store/apps/details?id={PackageName}&hl=en");
    using (var client = new HttpClient())
    using (var request = new HttpRequestMessage(HttpMethod.Get, uri))
    {
      request.Headers.TryAddWithoutValidation("Accept", "text/html");
      request.Headers.TryAddWithoutValidation("User-Agent", "Mozilla/5.0 (Windows NT 6.2; WOW64; rv:19.0) Gecko/20100101 Firefox/19.0");
      request.Headers.TryAddWithoutValidation("Accept-Charset", "ISO-8859-1");
      using (var response = await client.SendAsync(request).ConfigureAwait(false))
      {
            try
            {
                response.EnsureSuccessStatusCode();
                var responseHTML = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
                var rx = new Regex(@"(?<=""htlgb"">)(\d{1,3}\.\d{1,3}\.{0,1}\d{0,3})(?=<\/span>)", RegexOptions.Compiled);
                MatchCollection matches = rx.Matches(responseHTML);
                return matches.Count > 0 ? matches[0].Value : "Unknown";
            }
            catch
            {
                return "Error";
            }
          }
      }
   }
);
Console.WriteLine(version);

Answer 2

Based from this link , this exception is thrown when an application attempts to perform a networking operation on its main thread. You may refer with this thread wherein it stated that network operations on Android need to be performed off the main UI thread. The easiest way is use a Task to push it onto a thread in the default threadpool.