未显示子类 UIViewController

Posted 2023-02-26

【中文标题】未显示子类 UIViewController

【英文标题】：Subclassed UIViewController not shown

【发布时间】：2012-02-20 16:16:25

【问题描述】：

我对 UIViewController 类进行了子类化，如下面的代码所示。 下面编码的视图控制器由 Storyboard 在 TabBarController 中实例化，但未显示其视图（我使用 Interface Builder 添加的标签、工具栏）。唯一显示的项目是 TabBarControllers 选项卡栏。

.h:

@interface FinstatViewController : UIViewController <SplitViewBarButtonItemPresenter,UISplitViewControllerDelegate>
@property (nonatomic, strong) UIBarButtonItem *splitViewBarButtonItem;
@property (weak, nonatomic) IBOutlet UINavigationBar *toolbar;
@end

.m:

#import "FinstatViewController.h"

@interface FinstatViewController ()

@end

@implementation FinstatViewController
@synthesize splitViewBarButtonItem = _splitViewBarButtonItem;   // implementation of SplitViewBarButtonItemPresenter protocol

@synthesize toolbar = _toolbar;                                 // to put splitViewBarButtonItem in

- (void)setSplitViewBarButtonItem:(UIBarButtonItem *)splitViewBarButtonItem

    if (splitViewBarButtonItem != _splitViewBarButtonItem) 
        NSMutableArray *toolbarItems = [self.toolbar.items mutableCopy];
        if (_splitViewBarButtonItem) [toolbarItems removeObject:_splitViewBarButtonItem];
        if (splitViewBarButtonItem) [toolbarItems insertObject:splitViewBarButtonItem atIndex:0];
        self.toolbar.items = toolbarItems;
        _splitViewBarButtonItem = splitViewBarButtonItem;
    


- (void)awakeFromNib  // always try to be the split view's delegate

    [super awakeFromNib];
    self.splitViewController.delegate = self;



- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil

    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) 
        // Custom initialization
    
    return self;


- (void)loadView

    // If you create your views manually, you MUST override this method and use it to create your views.
    // If you use Interface Builder to create your views, then you must NOT override this method.


- (void)viewDidLoad

    [super viewDidLoad];
    //self.splitViewController.delegate=self;
    // Do any additional setup after loading the view, typically from a nib.


- (void)viewDidUnload

    [self setToolbar:nil];
    [super viewDidUnload];
    // Release any retained subviews of the main view.


- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation

    return YES; // (interfaceOrientation == UIInterfaceOrientationPortrait);


@end

我做错了什么？

谢谢！

【参考方案1】：

阅读该方法的注释，然后彻底删除该方法：

- (void)loadView

    // If you create your views manually, you MUST override this method and use it to create your views.
    // If you use Interface Builder to create your views, then you must NOT override this method.

您根本没有视图（即 self.view），因为您没有创建视图，因此您的 viewController 显示为空。当您想在代码中创建视图时，您可以使用- loadView。但是你使用故事板来创建你的视图，所以你不能使用- loadView

这不是你的错，怪苹果。 Xcode 4.3 UIViewController 模板已更新。 当您取消选中“使用 XIB 用于用户界面”时，Apple 的一些聪明人认为您想在代码中创建您的视图。他可能完全错过了故事板公告。

删除该部分后，请考虑在http://bugreport.apple.com/ 提交错误

编辑：此错误已在 Xcode 4.3.2 中修复。该模板不再包含- (void)loadView

【讨论】：

谢谢你，马蒂亚斯。你的回答对我帮助很大！