模态视图控制器关闭时应用程序崩溃

Question

我想从应用程序的第二个屏幕显示modalViewController，当我关闭控制器时，它应该导航到第一个屏幕。下面的代码在 iPhone 4、5 和 iPod Touch 中运行良好，但在 iPAD 中却不行。目标是当我关闭modalViewController 时，它不应该返回到第二个屏幕，而是应该显示第一个屏幕。

        ShareEmail *shareEmail = [[ShareEmail alloc] initWithNibName:[NSString stringWithFormat:@"%@",xibShareEmail] bundle:nil];

        shareEmail.fromWer = @"ownPer";
        [self presentModalViewController:shareEmail animated:NO];
        [shareEmail release];

        [self.navigationController popToViewController:[self.navigationController.viewControllers objectAtIndex:1] animated:YES];

在共享电子邮件类中

[self dismissModalViewControllerAnimated:YES];

Answer 1

您需要保留您的 shareEmail 视图控制器 - 制作一个合成的保留属性

YourClass.h：

@property (nonatomic, retain) ShareEmail *shareEmailViewController;

YourClass.m：

@synthesize shareEmailViewController;

然后通过以下方式显示您的模态视图控制器：

ShareEmail *shareEmail = [[ShareEmail alloc] initWithNibName:[NSString stringWithFormat:@"%@",xibShareEmail] bundle:nil];
self.shareEmailViewController = shareEmail;
[self presentModalViewController:shareEmail animated:NO];
[shareEmail release];

保留的属性将防止视图控制器在使用时被释放。然后，当您稍后将其关闭时，您可以这样做：

[self.shareEmailViewController dismissModalViewControllerAnimated:YES];
self.shareEmailViewController = nil;

这将在你完成后释放保留的属性并释放内存。

Answer 2

有趣的事情正在发生。您正在展示来自self 的视图控制器，然后您让navigationController 执行其向后导航。此时，我之前所说的self 消失了。

从您的presentViewController 方法中删除popViewController 方法。

此外，您还需要使用^completion 处理程序方法。这就是你应该放置导航控制器pop 代码的地方。

-(void)present {
    ShareEmail *email = [[ShareEmail...
    //You'll need to get a weak reference to `self` in `email`
    email.modalDelegate = self; //you need to make a property in ShareEmail
    [self presentViewController:email animated:YES completion:nil];
    [email release];
}

-(void)dismiss {
    [self dismissViewControllerAnimated:YES completion:nil];
    [self.navigationController popToViewController:[self.navigationController.viewControllers objectAtIndex:1] animated:YES];
}

//in ShareEmail.m
[modalDelegate dismiss];