我最近一直在问有关 UIToolbars 的问题，但现在我发现我需要以编程方式向它添加项目，我已经看到其他人的方法如何去做，但是当我尝试做同样的事情时事情，最终什么也没有出现。查明这个问题是我需要帮助的。这是我在 IB 中的联系方式:

相关代码如下:

头文件:

#import <UIKit/UIKit.h>

@interface ParkingRootViewController : UIViewController {
    UINavigationController *navigationController;
    UIToolbar *toolbar;
    UIBarButtonItem *lastUpdateLabel;
}

@property(nonatomic, retain) IBOutlet UINavigationController *navigationController;
@property (nonatomic, retain) IBOutlet UIToolbar *toolbar;
@property (nonatomic, retain) IBOutlet UIBarButtonItem *lastUpdateLabel;

- (IBAction)selectHome:(id)sender;

@end

执行文件:

- (void)viewDidLoad {
        [super viewDidLoad];

    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 150.0f, 20.0f)];
    label.text = @"last updated...";
    label.textColor = [UIColor colorWithWhite:1.0 alpha:1.0];
    label.backgroundColor = [UIColor clearColor];
    label.textAlignment = UITextAlignmentCenter;
    label.font = [UIFont boldSystemFontOfSize:13.0];
    label.userInteractionEnabled = NO;

    lastUpdateLabel = [[UIBarButtonItem alloc] initWithCustomView:label];
    [label release];
    [toolbar setItems:[NSArray arrayWithObject:lastUpdateLabel]];


    [self.view addSubview:self.navigationController.view];
    //[self.view addSubview:toolbar];
    //[self.navigationController.view addSubview:toolbar];

    [self.navigationController.view setFrame:self.view.frame];

}

非常感谢任何帮助!

编辑:

我删除了 Nib 中所有会导致工具栏出现/被修改的内容，并将 viewDidLoad 中的代码更新为以下内容:

    self.navigationController.toolbarHidden = NO;

    //creating label in tool bar 
    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 150.0f, 20.0f)];
    label.text = @"last updated...";
    label.textColor = [UIColor colorWithWhite:1.0 alpha:1.0];
    label.backgroundColor = [UIColor clearColor];
    label.textAlignment = UITextAlignmentCenter;
    //label.highlightedTextColor = [UIColor colorWithWhite:0.5 alpha:1.0];
    //label.highlighted = YES;
    label.font = [UIFont systemFontOfSize:13.0];
    label.userInteractionEnabled = NO;

    UIBarButtonItem *lastUpdateLabel = [[UIBarButtonItem alloc] initWithCustomView:label];
    //[lastUpdateLabel initWithCustomView:label];
    //[label release];
    //[toolbar setItems:[NSArray arrayWithObject:lastUpdateLabel]];
    [self setToolbarItems:[NSArray arrayWithObject:lastUpdateLabel]];

我最终得到了一个空白的工具栏。我启动调试器，这就是我所看到的: 啊哈! lastUpdateLabel 的 View 的 _text 字段超出范围!但为什么？我该如何补救？

编辑 2:

我已经能够使用以下代码添加标签和 NSActivityIndi​​cator:

@synthesize refreshDataButton;
//...
self.navigationController.toolbarHidden = NO;

    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(20.0f, 0.0f, 80.0f, 40.0f)];
    label.text = @"last updated...";
    label.textColor = [UIColor colorWithWhite:1.0 alpha:1.0];
    label.backgroundColor = [UIColor clearColor];
    label.textAlignment = UITextAlignmentCenter;
    label.font = [UIFont systemFontOfSize:13.0];
    label.userInteractionEnabled = NO;
    [self.toolbar addSubview:label];

// create activity indicator
    //                        dist frm lft, dist frm top
    CGRect frame = CGRectMake(   90.0,         11.0,      25.0, 25.0);      
    UIActivityIndicatorView *loading = [[UIActivityIndicatorView alloc] initWithFrame:frame];   
    loading.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhite; 
    [loading sizeToFit];    
    loading.autoresizingMask = (UIViewAutoresizingFlexibleLeftMargin | 
                                UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleTopMargin | 
                                UIViewAutoresizingFlexibleBottomMargin);    
    [loading startAnimating];

    [self.toolbar addSubview:loading];

但是当我尝试添加一个 UIBarButtonItem 时我运气不好(没有显示在工具栏中):

self.refreshDataButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:100 target:self action:@selector(refreshDataButtonTapped)];
[self setToolbarItems:[NSArray arrayWithObject:refreshDataButton]];

这是头文件:

 #import <UIKit/UIKit.h>
//#import <CoreData/CoreData.h>

@interface ParkingRootViewController : UIViewController {
    UINavigationController *navigationController;
    UIToolbar *toolbar;
    UIBarButtonItem *refreshDataButton;
    //UIActivityIndicatorView *loading;
}

@property (nonatomic, retain) IBOutlet UINavigationController *navigationController;
@property (nonatomic, retain) IBOutlet UIToolbar *toolbar;
@property (nonatomic, retain) UIBarButtonItem *refreshDataButton;
//@property (nonatomic, retain) IBOutlet UIActivityIndicatorView *loading;


@property (nonatomic, readonly) NSString *applicationDocumentsDirectory;

-(IBAction)selectHome:(id)sender;
-(void)testCoreData;
-(void)refreshDataButtonTapped;

@end

最佳答案

代码应该可以工作...我可以提出一些建议。而不是:

[toolbar setItems:[NSArray arrayWithObject:lastUpdateLabel]];

试试这个:

[toolbar setItems:[NSArray arrayWithObject:lastUpdateLabel] animated:YES];

此外，由于您使用的是 UINavigationController，因此 NavController 带有自己的工具栏，您可以根据需要使用。默认情况下它是隐藏的，您可以通过执行以下操作使其可见:

self.navigationController.toolbarHidden = NO;

你可以通过这样做来设置它的工具栏项目:

[self setToolbarItems:[NSArray arrayWithObject:lastUpdateLabel]];

希望这个花絮能帮到你。祝你好运!

关于ios - 以编程方式将项目添加到 UIToolbar 不起作用，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/4476361/