我可以使用哪些常数在自动布局默认水族空间？ [英] What constant can I use for the default Aqua space in Autolayout?

问题描述

根据<一href=\"https://developer.apple.com/library/mac/#documentation/UserExperience/Conceptual/AutolayoutPG/Articles/constraintFundamentals.html#//apple_ref/doc/uid/TP40010853-CH2-SW1\">Cocoa自动布局指南，我可以使用破折号，在视觉约束格式语言表示标准的水族空间：

According to the Cocoa Auto Layout Guide, I can use a dash in the visual constraint format language to "denote the standard Aqua space:"

[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"[a]-[b]"
                                                             options:0
                                                             metrics:nil
                                                               views:viewDict]];

不过，我似乎无法找到一个 NSLayout ... 常量或方法，可以让我做同样的事情，如果我建立一个约束条件的没有的使用可视化格式语言：

However, I can't seem to find an NSLayout... constant or method that allows me to do the same thing if I'm building a constraint without using the visual format language:

[self addConstraint:[NSLayoutConstraint constraintWithItem:a
                                                 attribute:NSLayoutAttributeTrailing
                                                 relatedBy:NSLayoutRelationEqual
                                                    toItem:b
                                                 attribute:NSLayoutAttributeLeading
                                                multiplier:1.0f
                                                  constant:<# ??? #>]];

有没有一个恒定的（或其它值或方法），我可以用在这种情况下定义水族空间？

Is there a constant (or another value or method) that I can use to define the Aqua space in such a situation?

推荐答案

我已经找到了标准水族空间是兄弟之间的意见8.0和20.0的景色，它的父之间。

I've found the "standard Aqua space" to be 8.0 between sibling views, and 20.0 between a view and its superview.

NSView* view = [NSView new] ;
NSLayoutConstraint* constraintWithStandardConstantBetweenSiblings = [NSLayoutConstraint constraintsWithVisualFormat:@"[view]-[view]"  options:0  metrics:nil  views:NSDictionaryOfVariableBindings(view) ] [0] ;
CGFloat standardConstantBetweenSiblings = constraintWithStandardConstantBetweenSiblings.constant ;    // 8.0

NSView* superview = [NSView new] ;
[superview addSubview:view] ;
NSLayoutConstraint* constraintWithStandardConstantBetweenSuperview = [NSLayoutConstraint constraintsWithVisualFormat:@"[view]-|"  options:0  metrics:nil  views:NSDictionaryOfVariableBindings(view) ] [0] ;
CGFloat standardConstantBetweenSuperview = constraintWithStandardConstantBetweenSuperview.constant ;    // 20.0

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