无法使 UIPopover 以编程方式显示

Question

我希望在应用首次以纵向模式启动时出现弹出窗口，而不是隐藏并要求用户在弹出窗口出现之前点击按钮。我试图通过谷歌和其他 StackOverflow 线程之类的方法找到解决方案，但我无法弄清楚。因此，如果由 XCode 创建的标准 SplitView 示例不同，我将把代码放在下面。如果我可以让它在这个应用程序上运行，我希望我能理解它并能够在其他地方应用它。

我曾想过尝试在按下按钮时调用所调用的内容...但我无法弄清楚调用的内容以及声明的位置...我觉得我忽略了一些基本的东西把我逼疯了！

DetailView 控制器 DetailViewController.h

#import <UIKit/UIKit.h>

@interface DetailViewController : UIViewController <UIPopoverControllerDelegate, UISplitViewControllerDelegate> {

UIPopoverController *popoverController;
UIToolbar *toolbar;

id detailItem;
UILabel *detailDescriptionLabel;
}

@property (nonatomic, retain) IBOutlet UIToolbar *toolbar;

@property (nonatomic, retain) id detailItem;
@property (nonatomic, retain) IBOutlet UILabel *detailDescriptionLabel;

@end

DetailViewController.m

#import "DetailViewController.h"
#import "RootViewController.h"


@interface DetailViewController ()
@property (nonatomic, retain) UIPopoverController *popoverController;
- (void)configureView; 
@end



@implementation DetailViewController

@synthesize toolbar, popoverController, detailItem, detailDescriptionLabel;

#pragma mark -
#pragma mark Managing the detail item

/*
 When setting the detail item, update the view and dismiss the popover controller if             it's showing.
 */
- (void)setDetailItem:(id)newDetailItem {
    if (detailItem != newDetailItem) {
        [detailItem release];
        detailItem = [newDetailItem retain];

        // Update the view.
        [self configureView];
    }

    if (self.popoverController != nil) {
        [self.popoverController dismissPopoverAnimated:YES];
    }        
}


- (void)configureView {
    // Update the user interface for the detail item.
    detailDescriptionLabel.text = [detailItem description];   
}


#pragma mark -
#pragma mark Split view support

- (void)splitViewController: (UISplitViewController*)svc willHideViewController:(UIViewController *)aViewController withBarButtonItem:(UIBarButtonItem*)barButtonItem forPopoverController: (UIPopoverController*)pc {

barButtonItem.title = @"Root List";
NSMutableArray *items = [[toolbar items] mutableCopy];
[items insertObject:barButtonItem atIndex:0];
[toolbar setItems:items animated:YES];
[items release];
self.popoverController = pc;
}


// Called when the view is shown again in the split view, invalidating the button and popover controller.
- (void)splitViewController: (UISplitViewController*)svc willShowViewController:(UIViewController *)aViewController invalidatingBarButtonItem:(UIBarButtonItem *)barButtonItem {

NSMutableArray *items = [[toolbar items] mutableCopy];
[items removeObjectAtIndex:0];
[toolbar setItems:items animated:YES];
[items release];
self.popoverController = nil;
}


#pragma mark -
#pragma mark Rotation support

// Ensure that the view controller supports rotation and that the split view can therefore show in both portrait and landscape.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
return YES;
}


#pragma mark -
#pragma mark View lifecycle

/*
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
[super viewDidLoad];
}
*/

/*
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
}
*/
/*
- (void)viewDidAppear:(BOOL)animated {
 [super viewDidAppear:animated]; 
}
*/
/*
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
}
*/
/*
- (void)viewDidDisappear:(BOOL)animated {
[super viewDidDisappear:animated];
}
*/

- (void)viewDidUnload {
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
self.popoverController = nil;
}


#pragma mark -
#pragma mark Memory management

/*
- (void)didReceiveMemoryWarning {
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];

// Release any cached data, images, etc that aren't in use.
}
*/

- (void)dealloc {
[popoverController release];
[toolbar release];

[detailItem release];
[detailDescriptionLabel release];
[super dealloc];
}

@end

rootview 是一个典型的 UITableViewController 并没有什么特别的，但如果出于某种原因您需要它或委托（这很无聊减去加载视图）来帮助我解决这个问题，我发布这些也没有问题。当我告诉它我想为 iPad 创建一个拆分视图并且我没有修改它时，这也是 XCode 生成的直接内容。

希望我忽略了一些非常小的事情，它会让我拍脑袋说“我不敢相信我错过了！”感谢您的帮助。

Answer 1

想通了！

我放了

[self.popoverController presentPopoverFromBarButtonItem:[[toolbar items] objectAtIndex:0] permittedArrowDirections:UIPopoverArrowDirectionUp animated:YES];

在 ViewDidLoad 方法中。我知道这很简单！它似乎没有任何问题！