自动布局让我的生活很困难。从理论上讲，当我转换的时候，它会非常有用，但我似乎一直在与它作斗争。
我做了一个演示项目来寻求帮助。有人知道如何使视图之间的空间增加或减少均匀，每当视图调整大小?
下面是三个标签(手动垂直对齐):
我想要的是，当我旋转时，它们均匀地调整间距(而不是视图大小)。默认情况下，顶部和底部视图向中心挤压:
当前回答
基于Ben Dolman的回答，这将更均匀地分配视图(使用填充等):
+(NSArray *)constraintsForEvenDistributionOfItems:(NSArray *)views
relativeToCenterOfItem:(id)toView vertically:(BOOL)vertically
{
NSMutableArray *constraints = [NSMutableArray new];
NSLayoutAttribute attr = vertically ? NSLayoutAttributeCenterY : NSLayoutAttributeCenterX;
CGFloat min = 0.25;
CGFloat max = 1.75;
CGFloat d = (max-min) / ([views count] - 1);
for (NSUInteger i = 0; i < [views count]; i++) {
id view = views[i];
CGFloat multiplier = i * d + min;
NSLayoutConstraint *constraint = [NSLayoutConstraint constraintWithItem:view
attribute:attr
relatedBy:NSLayoutRelationEqual
toItem:toView
attribute:attr
multiplier:multiplier
constant:0];
[constraints addObject:constraint];
}
return constraints;
}
其他回答
大多数解决方案都依赖于项目的奇数，这样你就可以把中间的项目放在中间。如果你有偶数个项目想要平均分配呢?这是一个更一般的解。这个类别将沿垂直或水平轴均匀分布任意数量的项目。
在它们的父视图中垂直分布4个标签的示例:
[self.view addConstraints:
[NSLayoutConstraint constraintsForEvenDistributionOfItems:@[label1, label2, label3, label4]
relativeToCenterOfItem:self.view
vertically:YES]];
NSLayoutConstraint + EvenDistribution.h
@interface NSLayoutConstraint (EvenDistribution)
/**
* Returns constraints that will cause a set of views to be evenly distributed horizontally
* or vertically relative to the center of another item. This is used to maintain an even
* distribution of subviews even when the superview is resized.
*/
+ (NSArray *) constraintsForEvenDistributionOfItems:(NSArray *)views
relativeToCenterOfItem:(id)toView
vertically:(BOOL)vertically;
@end
NSLayoutConstraint + EvenDistribution.m
@implementation NSLayoutConstraint (EvenDistribution)
+(NSArray *)constraintsForEvenDistributionOfItems:(NSArray *)views
relativeToCenterOfItem:(id)toView vertically:(BOOL)vertically
{
NSMutableArray *constraints = [NSMutableArray new];
NSLayoutAttribute attr = vertically ? NSLayoutAttributeCenterY : NSLayoutAttributeCenterX;
for (NSUInteger i = 0; i < [views count]; i++) {
id view = views[i];
CGFloat multiplier = (2*i + 2) / (CGFloat)([views count] + 1);
NSLayoutConstraint *constraint = [NSLayoutConstraint constraintWithItem:view
attribute:attr
relatedBy:NSLayoutRelationEqual
toItem:toView
attribute:attr
multiplier:multiplier
constant:0];
[constraints addObject:constraint];
}
return constraints;
}
@end
我做了一个函数可能会有帮助。 用法示例:
[self.view addConstraints: [NSLayoutConstraint fluidConstraintWithItems:NSDictionaryOfVariableBindings(button1, button2, button3)
asString:@[@"button1", @"button2", @"button3"]
alignAxis:@"V"
verticalMargin:100
horizontalMargin:50
innerMargin:25]];
会导致垂直分布(不好意思没有10个声望来嵌入图像)。如果你改变坐标轴和一些边距值
alignAxis:@"H"
verticalMargin:120
horizontalMargin:20
innerMargin:10
你会得到水平分布。
我是iOS的新手，但是voilà !
EvenDistribution.h
@interface NSLayoutConstraint (EvenDistribution)
/**
* Returns constraints that will cause a set of subviews
* to be evenly distributed along an axis.
