iOS，PopOverPresentationController 问题，.xib

Question

我有一个 NavigationController，另一个控制器被压入它的堆栈：BNRDetailsViewController。现在，在 BNRDetailsViewController 中，我试图在按下工具栏按钮时显示一个弹出窗口，这将向我展示 UIImagePickerController（仅在 iPad 设备上）。因此，我尝试遵循以下 stackoverflow 线程：

UIPopoverPresentationController on iOS 8 iPhone

但没有成功。如果我只使用他们的代码，我会收到一条错误消息，即pushing navigationController is not supported。如果我尝试像这样推送新创建的UIPopoverPresentationController：[self.navigationController pushViewController:self.imagePickerPopover animated:YES]; 它会崩溃，因为UIPopoverPresentationController 不是UIViewController 类型，所以，我想，我不能只是将它推送到堆栈上。

在这种特殊情况下，您建议怎么做？

这是我现在拥有的在按下工具栏按钮时触发的代码：

- (IBAction)takePicture:(id)sender {
UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];

// If the device have camera, take a picture, otherwise,
// just pick from photo library
if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
    imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;
} else {
    imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
}

imagePicker.delegate = self;

// Place image picker on the screen
//[self presentViewController:imagePicker animated:YES completion:NULL];

// Place image picker on the screen
// Check for iPad device before instantiating the popover controller
if ([UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPad) {
    // Create a new popover controller that will display the imagePicker
    _imagePickerPopover = [[UIPopoverPresentationController alloc] initWithPresentedViewController:imagePicker presentingViewController:self];

    imagePicker.preferredContentSize = CGSizeMake(280, 200);
    _imagePickerPopover.delegate = self;
    _imagePickerPopover.sourceView = self.view;
    CGRect frame = [[sender valueForKey:@"view"] frame];
    frame.origin.y = frame.origin.y + 20;
    _imagePickerPopover.sourceRect = frame;
   // [self.navigationController pushViewController:self.imagePickerPopover animated:YES];
}
}

Answer 1

这是基于您的代码的代码，它将使弹出框显示在 iPad 上。

if ([UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPad) {
    imagePicker.modalPresentationStyle = UIModalPresentationPopover;
    imagePicker.preferredContentSize = CGSizeMake(280, 200);
    CGRect frame = [[sender valueForKey:@"view"] frame];
    frame.origin.y = frame.origin.y + 20;

    UIPopoverPresentationController *popoverController = 
        imagePicker.popoverPresentationController;
    popoverController.sourceView = self.view;
    popoverController.sourceRect = frame;

    [self.navigationController presentViewController:imagePicker 
                               animated:YES completion:nil];
}