ipad-NSThread-Error - ipad

Question

For Check Valid Login,
I Fetch Data From Webservice And To Show Progress ,
I Display UIIndicatorView Inside UIAlertView
Problem Is :
During Progress When Press Home Button Of IPad Device Then My Application Is Close,, And Second Time When I Try To Start App Then (Black Screen Is Display) Apps Is Not Start.
How I Can Solve this problem?
My Code Is:
-(NSMutableString*) getLoginMessage:(NSString*) UserName : (NSString *) Password : (NSString *) url
{
[NSThread detachNewThreadSelector:#selector(showAlertMethod) toTarget:self withObject:nil];
#try
{
NSArray *Keys =[[NSArray alloc] initWithObjects:#"LoginName",#"PassWord",nil];
NSArray *KeyValue =[[NSArray alloc] initWithObjects:UserName,Password,nil];
operationName=[[NSString alloc] init];
operationName =#"ClientLogin";
NSURL *WebServiceUrl=[WebServiceHelper generateWebServiceHTTPGetURL:url : operationName : Keys: KeyValue];
NSXMLParser *parser = [[NSXMLParser alloc] initWithContentsOfURL:WebServiceUrl];
[parser setShouldReportNamespacePrefixes:NO];
[parser setShouldResolveExternalEntities:NO];
[parser setDelegate:self];
[parser parse];
[Keys release];
[KeyValue release];
[WebServiceUrl release];
[NSThread detachNewThreadSelector:#selector(dismissAlertMethod) toTarget:self withObject:nil];
}
#catch (NSException * e)
{
[NSThread detachNewThreadSelector:#selector(dismissAlertMethod) toTarget:self withObject:nil];
}
return Result;
}
-(void)showAlertMethod
{
NSAutoreleasePool *pool1=[[NSAutoreleasePool alloc]init];
progressAlert = [[UIAlertView alloc] initWithTitle:#"Signing in..." message:#"Please wait..." delegate:nil cancelButtonTitle: nil otherButtonTitles:nil];
CGRect alertFrame = progressAlert.frame;
UIActivityIndicatorView* activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
activityIndicator.frame = CGRectMake(135,alertFrame.size.height+75, alertFrame.size.width,30);
activityIndicator.hidden = NO;
activityIndicator.contentMode = UIViewContentModeCenter;
[activityIndicator startAnimating];
[progressAlert addSubview:activityIndicator];
[activityIndicator release];
[progressAlert show];
[pool1 release];
}
-(void)dismissAlertMethod
{
NSAutoreleasePool *pool2=[[NSAutoreleasePool alloc]init];
[progressAlert dismissWithClickedButtonIndex:0 animated:YES];
[pool2 release];
}

Answer 1

A little hard to read your code, but: you cannot do UI from a thread. Your alert must be created and shown from the main thread.