*/
+ (NSArray *) fluidConstraintWithItems:(NSDictionary *) views
asString:(NSArray *) stringViews
alignAxis:(NSString *) axis
verticalMargin:(NSUInteger) vMargin
horizontalMargin:(NSUInteger) hMargin
innerMargin:(NSUInteger) inner;
@end
EvenDistribution.m
#import "EvenDistribution.h"
@implementation NSLayoutConstraint (EvenDistribution)
+ (NSArray *) fluidConstraintWithItems:(NSDictionary *) dictViews
asString:(NSArray *) stringViews
alignAxis:(NSString *) axis
verticalMargin:(NSUInteger) vMargin
horizontalMargin:(NSUInteger) hMargin
innerMargin:(NSUInteger) iMargin
{
NSMutableArray *constraints = [NSMutableArray arrayWithCapacity: dictViews.count];
NSMutableString *globalFormat = [NSMutableString stringWithFormat:@"%@:|-%d-",
axis,
[axis isEqualToString:@"V"] ? vMargin : hMargin
];
for (NSUInteger i = 0; i < dictViews.count; i++) {
if (i == 0)
[globalFormat appendString:[NSString stringWithFormat: @"[%@]-%d-", stringViews[i], iMargin]];
else if(i == dictViews.count - 1)
[globalFormat appendString:[NSString stringWithFormat: @"[%@(==%@)]-", stringViews[i], stringViews[i-1]]];
else
[globalFormat appendString:[NSString stringWithFormat: @"[%@(==%@)]-%d-", stringViews[i], stringViews[i-1], iMargin]];
NSString *localFormat = [NSString stringWithFormat: @"%@:|-%d-[%@]-%d-|",
[axis isEqualToString:@"V"] ? @"H" : @"V",
[axis isEqualToString:@"V"] ? hMargin : vMargin,
stringViews[i],
[axis isEqualToString:@"V"] ? hMargin : vMargin];
[constraints addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:localFormat
options:0
metrics:nil
views:dictViews]];
}
[globalFormat appendString:[NSString stringWithFormat:@"%d-|",
[axis isEqualToString:@"V"] ? vMargin : hMargin
]];
[constraints addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:globalFormat
options:0
metrics:nil
views:dictViews]];
return constraints;
}
@end
这里还有另一个答案。我在回答一个类似的问题时看到了这个问题的链接。我没有看到任何与我类似的答案。所以我想写在这里。
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = UIColor.whiteColor()
setupViews()
}
var constraints: [NSLayoutConstraint] = []
func setupViews() {
let container1 = createButtonContainer(withButtonTitle: "Button 1")
let container2 = createButtonContainer(withButtonTitle: "Button 2")
let container3 = createButtonContainer(withButtonTitle: "Button 3")
let container4 = createButtonContainer(withButtonTitle: "Button 4")
view.addSubview(container1)
view.addSubview(container2)
view.addSubview(container3)
view.addSubview(container4)
[
// left right alignment
container1.leftAnchor.constraintEqualToAnchor(view.leftAnchor, constant: 20),
container1.rightAnchor.constraintEqualToAnchor(view.rightAnchor, constant: -20),
container2.leftAnchor.constraintEqualToAnchor(container1.leftAnchor),
container2.rightAnchor.constraintEqualToAnchor(container1.rightAnchor),
container3.leftAnchor.constraintEqualToAnchor(container1.leftAnchor),
container3.rightAnchor.constraintEqualToAnchor(container1.rightAnchor),
container4.leftAnchor.constraintEqualToAnchor(container1.leftAnchor),
container4.rightAnchor.constraintEqualToAnchor(container1.rightAnchor),
// place containers one after another vertically
container1.topAnchor.constraintEqualToAnchor(view.topAnchor),
container2.topAnchor.constraintEqualToAnchor(container1.bottomAnchor),
container3.topAnchor.constraintEqualToAnchor(container2.bottomAnchor),
container4.topAnchor.constraintEqualToAnchor(container3.bottomAnchor),
container4.bottomAnchor.constraintEqualToAnchor(view.bottomAnchor),
// container height constraints
container2.heightAnchor.constraintEqualToAnchor(container1.heightAnchor),
container3.heightAnchor.constraintEqualToAnchor(container1.heightAnchor),
container4.heightAnchor.constraintEqualToAnchor(container1.heightAnchor)
]
.forEach { $0.active = true }
}
func createButtonContainer(withButtonTitle title: String) -> UIView {
let view = UIView(frame: .zero)
view.translatesAutoresizingMaskIntoConstraints = false
let button = UIButton(type: .System)
button.translatesAutoresizingMaskIntoConstraints = false
button.setTitle(title, forState: .Normal)
view.addSubview(button)
[button.centerYAnchor.constraintEqualToAnchor(view.centerYAnchor),
button.leftAnchor.constraintEqualToAnchor(view.leftAnchor),
button.rightAnchor.constraintEqualToAnchor(view.rightAnchor)].forEach { $0.active = true }
return view
}
}
同样，这也可以用iOS9 UIStackViews很容易做到。
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = UIColor.greenColor()
setupViews()
}
var constraints: [NSLayoutConstraint] = []
