如何在 iOS 中以编程方式设置纵横比约束?

问题描述

我为我的视图控制器使用了自动布局.我已经在约束中设置了 V 和 H 位置，但我想知道当按钮变为 5s、6 和 6 Plus 时如何增加按钮大小.这是我为登录按钮添加约束的方式:

I have used auto layout for my view controllers. I have set the V and H positions in constraints, but I want to know how can I increase my button size when it changes to 5s, 6 and 6 Plus. This is the way I added constraints for the login button:

NSArray *btncon_V=[NSLayoutConstraint constraintsWithVisualFormat:@"V:[btnLogin(40)]" options:0 metrics:nil views:viewsDictionary];
[btnLogin addConstraints:btncon_V];

NSArray *btncon_POS_H=[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-100-[btnLogin]-100-|" options:0 metrics:nil views:viewsDictionary];
[self.view addConstraints:btncon_POS_H];


NSArray *btncon_POS_V=[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-70-[Title]-130-[lblFirst]-0-[lblSecond]-20-[textusername]-10-[txtpassword]-10-[btnLogin]" options:0 metrics:nil views:viewsDictionary];

[self.view addConstraints:btncon_POS_V];

但我的问题是，虽然它管理左侧和右侧间隙，但由于高度是固定的，它在 iPhone 6 和 6 Plus 中被拉伸.如何根据屏幕尺寸增加尺寸?我认为这可能是纵横比，但是如何在代码中设置纵横比约束?

But my problem is that while it manages the left and right side gap, it's getting stretched in iPhone 6 and 6 Plus since the height is fixed. How can I increase the size according to the screen size? I think this might be the aspect ratio, but how can I set the aspect ratio constraint in code?

推荐答案

像这样.尝试一次.

[self.yourview setTranslatesAutoresizingMaskIntoConstraints:NO];
[self.yourview addConstraint:[NSLayoutConstraint
                                  constraintWithItem:self.yourview
                                  attribute:NSLayoutAttributeHeight
                                  relatedBy:NSLayoutRelationEqual
                                  toItem:self.yourview
                                  attribute:NSLayoutAttributeWidth
                                  multiplier:(self.yourview.frame.size.height / self.yourview.frame.size.width)
                                  constant:0]];

或代替 (self.yourview.frame.size.height/self.yourview.frame.size.width) 您可以使用任何浮点值.谢谢.

or in the place of (self.yourview.frame.size.height / self.yourview.frame.size.width) you can use any float value. Thanks.

Swift 3.0 -

self.yourview!.translatesAutoresizingMaskIntoConstraints = false
self.yourview!.addConstraint(NSLayoutConstraint(item: self.yourview!,
                                          attribute: NSLayoutAttribute.height,
                                          relatedBy: NSLayoutRelation.equal,
                                          toItem: self.yourview!,
                                          attribute: NSLayoutAttribute.width,
                                          multiplier: self.yourview.frame.size.height / self.yourview.frame.size.width,
                                          constant: 0))

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