objective-c – 应用程序在IOS7中的MFMailComposeViewController对象上崩溃

MFMailComposeViewController *picker = [[MFMailComposeViewController alloc] init];

您应该检查MFMailComposeViewController是否能够在尝试发送之前发送您的邮件(例如,用户在iOS设备上没有任何邮件帐户).

在您的Objective-C案例中：

MFMailComposeViewController *myMailCompose = [[MFMailComposeViewController alloc] init];

if ([MFMailComposeViewController canSendMail]) {
    myMailCompose.mailComposeDelegate = self;
    [myMailCompose setSubject:@"Subject"];
    [myMailCompose setMessageBody:@"message" isHTML:NO];
    [self presentViewController:myMailCompose animated:YES completion:nil];
} else {
    // unable to send mail,notify your users somehow
}

斯威夫特3：

let myMailCompose = MFMailComposeViewController()

if MFMailComposeViewController.canSendMail() {
    myMailCompose.mailComposeDelegate = self
    myMailCompose.setSubject("Subject")
    myMailCompose.setMessageBody("message",isHTML: false)
    self.present(myMailCompose,animated: true,completion: nil)
} else {
    // unable to send mail,notify your users somehow
}