'Application tried to present a nil modal view controller on target' error/crash when trying to open mail composer - iphone

Question

I have a simple app, which opens a modal view to send email. Am using Xcode 4.2 and iOS 5, and am testing with iOS Simulator. The app crashes with
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason:
'Application tried to present a nil modal view controller on target
.'
when executing the line:
[self presentModalViewController:mailComposer animated:YES];
though I have initialized the object 'mailComposer'.
Class com_FirstViewController.m :
#import "com_FirstViewController.h"
...
#implementation com_FirstViewController
....
....
-(void)showEmailComposer {
Class mailClass = (NSClassFromString(#"MFMailComposeViewController"));
if (mailClass != nil)
{
if ([mailClass canSendMail]) {
NSLog(#"showEmailComposer: Calling displayComposerSheet");
[self displayComposerSheet];
} else {
NSLog(#"showEmailComposer: Calling launchMailAppOnDevice");
[self launchMailAppOnDevice];
}
}
else {
NSLog(#"showEmailComposer: Calling launchMailAppOnDevice");
[self launchMailAppOnDevice];
}
}
#pragma mark -
#pragma mark Compose Mail
-(void) displayComposerSheet {
mailComposer = [[MFMessageComposeViewController alloc] init];
mailComposer.messageComposeDelegate = self;
// Set the mail title
[mailComposer setTitle:#"Mail Title"];
// Set the recipients
NSArray *toRecipients = [NSArray arrayWithObject:#"user#company.com"];
[mailComposer setRecipients:toRecipients];
// EMail Body
NSString *mailBody = #"This is the mail body";
[mailComposer setBody:mailBody];
NSLog(#"present the modal view ctlr");
[self presentModalViewController:mailComposer animated:YES];
}
...
...
Any pointers please?

Answer 1

I have also encountered a similar problem. I allocated an instance of MFMailComposeViewController and tried to present it modally. I also got an exception:
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Application tried to present a nil modal view controller on target
This was because the Mail option was disabled in the settings of the iPhone. It can be the case also when no mail account is set up in the device. So the MFMailCompseViewController instance will be nil and presenting it modally will cause the crash.
I used the canSendMail method of the MFMailComposeViewController to get around this issue.
Class mailClass = (NSClassFromString(#"MFMailComposeViewController"));
if (mailClass != nil) {
MFMailComposeViewController * mailView = [[MFMailComposeViewController alloc] init];
mailView.mailComposeDelegate = self;
//Set the subject
[mailView setSubject:emailSubject];
//Set the mail body
[mailView setMessageBody:emailBody isHTML:YES];
//Display Email Composer
if([mailClass canSendMail]) {
[self.navControl presentModalViewController:mailView animated:YES];
}
}

Answer 2

mailComposer = [[MFMessageComposeViewController alloc] init];
is the source of the problem, in my opinion. There's no way the simulator can send SMS messages, so the initializer method may return NULL. Anyways, sou seem to be wanting to send an email, so I'd say you need to use
mailComposer = [[MFMailComposeViewController alloc] init];