Execute async method in Application Launching - windows-phone-7

Question

I try to realise logging in my application. And I need login before page starts loading because when all is ok I go to secondpage, and if not to firstpage. To do this I set WMAppManifest like this:
<DefaultTask Name="_default" NavigationPage="" />
And when i execute my async method , paralel application start load page but it is empty and so my application freezes.
How look my Application_Launching:
private async void Application_Launching(object sender, LaunchingEventArgs e)
{
bool logged = await LogIn("login", "pass");
Uri nUri = null;
if (logged)
{
nUri = new Uri("/SecondPage.xaml", UriKind.Relative);
}
else
{
nUri = new Uri("/FirstPage.xaml", UriKind.Relative);
}
((App)Application.Current).RootFrame.Navigate(nUri);
}
async method LogIn:
private async Task<bool> LogIn(string login, string password)
{
string str_login_number = login;
string str_login_pass = password;
JObject jo = new JObject();
jo.Add("number", str_login_number);
jo.Add("pass", str_login_pass);
JsonWorker jWorker = new JsonWorker();
var response = await jWorker.sendJSON("url", jo);
string str_responseformjson = await jWorker.getJSON(response);
jo = JObject.Parse(str_responseformjson);
if (jo["response"].ToString().Equals("ok"))
{
return true;
}
else
{
return false;
}
}
This is code of my class JsonWorker:
class JsonWorker
{
public async Task<HttpWebResponse> sendJSON(string requestUrl, JObject jsonObjesct)
{
HttpWebRequest request = (HttpWebRequest) WebRequest.Create(requestUrl);
request.ContentType = "text/plain; charset=utf-8";
request.Method = "POST";
byte[] jsonAsBytes = Encoding.UTF8.GetBytes(jsonObjesct.ToString());
Stream x = await request.GetRequestStreamAsync();
await x.WriteAsync(jsonAsBytes, 0, jsonAsBytes.Length);
x.Close();
HttpWebResponse response = (HttpWebResponse)(await request.GetResponseAsync());
return response;
}
public async Task<string> getJSON(
HttpWebResponse response)
{
var stream = response.GetResponseStream();
var sr = new StreamReader(stream);
string str_responsefromjson = await sr.ReadToEndAsync();
sr.Close();
stream.Close();
return str_responsefromjson;
}
}
Plese help.

Answer 1

I have the some workflow in one of my apps. I solved this by using a custom UriMapper. Read this Stackoverflow answer for more info.
Here's is the basics.
The UriMapper handles which page to navigate to based on if the user has already entered correct login credentials. Your Activated and Launching events in the app will always Login if proper credentials have been given before.
private void Application_Launching(object sender, LaunchingEventArgs e)
{
RootFrame.UriMapper = new LoginUriMapper();
if (AppSettings.HasLoginInfo)
{
Login();
}
}
private void Application_Activated(object sender, ActivatedEventArgs e)
{
if (e.IsApplicationInstancePreserved == false)
{
// tombstoned! Need to restore state
RootFrame.UriMapper = new LoginUriMapper();
if (AppSettings.NotLoggedIn)
{
Login();
}
}
}
Your MainPage will handle logic if the login fails and then navigate backwards to a login page. When you navigate to the login page always remember to remove any entries from the navigation stack
protected override void OnNavigatedTo(NavigationEventArgs e)
{
base.OnNavigatedTo(e);
while(NavigationService.CanGoBack)
{
NavigationService.RemoveBackEntry();
}
}