问题
I have a UILabel which shows the output of a timer in the format MM:ss:SS (minutes, seconds, centiseconds), however it "shakes" from left to right as the width of the centiseconds changes - "11" is narrower than "33" for example.
Is there any way I can mitigate this? I've tried centring it, giving it a fixed width but they haven't seemed to help.
回答1:
Since iOS 9.0, the system font uses proportional digits. If you want monospaced digits, there's a variant font which you can obtain using +[UIFont monospacedDigitSystemFontOfSize:weight:]. This only works for the system font.
If you want to work with another font, you try to ask for a monospaced variant, but there may not be one. Given a UIFont, you can request its fontDescriptor, then ask that for a similar font descriptor that's monospaced (not just for digits) using -[UIFontDescriptor fontDescriptorWithSymbolicTraits:] and UIFontDescriptorTraitMonoSpace. You can then create a new font by passing the new font descriptor to +[UIFont fontWithDescriptor:size:].
However, I doubt there's a monospace variant of Impact. It's not suitable for your purpose.
回答2:
I had the same problem. @KenThomases answer works. Here's the Swift version:
// replace whatever font your using with this font instead to stop the shaking
UIFont.monospacedDigitSystemFont(ofSize: 19, weight: UIFont.Weight.regular)
ie:
yourLabel.font = UIFont.monospacedDigitSystemFont(ofSize: 19, weight: UIFont.Weight.regular)
FYI there are other UIFont.Weight weights:
.black, .bold, .heavy, .light, .medium, .regular, .semibold, .thin, .ultraLight
According to this other answer the fonts below are system generated fonts that are also monospaced so they won't shake either:
Courier
Courier-Bold
Courier-BoldOblique
Courier-Oblique
CourierNewPS-BoldItalicMT
CourierNewPS-BoldMT
CourierNewPS-ItalicMT
CourierNewPSMT
Menlo-Bold
Menlo-BoldItalic
Menlo-Italic
Menlo-Regular
ie:
// no shaking
yourLabel.font = UIFont(name: "Menlo-Regular", size: 19)
If your using just numeric digits then HelveticaNeue is also monospaced and it doesn't shake but it's questionable. Read the comments below this answer before using this font.
ie:
// no shaking but apparently you can only use numbers not letters
yourLabel.font = UIFont(name: "HelveticaNeue", size: 19)
回答3:
Use A monospaced font, also called a fixed-pitch, fixed-width, or non-proportional font, is a font whose letters and characters each occupy the same amount of horizontal space. Examples of monospaced fonts include Courier, Courier New, Lucida Console, Monaco, and Consolas
来源：https://stackoverflow.com/questions/33800488/ios-prevent-timer-uilabel-shaking-when-numbers-change