iphone - MFMailComposeViewController 在一个单独的类中

Question

我试图创建一个可以在多个 iPhone 项目中使用的“实用电子邮件发件人类”。

我为此目的创建了 MailSender header 和实现。

邮件发送器.h:

@interface MailSender : NSObject<MFMailComposeViewControllerDelegate>

- (id) initWithParent:(UIViewController*) mainController;

- (void) invokeMailSender:(NSString*) to:(NSString*) subject:(NSString*) failureTitle:(NSString*) failureMessage:(NSString*) failureCancel;

@end

MailSender.m:

#import "MailSender.h"

@implementation MailSender

MFMailComposeViewController* mailer;
UIViewController* mailParentController;

- (id) initWithParent:(UIViewController*) mainController
{
    if( self = [super init])
    {
      mailParentController = mainController;
    }
    return self;
}

- (void) invokeMailSender:(NSString*) to:(NSString*) subject:(NSString*) failureTitle:(NSString*) failureMessage:(NSString*) failureCancel;

{
    if([MFMailComposeViewController canSendMail])
    {
        mailer = [[MFMailComposeViewController alloc] init];

        mailer.mailComposeDelegate = self;

        [mailer setSubject:subject];

        NSArray *toRecipients = [NSArray arrayWithObjects:to, nil];

        [mailer setToRecipients:toRecipients];
       [mailParentController presentModalViewController:mailer animated:YES];
    }
    else
    {
        UIAlertView* alert = [[UIAlertView alloc] initWithTitle:failureTitle message:failureMessage
                                                       delegate:nil cancelButtonTitle:failureCancel otherButtonTitles: nil];

        [alert show];
    }
}

-(void)mailComposeController:(MFMailComposeViewController *)controller didFinishWithResult:(MFMailComposeResult)result error:(NSError *)error
{
    // Do nothing
    [mailParentController dismissModalViewControllerAnimated:YES];
    mailer = nil;
}



@end

我使用以下指令从 View Controller 调用类(在按钮按下操作中):

@implementation InfoViewController

MailSender *sender;

- (IBAction)openMail:(id)sender
{
    sender = [[MailSender alloc] initWithParent:self];
    [sender invokeMailSender:@"test@test.com" :@"123" :@"123" :@"123" :@"123"];
}

.... 
@end

当我运行代码时，我能够正确显示电子邮件 View 。但是，随后发生崩溃。请注意，直接从我的 UIViewController 使用 MFMailComposeViewController 时我没有崩溃(并将 View Controller 指定为委托(delegate))，

有什么想法吗？对不起，我还是 Objective C 的新手 :)

Answer 1

您需要保留发件人 MailSender 实例。在您调用调用消息后，它正在被释放。

您可以通过声明一个名为sender 的property 来做到这一点。例如

@property (strong, nonatomic) MailSender *sender;
...
@synthesize sender = _sender;
...
self.sender = [[MailSender alloc] initWithParent:self];
[self.sender invokeMailSender:@"noor@dimachk.com" :@"123" :@"123" :@"123" :@"123"];

顺便说一句，你的方法声明有点滑稽。你应该命名参数。例如

- (void)invokeMailSender:(NSString *)sender 
                      to:(NSString *)to 
                 subject:(NSString *)subject 
            failureTitle:(NSString *)failureTitle 
          failureMessage:(NSString *)failureMessage 
failureCancelButtonTitle:(NSString *)failureCancelButtonTitle