Question

我有一个UINavigationBar并设置了leftBarButtonItem和rightBarButtonItem。左栏设置为：

UIButton *backButton = [UIButton buttonWithType:UIButtonTypeCustom];
        [backButton setImage:[UIImage imageNamed:@"back.png"] forState:UIControlStateNormal];
        UIBarButtonItem *myButton = [[[UIBarButtonItem alloc] initWithCustomView:backButton] autorelease];
        self.navigationItem.leftBarButtonItem = myButton;

，右栏按钮设置为：

UIButton *doneBtn = [UIButton buttonWithType:UIButtonTypeCustom];
 UIImage *doneButtonImage = nil;
        doneButtonImage = [UIImage imageNamed:@"done.png"];
        [doneBtn setImage:doneButtonImage forState:UIControlStateNormal];
  doneBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:doneBtn];
    self.navigationItem.rightBarButtonItem = doneBarButtonItem;

背面的宽度是23px，完成的是72px，所以它们不相等。现在的问题是我有一个标签，我想要一直在中心..如果标签中的文字太长，以至于它干扰了正确的条形按钮，我想剪辑文本。这是我如何设置它：

titleLabel = [[UILabel alloc] initWithFrame:CGRectZero];
    titleLabel.text = self.pageTitle; // Can't change
    titleLabel.adjustsFontSizeToFitWidth = YES;
    titleLabel.clipsToBounds = YES;
    titleLabel.numberOfLines = 1;
    titleLabel.font = [UIFont fontWithName:@"PTSans-Narrow" size:30.0]; 
    titleLabel.textColor = [UIColor colorWithWhite:0.6 alpha:1.0];
    titleLabel.backgroundColor = [UIColor yellowColor];
    titleLabel.autoresizingMask = UIViewAutoresizingFlexibleHeight;
    titleLabel.textAlignment = UITextAlignmentCenter;
    [titleLabel sizeToFit];
    titleLabel.frameHeight = self.navigationController.navigationBar.frameHeight;


 self.navigationItem.titleView = titleLabel;

然而，这并不是标题的中心..我怎么能这样做？

Answer 1

我建议先计算self.pageTitle的宽度然后相应地设置titleLabel的位置。我更喜欢这个： -

titleLabel = [[UILabel alloc] init];
titleLabel.text = self.pageTitle; // Can't change

**CGSize maximumTitleLabelSize = CGSizeMake(200,40);//Set maximum width that an self.pageTitle can have.
CGSize expectedLabelSize = [titleLabel.text titleLabel.font 
                                            constrainedToSize:maximumTitleLabelSize
                                                lineBreakMode:UILineBreakModeWordWrap];
//adjust the label the the new width.
CGRect newFrame = titleLabel.frame;
newFrame.size.width = expectedLabelSize.width;
titleLabel.size.width = newFrame.size.width;**    
if(titleLabel.size.width==100)
{
titleLabel.frame = cgRectMake(85,5,titleLabel.size.width,30);
}
else if(titleLabel.size.width==200)
{
titleLabel.frame = cgRectMake(36,5,titleLabel.size.width,30);
}

titleLabel.adjustsFontSizeToFitWidth = YES;
titleLabel.clipsToBounds = YES;
titleLabel.numberOfLines = 1;
titleLabel.font = [UIFont fontWithName:@"PTSans-Narrow" size:30.0]; 
titleLabel.textColor = [UIColor colorWithWhite:0.6 alpha:1.0];
titleLabel.backgroundColor = [UIColor yellowColor];
titleLabel.autoresizingMask = UIViewAutoresizingFlexibleHeight;
titleLabel.textAlignment = UITextAlignmentCenter;
[titleLabel sizeToFit];
titleLabel.frameHeight = self.navigationController.navigationBar.frameHeight;

self.navigationItem.titleView = titleLabel;

试试这个。它会帮助你。谢谢：）

Answer 2

这是最简单的解决方案，在将sizeToFit添加到titleView之前使用UILabel *titleLabel = [[UILabel alloc] init]; titleLabel.text = @"My Title"; titleLabel.font = [UIFont boldSystemFontOfSize:17.0f]; titleLabel.textColor = [UIColor whiteColor]; [titleLabel sizeToFit]; self.navigationItem.titleView = titleLabel;方法：

{{1}}

Answer 3

不要使用NavigationItem添加左右栏按钮，而是使用addsubview方法为导航栏添加自定义按钮。

Answer 4

使用工具栏将多个按钮添加到导航栏。

   // create a toolbar to have two buttons in the right
UIToolbar* tools = [[UIToolbar alloc] initWithFrame:CGRectMake(0, 0, 133, 44.01)];

// create the array to hold the buttons, which then gets added to the toolbar
NSMutableArray* buttons = [[NSMutableArray alloc] initWithCapacity:3];

// create a standard "add" button
UIBarButtonItem* bi = [[UIBarButtonItem alloc]`enter code here`
initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:NULL];
bi.style = UIBarButtonItemStyleBordered;
[buttons addObject:bi];
[bi release];

// create a spacer
bi = [[UIBarButtonItem alloc]
initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];
[buttons addObject:bi];
[bi release];

// create a standard "refresh" button
bi = [[UIBarButtonItem alloc]
initWithBarButtonSystemItem:UIBarButtonSystemItemRefresh target:self action:@selector(refresh:)];
bi.style = UIBarButtonItemStyleBordered;
[buttons addObject:bi];
[bi release];

// stick the buttons in the toolbar
[tools setItems:buttons animated:NO];

[buttons release];

// and put the toolbar in the nav bar
self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:tools];
[tools release];

Answer 5

你只需使用此代码就可以正常运行

UILabel *titleLabel = [[UILabel alloc]initWithFrame:CGRectMake(0, 5, 190, 30)];
titleLabel.textColor = [UIColor whiteColor];
titleLabel.textAlignment = UITextAlignmentCenter;
titleLabel.text =@"My Wish List"; 
titleLabel.backgroundColor = [UIColor clearColor];
titleLabel.font = [UIFont fontWithName:@"Copperplate" size:16.0];
titleLabel.minimumFontSize = 10;
titleLabel.autoresizingMask=UIViewAutoresizingFlexibleWidth;
self.navigationItem.titleView = titleLabel;
[titleLabel release];

我在我的项目中也使用此代码....... ： - ）

将UILabel置于UINavigationBar中心

5 个答案: