Objective c 当我更改图幅iOS 8时，UIViewController视图消失

这段代码在iOS 7上运行得很好，但是当它在XCode 6和iOS8模拟器中运行时，在我对self.webview.frame做了一个小更改之后，视图就会消失（调用UIViewController ViewWillEnglish）。当我从操作表中选择“编辑”选项时，就会发生这种情况。但是，当我点击webView并单击notify/call键盘时，它不会消失。此UIViewController是由rootViewController以modalPresentationStyle:UIModalPresentationFormSheet呈现的。如果有任何帮助，我将不胜感激

- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex{
    NSString *title = [actionSheet buttonTitleAtIndex:buttonIndex];
    if([title isEqualToString:@"Edit"]){
        [self switchModeTo:@"Edit"];
    }
}

- (void)switchModeTo:(NSString *)mode{
    if([mode isEqualToString:@"Edit"]){
        self.isEditMode = YES;
        [self.btnApply setHidden:NO];
        [self.btnMore setHidden:YES];
        CGRect frame = [self.webview frame];
        frame.origin.y = 44;
        frame.size.height = 492;
        [self.webview setFrame:frame];
    }
}

- (void)keyBoardWillShow:(NSNotification *)notif{
    [self switchModeTo:@"Edit"];
}

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我有一个非常类似的问题。我试图呈现从操作表触发的模式视图控制器。模态视图已呈现，然后立即被驳回

我创建了另一个测试用例，并收到以下消息：

Warning: Attempt to present <ModalViewController: 0x78fbadd0>  on <MainViewController: 0x78fa71c0> which is already presenting (null)

- (void)actionSheet:(UIActionSheet *)actionSheet
clickedButtonAtIndex:(NSInteger)buttonIndex
{
    if ( buttonIndex != actionSheet.cancelButtonIndex ) {
        [self performSelector:@selector(showModalView) withObject:nil afterDelay:0.3];
    }
}

- (void)showModalView
{
    ModalViewController* modalVC = [[ModalViewController alloc] init];
    [self presentViewController:modalVC animated:YES completion:nil];
}