如何设置 UIBarButtonItem 的字体大小？

Question

我找不到在自定义 UIBarButtonItem 中设置标题字体大小的方法。我能想到解决这个问题的唯一方法是将其设置为图像，我想避免这种情况。还有其他建议吗？

Answer 1

Objective-C：

NSUInteger fontSize = 20;
UIFont *font = [UIFont boldSystemFontOfSize:fontSize];
NSDictionary *attributes = @{NSFontAttributeName: font};

UIBarButtonItem *item = [[UIBarButtonItem alloc] init];

[item setTitle:@"Some Text"];
[item setTitleTextAttributes:attributes forState:UIControlStateNormal];

self.navigationItem.rightBarButtonItem = item;

斯威夫特：

let fontSize:CGFloat = 20;
let font:UIFont = UIFont.boldSystemFont(ofSize: fontSize);
let attributes:[String : Any] = [NSFontAttributeName: font];
    
let item = UIBarButtonItem.init();
    
item.title = "Some Text";
item.setTitleTextAttributes(attributes, for: UIControlState.normal);
    
self.navigationItem.rightBarButtonItem = item;

Answer 2

作为 kennytm 建议 的具体示例，您可以使用如下内容创建 UIBarButtonItem：

UILabel *txtLabel = [[UILabel alloc] initWithFrame:rect];
txtLabel.backgroundColor = [UIColor clearColor];
txtLabel.textColor = [UIColor lightGrayColor];
txtLabel.text = @"This is a custom label";
UIBarButtonItem *btnText = [[[UIBarButtonItem alloc] initWithCustomView:txtLabel] autorelease];

然后，您可以将其添加为 UIToolbar 上的居中文本，例如：（

UIToolbar *toolBar = [[UIToolbar alloc] initWithFrame:rect];
toolBar.barStyle = UIBarStyleBlackTranslucent;
UIBarButtonItem *flexSpace1 = [[[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil] autorelease];
UIBarButtonItem *flexSpace2 = [[[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil] autorelease];

[toolBar setItems:[NSArray arrayWithItems:flexSpace1, btnText, flexSpace2, nil]];

当然，为了获得正确的格式，用于初始化 txtLabel 的 rect 和 toolBar 应该是正确的大小......但这是另一个练习。）

Answer 3

创建 UILabel 并使用 -initWithCustomView:。

Answer 4

Swift5：

let item = UIBarButtonItem(title: "", style: .plain, target: self, action: #selector(self.onItemTapped))
let font:UIFont = UIFont(name: "", size: 18) ?? UIFont()
item.setTitleTextAttributes([NSAttributedString.Key.font: font], for: UIControl.State.normal)

Answer 5

[[UIBarButtonItem appearance]setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
                                                     [UIColor colorWithRed:245.0/255.0 green:245.0/255.0 blue:245.0/255.0 alpha:1.0], NSForegroundColorAttributeName,
                                                     [UIFont fontWithName:@"FONT-NAME" size:21.0], NSFontAttributeName, nil]
                                           forState:UIControlStateNormal];

Answer 6

let barButtonItem: UIBarButtonItem = UIBarButtonItem(title: "Title",
                                                     style: .plain,
                                                     target: nil,
                                                     action: nil)
let font: UIFont = UIFont.systemFont(ofSize: 12.0)
let textAttributes: [NSAttributedString.Key: Any] = [.font: font]

barButtonItem.setTitleTextAttributes(textAttributes, for: .normal)
barButtonItem.setTitleTextAttributes(textAttributes, for: .selected)