如何阻止时间UILabel在每个时间增量上调整大小? [英] How to stop a time UILabel from resizing at every time increment?

问题描述

我的应用程序中具有秒表功能，该功能使用居中的属性UILabel和比例间隔的字体来呈现时间.每次增加标签宽度时，都会产生弹跳效果，在快速移动时效果特别差.这是一个示例.

I have a stopwatch feature in my app that uses a centered attributed UILabel with a proportionally spaced font to render time. At every time increment the width of the label changes, creating a bouncing effect that looks especially bad at fast speeds. Here is an example.

我该如何解决?

iOS 9 UPDATE

现在它是单线的:

UIFont.monospacedDigitSystemFontOfSize(17, weight: UIFontWeightRegular)

此外，我上次尝试使用以下解决方案不适用于iOS9.在将其绊到标题中之前，浪费了很多时间进行调试.

Also, last time I tried, the solution below did not work for iOS 9. Wasted quite a bit of time debugging before stumbling on this in the header.

解决方案

事实证明，在iOS 7中使用文本工具包显得微不足道.

Turned out to be trivial with Text Kit in iOS 7.

确保已导入核心文本:

#import <CoreText/CoreText.h>

创建一个将比例数字转换为等距的设置:

Create a setting that converts proportional numbers into monospaced:

NSArray *monospacedSetting = @[@{UIFontFeatureTypeIdentifierKey: @(kNumberSpacingType),
                                 UIFontFeatureSelectorIdentifierKey: @(kMonospacedNumbersSelector)}];

通过添加UILabel使用的当前字体描述符来创建新的字体描述符:

Create a new font descriptor by appending the current one used by UILabel:

UIFontDescriptor *newDescriptor = [[timeLabel.font fontDescriptor] fontDescriptorByAddingAttributes:@{UIFontDescriptorFeatureSettingsAttribute: monospacedSetting}];

更新标签的字体:

// Size 0 to use previously set font size
timeLabel.font = [UIFont fontWithDescriptor:newDescriptor size:0];

推荐答案

在创建强制使用等宽数字的字体时，请使用等宽字体或传递参数:

Use a monospaced font or pass parameters when creating the font which force monospaced numbers:

//kNumberSpacingType 6
//kMonospacedNumbersSelector 0
NSArray *setting = @[
                         @{
                             UIFontFeatureTypeIdentifierKey: @(6),
                             UIFontFeatureSelectorIdentifierKey: @(0)
                             }
                         ];

return [UIFont fontWithDescriptor:[[self fontDescriptor] fontDescriptorByAddingAttributes:@{UIFontDescriptorFeatureSettingsAttribute : setting}] size:0.0];

这篇关于如何阻止时间UILabel在每个时间增量上调整大小?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！