func setupViews() {
let container1 = createButtonContainer(withButtonTitle: "Button 1")
let container2 = createButtonContainer(withButtonTitle: "Button 2")
let container3 = createButtonContainer(withButtonTitle: "Button 3")
let container4 = createButtonContainer(withButtonTitle: "Button 4")
let stackView = UIStackView(arrangedSubviews: [container1, container2, container3, container4])
stackView.translatesAutoresizingMaskIntoConstraints = false
stackView.axis = .Vertical
stackView.distribution = .FillEqually
view.addSubview(stackView)
[stackView.topAnchor.constraintEqualToAnchor(view.topAnchor),
stackView.bottomAnchor.constraintEqualToAnchor(view.bottomAnchor),
stackView.leftAnchor.constraintEqualToAnchor(view.leftAnchor, constant: 20),
stackView.rightAnchor.constraintEqualToAnchor(view.rightAnchor, constant: -20)].forEach { $0.active = true }
}
func createButtonContainer(withButtonTitle title: String) -> UIView {
let button = UIButton(type: .Custom)
button.translatesAutoresizingMaskIntoConstraints = false
button.backgroundColor = UIColor.redColor()
button.setTitleColor(UIColor.whiteColor(), forState: .Normal)
button.setTitle(title, forState: .Normal)
let buttonContainer = UIStackView(arrangedSubviews: [button])
buttonContainer.distribution = .EqualCentering
buttonContainer.alignment = .Center
buttonContainer.translatesAutoresizingMaskIntoConstraints = false
return buttonContainer
}
}
注意，这与上面的方法完全相同。它添加了四个容器视图，这些视图都是均等填充的，每个堆栈视图都添加了一个视图，并在中间对齐。但是，这个版本的UIStackView减少了一些代码，看起来不错。
是的，你可以只在接口构建器中这样做，而不需要编写代码——需要注意的是，你是在调整标签的大小，而不是分配空白。在本例中，将标签2的X和Y对齐到父视图，使其固定在中心。然后将标签1的垂直空间设置为superview，标签2设置为standard，重复标签3。在设置标签2之后，设置标签1和3最简单的方法是调整它们的大小，直到它们断开。
这是水平显示，注意标签1和2之间的垂直空间被设置为标准:
这是竖屏版本:
我意识到，由于标签之间的标准空间和父视图的标准空间之间的差异，它们在基线之间不是绝对100%等间距的。如果这让您感到困扰，可以将大小设置为0而不是standard
Here is a solution that will vertically center any number of subviews, even if they have unique sizes. What you want to do is make a mid-level container, center that in the superview, then put all the subviews in the container and arrange them with respect to one another. But crucially you also need to constrain them to the top and bottom of the container, so the container can be correctly sized and centered in the superview. By figuring the correct height from its subviews, the container can be vertically centered.
在本例中，self是位于所有子视图居中的父视图。
NSArray *subviews = @[ (your subviews in top-to-bottom order) ];
UIView *container = [[UIView alloc] initWithFrame:CGRectZero];
container.translatesAutoresizingMaskIntoConstraints = NO;
for (UIView *subview in subviews) {
subview.translatesAutoresizingMaskIntoConstraints = NO;
[container addSubview:subview];
}
[self addSubview:container];
[self addConstraint:[NSLayoutConstraint constraintWithItem:container attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual
toItem:self attribute:NSLayoutAttributeLeft multiplier:1.0f constant:0.0f]];
[self addConstraint:[NSLayoutConstraint constraintWithItem:container attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual
toItem:self attribute:NSLayoutAttributeRight multiplier:1.0f constant:0.0f]];
[self addConstraint:[NSLayoutConstraint constraintWithItem:container attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual
toItem:self attribute:NSLayoutAttributeCenterY multiplier:1.0f constant:0.0f]];
if (0 < subviews.count) {
UIView *firstSubview = subviews[0];
[container addConstraint:[NSLayoutConstraint constraintWithItem:firstSubview attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual
toItem:container attribute:NSLayoutAttributeTop multiplier:1.0f constant:0.0f]];
UIView *lastSubview = subviews.lastObject;
[container addConstraint:[NSLayoutConstraint constraintWithItem:lastSubview attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual
toItem:container attribute:NSLayoutAttributeBottom multiplier:1.0f constant:0.0f]];
UIView *subviewAbove = nil;
for (UIView *subview in subviews) {
[container addConstraint:[NSLayoutConstraint constraintWithItem:subview attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual
toItem:container attribute:NSLayoutAttributeCenterX multiplier:1.0f constant:0.0f]];
if (subviewAbove) {
[container addConstraint:[NSLayoutConstraint constraintWithItem:subview attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual
toItem:subviewAbove attribute:NSLayoutAttributeBottom multiplier:1.0f constant:10.0f]];
}
subviewAbove = subview;
}
}
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