UINavigationBar多行标题

Question

是否有一种直接的方法来覆盖导航控制器中导航栏中当前导航栏项目的titleView？我已经尝试创建一个新的UIView并用我自己的UIVIew替换topView的titleView属性但没有成功.

基本上,我想要导航栏标题的多行标题.有什么建议？

Answer 1

设置titleView属性UINavigationItem.例如,在视图控制器的viewDidLoad方法中,您可以执行以下操作:

UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 480, 44)];
label.backgroundColor = [UIColor clearColor];
label.numberOfLines = 2;
label.font = [UIFont boldSystemFontOfSize: 14.0f];
label.shadowColor = [UIColor colorWithWhite:0.0 alpha:0.5];
label.textAlignment = UITextAlignmentCenter;
label.textColor = [UIColor whiteColor];
label.text = @"This is a\nmultiline string";

self.navigationItem.titleView = label;

#if !__has_feature(objc_arc)
[label release];
#endif

它显示如下:

请记住,如果不是,titleView则忽略该属性.leftBarButtonItemnil

Answer 2

对于Swift:

let label = UILabel(frame: CGRectMake(0, 0, UIScreen.main.bounds.width, 44))
label.backgroundColor = UIColor.clearColor()
label.numberOfLines = 0
label.textAlignment = NSTextAlignment.Center
label.text = "multiline string"
self.navigationItem.titleView = label

对于swift 4:

    let label = UILabel(frame: CGRect(x: 0.0, y: 0.0, width: UIScreen.main.bounds.width, height: 44.0))
    label.backgroundColor = UIColor.clear
    label.numberOfLines = 0
    label.textAlignment = NSTextAlignment.center
    label.text = "first line\nsecond line"
    self.navigationItem.titleView = label   

Answer 3

Swift解决方案:

2行NavigationBar:

private func setupTitleView() {
    let topText = NSLocalizedString("key", comment: "")
    let bottomText = NSLocalizedString("key", comment: "")

    let titleParameters = [NSForegroundColorAttributeName : UIColor.<Color>(),
                           NSFontAttributeName : UIFont.<Font>]
    let subtitleParameters = [NSForegroundColorAttributeName : UIColor.<Color>(),
                              NSFontAttributeName : UIFont.<Font>]

    let title:NSMutableAttributedString = NSMutableAttributedString(string: topText, attributes: titleParameters)
    let subtitle:NSAttributedString = NSAttributedString(string: bottomText, attributes: subtitleParameters)

    title.appendAttributedString(NSAttributedString(string: "\n"))
    title.appendAttributedString(subtitle)

    let size = title.size()

    let width = size.width
    guard let height = navigationController?.navigationBar.frame.size.height else {return}

    let titleLabel = UILabel(frame: CGRectMake(0,0, width, height))
    titleLabel.attributedText = title
    titleLabel.numberOfLines = 0
    titleLabel.textAlignment = .Center

    navigationItem.titleView = titleLabel
}

2行 BarButton

    let string = NSLocalizedString("key", comment: "")
    let attributes = [NSForegroundColorAttributeName : UIColor.<Color>,
                      NSFontAttributeName : UIFont.<Font>]
    let size = (string as NSString).sizeWithAttributes(attributes)
    guard let height = navigationController?.navigationBar.frame.size.height else {return}
    let button:UIButton = UIButton(frame: CGRectMake(0, 0, size.width, height))
    button.setAttributedTitle(NSAttributedString(string: string, attributes: attributes), forState: .Normal)
    button.addTarget(self, action: #selector(<SELECTOR>), forControlEvents: .TouchUpInside)
    button.titleLabel?.numberOfLines = 0
    button.titleLabel?.textAlignment = .Right
    let rightBarButton = UIBarButtonItem(customView: button)
    navigationItem.rightBarButtonItem = rightBarButton

结果 -

Answer 4

经过大量的调整后,我仍然无法在iOS 8中获得petert的解决方案.这是适用于iOS 8/9的复制粘贴解决方案.幸得马特·柯蒂斯的github上后

- (void) viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];

    if(!self.navigationItem.titleView){
        self.navigationItem.titleView = ({
            UILabel *titleView = [UILabel new];
            titleView.numberOfLines = 0;
            titleView.textAlignment = NSTextAlignmentCenter;
            titleView.attributedText = [[NSAttributedString alloc] initWithString:@"2\nLINES" attributes:
                self.navigationController.navigationBar.titleTextAttributes
            ];

            [titleView sizeToFit];
            // You'll need to set your frame otherwise if your line breaks aren't explcit.

            titleView;
        });
    }
}

Answer 5

标签未居中时该怎么办

如果您遇到与我相同的问题 - 由于后退按钮，该标签未在导航项中居中，请将您的 UILabel 嵌入到 UIView。UILabel 然后不会被迫随着它的文本增长，而是在它的宽度增加视图的宽度时停止增长。您可以在此处找到有关此问题的更多信息：无法在导航栏的中心设置 titleView 因为后退按钮（达伦的回答）

不居中：

- (void)setTwoLineTitle:(NSString *)titleText color:(UIColor *)color font:(UIFont *)font {
    CGFloat titleLabelWidth = [UIScreen mainScreen].bounds.size.width/2;

    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, titleLabelWidth, 44)];
    label.backgroundColor = [UIColor clearColor];
    label.numberOfLines = 2;
    label.font = font;
    label.adjustsFontSizeToFitWidth = YES;
    label.textAlignment = UITextAlignmentCenter;
    label.textColor = color;
    label.text = titleText;

    self.navigationItem.titleView = label;
}

居中：

- (void)setTwoLineTitle:(NSString *)titleText color:(UIColor *)color font:(UIFont *)font {
    CGFloat titleLabelWidth = [UIScreen mainScreen].bounds.size.width/2;

    UIView *wrapperView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, titleLabelWidth, 44)];

    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, titleLabelWidth, 44)];
    label.backgroundColor = [UIColor clearColor];
    label.numberOfLines = 2;
    label.font = font;
    label.adjustsFontSizeToFitWidth = YES;
    label.textAlignment = UITextAlignmentCenter;
    label.textColor = color;
    label.text = titleText;

    [wrapperView addSubview:label];

    self.navigationItem.titleView = wrapperView;
}